There are situations when a hard drive fails (due to voltage problems, physical wear and tear, and so on) and it turns out that the information accumulated over the years is irretrievably lost (you can contact data recovery specialists, but as a rule it costs a lot of money and even not the fact that the information can be recovered) and therefore, in order to rid myself of such fears, I decided to set up a RAID1 mirrored redundancy system, which I will talk about in this video tutorial.
In general, I will devote 2 lessons to this topic, in this we will consider setting up RAID1 through the BIOS, and in the next setting up RAID1 programmatically Windows tools 7.
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 varieties of RAIDs, these are RAID 0,1,5,10, but in this video we will analyze the most common RAID1 or mirror RAID.
What is the essence of RAID1, let's say you have 2 identical hard drives, they are combined into RAID1, and the operating system sees these two disks as one physical disk, and when you write any information to this disk, it is duplicated on both disks, it turns out, as it were, a mirror image of information on both disks.
And if one of them fails, all information is stored on the second disk, and by replacing the failed disk with a similar one, the mirror redundancy system is restored.
I would like to say right away that setting through the BIOS is more reliable, but also more complicated and, perhaps, suitable for setting up on backup servers, at home it will be enough to configure the mirrors programmatically.
Well, now let's move on to the direct configuration of RAID1 through the BIOS, since it will not be possible to record this video from the screen, the setup is not done through Windows, then some screen screenshots will be in poor quality, but the point here is not in quality but in the usefulness of this information.
First, we go into the BIOS, for me it looks like this. IN various models Motherboard settings may differ, but the principle is the same. We need to find the configuration menu for SATA or IDE devices, I have this menu located in Advanced \ SATA Configuration \ Here in the menu SATA mode, select RAID, save changes and exit the BIOS.
The computer is rebooting 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. RAID is not
The serial number of the device, I have 2 of them
Model hard drive(it is advisable to use disks of the same manufacturer and brand so that they are absolutely identical)
The volume of each disk (the volume must be the same on both disks, otherwise creating a mirrored RAID will not work)
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
Resetting all drives to a non-RAID state (if there are multiple RAIDs, all RAIDs will be deleted)
I did not use the following two points at this stage, so I can’t 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 with us.
Now, in the information about RAID arrays, there is a RAID named Mirror, Type RAID1, with a capacity of 931.5 GB, the status is normal and it can be bootable.
If you want it to have an operating system, 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. crashed while loading blue screen, therefore, 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, we go to the device manager \ Disk drives and see the Mirror storage device there, i.e. this is the RAID1 mirror disk.
After disconnecting one of the disks, the following message appears at boot with the RAID status Degraded (Degraded, i.e. one of the disks is missing in the RAID), but regardless of this, the operating system continues to load.
Now I booted from a failed RAID, this can be seen using a special program that comes with the drivers for motherboard.
Now I reconnect the disk and the RAID state goes to Rebuild (reconstruction, in this state data from the mirror is copied to the connected disk in order to restore the RAID to work, depending on the size of the disk, this process can take a long time)
We load the OS and again look through the program to see what happens with the RAID, everything is OK, the raid is restored, and reconstruction is performed with the installed disk. After finishing this process, everything will work as before.
Again, before experimenting with RAID, it is better 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’s no way to protect yourself, except perhaps to store a copy of documents on a dedicated server) But, again, if the system is implemented on a backup server, then if everything burns down, then in any case, copies of documents should remain at the workstations, well, unless all the computers in office J have burned down
Hardware RAID (software RAID is created by software, no software is bug-proof, so RAID via BIOS is more reliable)
I have 2 disks of the same size, on one there is a win7 system, now it is done as in the screenshot, but it confuses me, the moment that the 100mb area is not mirrored.
How to mirror the system partition so that if you physically pull out 1 disk (when it fails), win7 can boot just as quietly?
Something terrible happened, after I normally completed the work (but apparently the disks did not finish resynchronization), the computer did not want to boot and hangs on "Verifying DMI pool data” .
I tried to turn off alternately 1 disk, in one case it also writes.
I tried explicitly through F12 to select boot disk.
I tried to restore Windows from a flash drive (with a cat. I installed win7). 
And nothing helped despite the fact that it is written that the partition table was restored.
Here is what shows from the boot disk when viewed through command line using diskpart 
Moreover, from other separate physical test disks, ubuntu and win7 boots normally.
Hello friends! If you look at the comments of readers on our website in the section on repairing hard drives, you will be amazed at how many people were not ready for the fact that their storage device suddenly failed and all important files: projects, plans, diplomas, drawings, calculations, over which a person worked for several months in a row, simply disappeared into nowhere. difficult even for a professional repairman, not like a simple user. Therefore, eIf you care about personal data, be sure to read today's article. In it, we'll show you how to createRAID-1 array of two HDDsin latest Windows 10 Fall Creators Update. It is very easy to do this, because the technology« disk mirroring» built into the operating system.
This article differs from because "Mirror» we will create directly for system disk(C:) and right in running Windows 10!
At the beginning of the article, I will remind you that a RAID array or "Disk Mirroring" is a parallel recording of data on two hard drives. When one breaks HDD all information remains safe and sound on another hard drive. That's the whole secret!For a better assimilation of information, we will consider everything on a specific practical example, so you will understand everything much better than I would now begin to tell you the theory.
Creating a RAID Array or Mirroring Drives in the Latest Windows 10 Fall Creators Update
Let's take an ordinary computer in the organization where I work.
Right click on the start menu and select "Disk Management".
In this window, you can notice two hard drives connected to the PC.
The first disk (Disk 0) contains two partitions: (C:) and (D:) . On disk (C:) Windows 10 installed. The OS desktop contains important working folders. If the folders disappear for any reason, then the work of the entire organization will stop for several days, and I am even afraid to imagine all the consequences. On disk(D:) there is no serious information, only movies and photos. Therