How to make a disk mirror. Windows Server

Services

Read about the Windows Disk Space feature. Namely, how to create a software Raid from several physical disks on your home PC yourself, including built-in or connected via USB using this function, and restore data from it.

The Disk Spaces function built into Windows 10 allows the user to create one virtual hard disk from several hard disks. With its help, you can back up data by duplicating it on multiple disks or combine several hard or SSD disks into a single storage pool. Disk Spaces is the same as RAID, only on a desktop computer and with hard drives attached to it.

Content:

Windows "Disk Space" feature

This feature first appeared in Windows 8 and has been enhanced in Windows 10. Storage Spaces are available in all versions of Windows 8 and 10, including Home.

To create Disk Space, at least two physical disks must be connected to the computer, including built-in or USB-connected.

Using the Storage Spaces function, you can create a storage pool of two or more physical disks by grouping them together. After creating a storage pool from two or more physical disks, you can create three resiliency spaces:

Simple type... Designed to create a disc of the largest possible volume. This type of space does not protect data in any way in the event of a possible failure or failure of one of the disks. On such a disk, Windows will save all data in one copy. In the event of failure of one of the physical disks, all data stored on it will be lost. This type of disk is convenient when you need to temporarily store large amounts of data.
Mirror space is designed to protect data in case of a possible failure of a physical disk, by saving multiple copies of files. In case of failure of one of the physical disks of space, the data stored on it will remain available from the other disk on which their copy was created. This type is useful for protecting sensitive data in the event of possible hardware failures.
Even space Is a cross between a simple and a mirror type. Data is striped across multiple physical disks, creating one or two copies of the parity information. However, due to the need to calculate checksums, the parity space is noticeably slower for writing, as a result of which they are recommended for storing data archives. For example, a photo or video.

How to create disk space

Create a Disk space using the corresponding menu in.

But before you start creating it, connect to the computer all hard drives from which you intend to create Disk space... Then select from the menu / Create new pool and disk space.

Select the disks to add to the pool and click "Create pool".

Please note that all disk data from which the disk space is created will be deleted.

After creating a pool, you need to set up a new disk space: assign a name to it and select a drive letter. It is with this name and letter that it will be displayed in Windows.

Also, you can choose the standard Windows file system - NTFS, or the new type of system ReFS. In the case of creating a mirrored or parity space, which are designed to protect data from loss, it is better to choose the type of ReFS system.

Indicate the type of resistance: Simple (no stability), Two way mirror, Three way mirror, Parity.

To create a large storage pool without disk failure protection, select the type Plain (no stability). A two-way mirror involves storing two copies of the data on disk, and Trilateral - three. Disk space with type Parity will protect in case of failure of one of the disks, and will be larger than a two- or three-way mirror, but will be much slower.

Depending on the selected resilience type, the wizard will set the maximum currently available disk space. However, you can also set a larger data pool size. This is intended for the case when the available space of the connected physical disks becomes full. So that the user can connect another disk without having to make changes to the disk space configuration.

Then press "Create Disk Space".

How to use Disk Spaces

The created disk space will appear as another disk in the folder "This Computer"... Such a disk will have the name and letter that you assigned to it during creation and will not visually differ from other disks.

You can do everything with this disc as with another regular disc. Even encrypt it with Bitlocker.

How to manage disk spaces

After creating disk space, you can go to Control Panel to manage or customize it.

Another disk space can be created. Their number is limited only by the number of physical disks connected to the computer. You can add disks or rename the storage pool.

You can change the name or letter of the disk space by clicking the menu "Change" in subsection.

To add disks to an existing disk space, select Add Disks and select the disks to add. By choosing the Optimize Disk Usage menu, Windows will redistribute existing data evenly across all disks.

If the existing disk space consists of three or more physical disks, then one of them can be removed. To do this, expand the physical disks menu and select the link "Prepare for removal"next to the drive you want to remove. In our case, there is no such link, since the disk space consists of two disks.

After that, the system will transfer the data from the removed disk to two (or more) other physical disks of the disk space. As a result, the link "Prepare for removal" will change to "Delete".

The physical disk removed from the disk space will become available in Disk manager... To be able to work further, you may need to create a new section on it and format it.

In the management of disk spaces, the user also has access to the function of deleting the disk space itself (to the right of the disk space name, subsection). Just keep in mind that all data in the deleted disk space will be deleted.

In case of deleting disk space, the menu will become available "Delete pool", by selecting which you can completely remove the storage pool.

How to recover data from a disk space or mirrored volume

What to do in case of data loss from disk space? Is it possible to recover them?

In case of failure of one or several disks of the disk space, the process of data recovery from it becomes very complicated and cannot be reduced to scanning each disk separately with a data recovery program. In this case, the data will not be restored or will be restored damaged.

The only exception is mirrored disk space, which is created as RAID-1. Since in a disk space of this type, a copy of the data is created on each of the disks.

To do this, it is enough to scan the logical disk in the form of which the disk space is displayed using Hetman Partition Recovery. Then find and recover lost files or folders in the same way as from any other disk.

How to create a mirrored, striped, or spanned volume in Windows 7 or older

As mentioned at the beginning of this article, the Disk Spaces feature has appeared in Windows since version 8. But before that, the system also provided the ability to create disk spaces. You can create a mirrored, striped, or spanned volume in Windows 7 or older using the Disk Management menu.

Because Disk management is present in Windows 8/10, so you can create disk space in the latest versions of the system in the same way.

To create disk space using Disk Management, you need two or more disks connected to the computer, which will not be allocated. If a partition will be created on the disk from which you plan to create a mirrored volume, delete it. To do this, right-click on it and select "Delete volume ..."... Note that this will erase all data from the disk.

After that, again right-click on the disk from which the disk space is supposed to be created, and, depending on the task, select the type of volume to be created. They are somewhat similar to the types of disk space resiliency described in the first part of this article.

So, Simple volume Is a part of a physical disk that functions as a separate physical block. It is nothing more than a normal logical partition on a physical disk. It is not disk space, as we are talking about in this article.

Composite volume connects areas of free space of two or more physical hard drives into one logical drive. It consists of at least two unallocated parts on two hard drives, which are combined into one common when created. If you create a spanned volume that includes 150 GB from one hard drive and 250 GB from another hard drive, then a 400 GB local drive appears in the This PC folder. The performance of a spanned volume is higher than that of a simple volume, and the fault tolerance is the same. Creating a spanned volume is suitable for solving the issue of local disk space.

Striped volume is a non-redundant array configuration. Information is split into blocks of data and written to multiple disks at the same time. Failure of any disk destroys the entire array. Since the array is not redundant, there is no recovery procedure in the event of a single physical disk failure. Reliability depends on the reliability of each drive. The array is not intended to provide reliable storage of data, but to improve performance.

Mirrored volume Is the same as the mirror space. It is designed to protect data in case of a possible failure of a physical disk, by saving multiple copies of files. In case of failure of one of the physical disks of space, the data stored on it will remain available from the other disk on which their copy was created. This type is useful for protecting sensitive data in the event of possible hardware failures.

Volume RAID-5, as well as even space, a cross between a simple and a mirror type. Data is striped across multiple physical disks, creating one or two copies of the parity information. However, due to the need to calculate checksums, the parity space is noticeably slower for writing, as a result of which they are recommended for storing data archives. For example, a photo or video. To create it, you need three or more disks.

I choose " Create mirrored volume ... " and in the resulting Image Wizard, click "Further".

Select the disk that you want to add before the mirrored volume (other than the one that was originally right-clicked) and click Add / "Further".

Assign a drive letter.

Give the volume a name and format it.

Before formatting begins, the system will warn you that it will convert the basic disks selected to create the mirrored volume to dynamic disks.

This will start formatting and converting the disks to a mirrored volume. In the Disk Management window, the disks of the mirrored volume will appear in brown, and in the This computer folder, as one of the local disks.

In this article, I will give an overview of the possibilities for organizing RAID arrays using the built-in tools of Windows Server and in detail about the pitfalls that can be encountered when creating and operating such arrays.

Features of Software RAID in Windows Server

The following arrays are supported:

striped volume (RAID0)
mirrored volume (RAID1)
rAID5 volume
spanned volume (one logical volume is located on more than one physical disk)

Dynamic disks

RAID arrays can only be created on dynamic disks - a special layout of physical disks (understandable only by Windows), which has the following features:

A regular (basic) disk can only be converted to dynamic as a whole.
Converting a dynamic disk back to basic is possible, but only if you delete all volumes from a dynamic disk.
A dynamic disk is a single large NTFS partition, on which a large number of volumes (both simple and RAID) can be located using clever service information, it is possible to resize simple volumes using standard Windows tools. However, I don't know how optimally and fragmented the data will be.
The cloning, repairing and resizing programs I know of do not support dynamic disks.
Dynamic disks containing RAID volumes can be migrated to another Windows Server computer as they contain the information required to properly assemble the array.

Unable to create volumes with different RAID levels

Only one type (level) of RAID volumes can be created on one Physical Disk Group. For example, if we have 3 physical disks and we created a RAID5 volume on them without taking up all the space. We will not be able to create volumes of other RAID levels (RAID0 and RAID1) in free space, but only RAID5 and simple volumes.

Simultaneous volume synchronization

If several RAID volumes have been created on the same Disk Group, then in the event of any failure after the computer boots, they begin to recover simultaneously. This is a fierce, furious EPIC FAIL! A simple situation: there are two physical disks, two RAID1 volumes are created on them, one for the operating system, the other for data.

This scheme works great until the first failure (the simplest types are a sudden power outage or blue screen). And then the horror comes. The operating system boots and at the same time starts synchronizing both RAID1 volumes at the same time. Thus, physical disks receive competing instructions for intensive sequential operations in three different physical areas at once. At the same time, the mechanics of the disks wear out wildly, the cache is useless.

From the outside, such "fault tolerance" looks like this: the overall performance of the disk subsystem drops every 20, the OS itself will boot either after the synchronization of one of the volumes (15 minutes, if it is small, gig by 50), or after 20 minutes and will be useless until end of synchronization of one of the volumes.

I consider the above behavior to be an unacceptable architectural miscalculation on the part of Microsoft and am surprised that this problem has not been resolved until now since the introduction of software RAID in Windows 2000 Server.

If you find yourself in the described situation, then you should not wait for the OS to load and wear out the disks.

Disconnect one of the physical disks.
Boot into the OS at normal speed.
Break the mirror by making the RAID1 volumes simple.
Connect the second drive back.
Create only one mirror for the volume you need.

RAID5

I will describe a scenario in which you cannot restore a degraded RAID5 array to a healthy state, even if all the conditions are provided for this.

There is a six-disk RAID5 array (Disk1-Disk6).
Among them there is one faulty Disk1 (for example, a couple of megabytes cannot be read from a terabyte volume), but the operating system does not yet know about it and has not marked it as faulty.
For some reason, a healthy Disk2 was disconnected from the array.
Following the logic of RAID5, if one disk fails, the performance of the array remains, such an array is marked as degraded, its performance drops sharply, synchronization with a new serviceable disk is required.
A working Disk2 is connected in place. The system recognizes him as faulty. To sync the array, this failed drive must be removed from the RAID5 array and defined as empty.
Everything is ready to synchronize the array. Run the repair of the array (repair) on an empty Disk2.
SUDDENLY synchronization stumbles upon read errors on the really bad Disk1 and stops.
The whole massif remains degraded. Disk1 is marked as containing errors, Disk2 is marked as online, however due to interrupted synchronization it does not contain complete correct data.
In the hope of recovery, a completely new working Disk7 is connected. The restoration of the array to it is started.
As a result, the healthy Disk2 is replaced with another healthy Disk7, but the synchronization is interrupted again after finding an error on the defective Disk1.
And so on in a cycle.

You cannot do anything except copy the still-readable data and rebuild the entire array.

Not wanting to admit defeat, I tried to do the following things:

Synchronize the array with skipping read errors on Disk1 (after all, these are just megabytes of a whole terabyte). But Microsoft doesn't offer that option.
Overwrite the entire faulty Disk1 sector-by-sector to another healthy disk using cloning programs. However, the programs available to me did not work with dynamic disks.

An example of a competent implementation of software RAID

The hardware and software implementation of the RAID controller, known as Intel Matrix Storage, and recently renamed Intel Rapid Storage (works on RAID versions of chipsets such as ICH9R, ICH10R), has been spared the above drawbacks. Intel hardware-software RAID provides many of the benefits of an "adult" RAID controller:

ability to identify hot swap drives
the ability to create volumes of different RAID levels on one disk group
sequential synchronization and verification of RAID volumes on a disk group

Its main drawback, in contrast to fully hardware RAID controllers, is its "software" nature, from which follows:

lack of built-in cache and the possibility of autonomous operation in case of an accident
totally dependent on operating system and drivers
the operations performed on the disk subsystem load the main processor and memory
no support for advanced computationally intensive RAID levels such as RAID6

useful links

What Are Dynamic Disks - Windows IT Pro [fairly old article]
The whole truth about dynamic disks - Hacker [read carefully, "the whole" truth is mixed with fables]

There are situations when a hard drive fails (due to voltage problems, physical wear and tear, and so on) and it turns out that over the years the accumulated information is irretrievably lost (you can contact data recovery specialists, but as a rule it costs a lot of money and not the fact that the information can be restored) and therefore, in order to save myself from such fears, I decided to set up a RAID1 mirror backup system, which I will tell you about in this video tutorial.

In general, I will devote 2 lessons to this topic, in this we will consider setting up RAID1 via BIOS, and in the next setting RAID1 using Windows 7 software.

And so, what is RAID in general, the abbreviation itself stands for an independent array of inexpensive disks and in general there are quite a few types of RAIDs, these are RAID 0,1,5,10, but in this video we will analyze the most common RAID1 or mirrored RAID.

What is the essence of RAID1, let's say you have 2 identical hard disks, they are combined into RAID1, and the operating system sees these two disks as one physical, and when you write any information to this disk, it is duplicated on both disks, it turns out as would be mirroring information on both drives.

And in case of failure of one of them, all information is saved on the second disk and by replacing the failed disk with a similar one, the mirror backup system is restored.

I would like to say right away that setting through the BIOS is more reliable, but also more complicated and is, perhaps, suitable for setting up on backup servers, at home it will be enough to set up mirrors programmatically.

Well, now let's move on to the direct configuration of RAID1 through the BIOS, since it will not work to record this video from the screen, the setting does not go through Windows, then some screenshots will be of poor quality, but the point is not in the quality but in the usefulness of this information.

First, we go into the BIOS, for me it looks like this. The setting may be different on different motherboard models, but the principle is the same. We need to find the configuration menu for SATA or IDE devices, I have this menu in the additional \\ SATA Configuration \\ Here in the SATA mode menu, select RAID, save the changes and exit the BIOS.

The computer restarts and at startup, before trying to boot the operating system, a message appears, I have this Press Ctrl + I to enter the RAID configuration utility, run the utility.

This window displays the following information

The presence of a RAID - since I have not created it yet, therefore the inscription is not defined here, i.e. No RAID

The serial number of the device, I have 2 of them

Hard disk model (it is advisable to use disks of the same manufacturer and the same brand so that they are absolutely identical)

The volume of each disk (the volume must be the same on both disks, otherwise it will not work to create a mirrored RAID)

And the status, since the RAID has not yet been created, the status is not in the RAID array

In addition to the status table, there is also a menu that consists of the following items:

Creating a RAID array

Removing a RAID array

Reset all disks to a non-RAID state (if there are several RAIDs, then all RAIDs will be deleted)

At this stage I did not use the following other points, so I cannot say anything about them.

We enter the name of the RAID, I will call it Mirror, which means mirror, then in the device manager it is under this name that this disk drive will be displayed.

Now in the information about RAID arrays there is a RAID named Mirror, RAID1 type, with a volume of 931.5 GB, the status is normal and it can be bootable.

If you want to have an operating system on it, then install the OS on it. Moreover, when I experimented, my operating system was on another disk, and after creating a mirrored RAID array, the operating system stopped loading. Those. at boot, a blue screen dropped out, so if you have an OS on another disk, you should first create a RAID, and then install the OS so that all drivers are installed correctly!

After starting the OS, go to the Device Manager \\ Disk Drives and see the Mirror storage device there, i.e. this is the mirrored RAID1 disk.

After disconnecting one of the disks, the following message appears at startup with the RAID status Degraded (ie, one of the disks is missing in the RAID), but regardless of this, the operating system continues to boot.

Now I booted from a faulty RAID, this can be seen using a special program that comes with the drivers on the motherboard.

Now I reconnect the disk and the state of the RAID goes into Rebuild (reconstruction, in this state, data from the mirrored disk is copied to the connected disk in order to restore the RAID functionality, depending on the size of the disk, this process can take a long time)

We load the OS and again look through the program what happens to the RAID, everything is OK, the RAID is restored, and the reconstruction is performed with the installed disk. After completing this process, everything will work as before.

Again, before experimenting with RAID, it's best to save important information to another medium, just in case!

As for the advantages and disadvantages of this system:

The cost of 1 GB is 2 times higher (since you will need to purchase 2 disks to store the same amount of information)

High fault tolerance (although, there are such failures in which all the hardware burns out, but there is no way to protect yourself, except perhaps to store a copy of the documents on a dedicated server) But, again, if the system is implemented on the backup server, then if everything burns out, then, in any case, copies of documents should remain on workstations, well, unless all the computers in office J have burned out

Hardware RAID (software RAID is created using a program, and no program is protected from glitches, therefore RAID via BIOS is more reliable)

Disk mirroring in Windows 8 and Windows 7

Hard drives are the main storage devices for information on a computer. But, unfortunately, they are not eternal. And it is very annoying to realize one day that the "accumulated by overwork" suddenly disappears due to the failure of the disk. In some cases, data can be recovered. But usually only partially. And that's not always the case.

How to protect yourself from data loss on hard drives? There are several solutions to this problem.

The simplest is to periodically upload important data to external media: DVD / Blu-ray discs, flash drives, external hard drives. The option is generally quite reliable, but not entirely convenient: you need to remember and find time to back up the data, in addition, data from the last copy to the disk crash will still be lost.

In order not to mess with external media, you can install another HDD in your computer and periodically copy data to it. And even better if it was done automatically.

This kind of automation has been used for a long time and it has found its expression in the so-called RAID arrays. These are arrays of hard drives combined in a special way. There are several types of RAID-s, the most popular of them are "RAID-0" - 2 disks are included in series for faster data reading and writing, and "RAID-1" - 2 disks are connected in parallel to simultaneously write data to both HDDs. If one of the disks fails, the other disk remains with a mirrored copy of the data, and the likelihood of failure of two disks at the same time is very small. RAID-1 is commonly referred to as "mirror", and parallel inclusion of multiple disks is called "mirroring".

To implement a disk array, a RAID controller must be installed in the computer. It can be built into the motherboard, or it can be installed separately.

My personal experience with motherboard RAID controllers is pretty bad. As a rule, manufacturers, to reduce the price of a product, use inexpensive controllers, the reliability of which leaves much to be desired. Some good quality controllers cost at least a hundred dollars.

In this regard, the so-called "software RAID-s" have become increasingly popular lately. parallel writing of data to 2 disks is performed not at the hardware level, but at the software level. A special program monitors all data write operations on a specific disk and writes the same data to another disk.

In the Windows 7 and Windows 8 operating systems, the developers built software RAID into the operating system itself, i.e. you can implement data mirroring using Windows tools.

I want to make a reservation right away that this functionality is not suitable for those who like to install several operating systems on one computer. In the end, only the OS that was used for mirroring will remain working. And if you do the wrong thing, then not a single working OS will be left. Later in the article I will pay attention to these points and tell you how to avoid such mistakes.

If your computer has only one operating system, you can safely use everything described below, your Windows is not in danger.

So, in order to see all the pitfalls of data mirroring by means of the OS, I use a computer with 2 installed operating systems - Windows 7 and Windows 8. At the same time, Windows 7 was installed first, and then, on another logical drive, Windows 8. We will perform the mirroring itself in Windows 8.

What is needed for this? You need to have 2 physical hard drives on your computer. It cannot be otherwise - copying the data from the disk to it itself makes no sense, since when the disk exits the erasure, we will lose both the data and their copy at the same time. The advantage of software RAID is that, in contrast to hardware RAID, it can be configured for individual logical disks, and not just for the entire physical disk as a whole.

To create a mirror, you need to go into disk management. To do this, go to the Control Panel and select "Administration".

Administration section in Control Panel

In Administration we find "Computer Management".

Administration tools

In the Computer Management window on the left, select "Disk Management".

Disk management

From the figure you can see that the computer has 2 physical disks - "Disk 0" and "Disk 1". We will create a mirror for the logical disk F (New volume) located on Disk 0. The volume of this partition is 10GB. We have a second HDD (Disk 1) with a capacity of 12GB, which we use as a mirror. The second disk must have unallocated free space that is at least as large as the mirrored disk. We have 12GB of unallocated space on Disk 1, i.e. there are no logical drives in this space.

Right-click on the desired section and select "Add mirror" in the context menu.

Adding a mirror

The system will prompt you to select a disk that will be used as a mirror.

Selecting a drive to mirror

Select the required disk from the list and click "Add mirrored volume". An interesting warning will appear here:

OS warning that other versions of Windows cannot start

We are warned that the disks will be converted to dynamic ones, and if several operating systems are installed on the computer, then after this operation is completed, only the currently running OS will remain operational. We will check this later. Click "Yes".

The process of creating a mirror will begin - if there is any data on the F drive, it will be copied to the mirrored drive.

Synchronizing disks when creating a mirror

After completing all the processes, we get the following picture.

The result of creating a disk mirror

As you can see, the system took space from the second disk, the volume of which is equal to the volume of the mirrored disk. The rest of the space on the second disk was left unallocated and you can use it as you like, for example, create another logical disk there.

Let's check if we can now boot the second OS installed on the computer. Let me remind you that in my case Windows 7 and Windows 8 are installed, we performed all the actions under Windows 8. Let's try to boot Windows 7.

We reboot the computer, we get the OS selection list.

Choosing the OS to boot

We choose Windows 7, the boot process begins and ... we get this.

Windows 7 boot error

Now about the pitfalls that I mentioned at the beginning of the article. It was not for nothing that I made a reservation that Windows 8 was installed after Windows 7. What does this affect? The fact is that there can be only one OS bootloader on a computer. And the bootloader is always the bootloader of the last installed operating system - it overwrites the previous bootloader found on the disk. But at the same time, during the installation process, Windows, having found previously installed operating systems on the computer, configures its loader in such a way that it provides the user with a list of installed operating systems at startup. From this list, we choose which OS we want to run now. In my case, the boot loader of Windows 8, which was installed last, starts and offers a list of found operating systems. Now let's imagine that I did not configure mirroring in Windows 8, but in Windows 7. In this case, Windows 8 would become inoperable. And together with it, its loader would have ceased to function and I would have lost the opportunity to run any OS on my computer at all - verified by experience. The only solution to this problem is reinstalling Windows.

Thus, if several operating systems are installed on your computer, mirroring can be configured only in the last installed OS, while all other operating systems will automatically become inoperable and it will be impossible to bring them back to life - we will see it further .

I repeat once more if you have only one operating system, everything we talk about will not cause any harm to it or to the computer as a whole.

So, the mirror is set up, now all data written to the disk will be automatically written to another disk. How can I check if it works?

Let's open the list of computer disks through Explorer.

Computer disks after mirror setup

In Explorer we see the "New volume F" disk, its mirror is not here and should not be, since everything happens at a level invisible to the user. Let's try to write some data on disk F. I'll just create a folder and a text file in it.

Folder and file on disk

If everything works correctly, the same folder and file should have been created on another disk - the mirror. To be convinced of this, let us "disassemble" the mirror.

Go to disk management again, right-click on any of the 2 mirror disks and select "Split mirrored volume".

Splitting a mirrored volume

Windows will warn us that after this action, data storage reliability will no longer be at such a high level. We agree.

Windows warning when splitting a mirrored volume

As a result, we get two separate logical drives. The system immediately assigned the letter G. to the new disk (the former mirror).

Split mirror result

Now in the explorer, in addition to the F drive, we will also see the created drive G.

Computer disks after splitting the mirror

And on both previously mirrored disks, we will see the folder we created, and inside it the.

Data mirroring result

We made sure that the mirror works and, if necessary, we can "disassemble" it without any data loss.

Can we boot the second OS after splitting the mirror? Try it and get this again as a result.

Error loading the second computer OS

Thus, by setting up mirroring, you will forever lose the ability to run other installed Windows operating systems on your computer.

The downside to disk mirroring is volume loss - we use two disks as one. But information costs more than disks. If, nevertheless, you need additional disk space, the mirror can be divided, as shown above - in this case, we will get 2 disks with the same data, or simply delete one of the disks from the mirror - then we will get one disk with data and a second disk with an unpartitioned one. area.

To remove a disk from the mirror, in the Disk Management window, right-click on one of the mirrored disks and select "Remove Mirror".

Removing a disk from the mirror

Selecting a disk to remove from the mirror

Click "Remove Mirror" and we get this picture.

Discs after removing the mirror

The disk from which the mirror was removed has returned to its original state - it is now not dynamic, but basic again, but Disk 0 has remained dynamic, which means that we will not start the second OS from it.

And one more subtlety is that if we remove the mirror from Disk 0, it will not become the base one, but will remain dynamic.

The system disk remains dynamic after removing the mirror

Thus, by creating a mirror, we deprive ourselves of any chance of using the second OS on the computer.

But not so and often at home you have to install several operating systems on one computer, but data backup is necessary for almost everyone. Therefore, this feature is very useful and I advise you to use it. All that is needed for this is Windows 7 or Windows 8 installed on the computer, as well as an additional hard drive of the required size.

18.06.2018. How to protect Windows from problems caused by hard drive damage? For this there is a backup mechanism, in particular, one with automatic creation of incremental or differential backups to maintain the current state of the OS. But there is also an alternative solution - mirroring Windows system partitions, performed by its own standard means.

This is software creation RAID in configuration RAID 1 in order to preserve information and gain access to the OS environment in case of problems caused by problems with the hard disk that ensures its existence. What are the features of this mechanism, and how to implement it in the Windows environment - we will talk about this in detail below.

1. Windows mirroring: what is it

Mirroring Is, as mentioned, software RAID 1 , a commonly used disk array configuration, in which data is duplicated onto a second hard drive called a mirror. In case of problems with the first, primary hard drive, we can use the mirror to access our valuable information. Moreover, if mirroring is applied to Windows system partitions, if the main disk fails, we will not only gain access to the information stored in the system, we will even get inside it. Not inside its original, but inside its exact clone on the disk-mirror.

Implementation of software RAID 1 possible with dynamic disk technology. This technology exists in the Windows environment, starting from the version 2000 ... The technology itself is applicable to both MBR - and to GPT -disks, but here's the creation of software RAID 1 complicated by the need to perform additional operations with the command line. So everything that will be proposed below applies only to MBR -discs. Creation of software RAID possible only in OS editions, starting with Pro.

When reinstalling the system on dynamic disks, you do not need to inject specific drivers into the distribution RAID-controller, as required by the hardware RAID... As well as there is no need to reinstall anything when using any of the configurations of the software RAID... However, in the conditions of working with dynamic disks, we cannot use more than one Windows. OS installed on other partitions will simply not boot. Technology works by rule "Entry - one ruble, exit - two": the initial basic disks with structure and data are converted into a dynamic type easily and simply by Windows tools, but the opposite direction works only for disks with an unallocated area. If the structure and data are there, you will have to resort to third-party software.

Another important nuance: to work with this technology, it is important that the computer name contains only Latin characters. Otherwise we will get an error "Invalid package name".

2. Preparatory stage

For Windows application RAID 1 a second hard disk with a capacity of at least the total volume of both system partitions must be connected to the computer.In our case, those occupy, respectively, 549 Mb and 60 GB, and the mirror disk has a volume with a small margin - 70 GB... The mirror needs to be prepared for its further fate - to delete all sections on it. A clean unallocated area should remain.

Information about booting installed on other Windows partitions, if any, is better to remove and leave the ability to start only the current system. When mirroring, the boot menu will be overwritten, and there will be a record of loading only one OS with the addition of the ability to launch its clone on a mirrored disk. So it is important that there is a record of loading the necessary Windows. Otherwise we get BSOD .

We will implement mirrored Windows using the system utility diskmgmt.msc , she's a console "Disk Management".

3. Convert disk to dynamic

On any of the two disks, call the context menu, select converting them to dynamic type.

Check both of them. Click "OK".

We press "Convert" and confirm the action.

4. Creating mirrors of system partitions

So, both disks - both the main and the mirror - are now dynamic. Call the context menu on a small technical section of the system (bootloader section) ... We choose "Add mirror".

Click on the mirror disk. We press Add Mirrored Volume.

Then we will see how a clone partition was formed on the mirror and the data synchronization process started.

Now we press the context menu on the main Windows partition, on the disk WITH ... And we do the same operation as above. Add a mirror.

Now we have configured data synchronization with the mirror. We can dispose of the unallocated area remaining on the mirror disk in any way: leave it as it is, create a separate partition from it, attach the space to some other partition (and on any of the disks, because we are now working with their dynamic type) .

5. Mirror Windows

As soon as the data is synchronized with the mirror, and we find out about the completion of this process by the degree of load on the disk in the task manager, we can reboot and test the performance of the mirror Windows. Access to it, as mentioned, will appear in the bootloader menu, it will appear with the inscription "Windows such and such version is a secondary plex" ... The bootloader menu, by the way, in the last two OS versions can be configured right at the stage of computer startup.

You can set a shorter time for Windows autoselection.

The system will boot first on the main disk, so you can choose the minimum 5 seconds to display boot options.

In older versions of Windows, the timeout for the bootloader menu is configured in the system utility "System configuration".

6. Removing Windows mirrors

If you no longer need to mirror Windows, you can delete its mirror. This is done in the same place where this mirror was added - in the utility diskmgmt.msc ... In turn, click each of the system sections, in the context menu, click Remove mirror.

Select the mirror disk, press the delete button and confirm.

The space of the mirrored disk will turn into unallocated area, and its type is converted from dynamic to original base.

7. Reinstall Windows under mirroring conditions

Reinstallation of Windows in the conditions of existence of mirrors of its partitions is carried out in the same way as usual - we can delete two of its partitions and specify an unallocated area with the OS installation location, or we can simply format its two existing partitions.

In any of these cases, when you reinstall Windows, its mirror will not go anywhere, it will continue to function in the new system. Program RAID 1 transferred to a new, reinstalled system environment. And everything would be fine if we mirrored regular user sections with our data. But the software RAID 1 for system partitions, remember, it also provides for the ability to enter Windows on a disk-mirror. And here we come across another Microsoft jamb: the record about loading the mirror system will be lost - the very same bootloader menu item with an additional note "Secondary plex" ... After all, we formatted or deleted a small bootloader partition when installing the system. Leaving it as it is, not formatting it is even more dangerous. Let's remember that only one Windows can boot on dynamic disks. If the bootloader partition is not formatted, the new system will appear second in the boot menu and will not be able to start. Likewise, neither the first system nor its mirror will start, because the first one no longer exists, and its mirror is a clone of a non-existent Windows.

So the Windows boot partition when reinstalling it must be either formatted or deleted. How, then, do you ensure that you log into mirrored Windows? The solution here is very simple: you need to recreate the mirrors of the system partitions - delete them, as discussed in the previous paragraph, and reassign. The mirror disk is re-synchronized with the system partitions, and in the Windows bootloader menu, the item of the mirror system with an additional note appears again "Secondary plex".

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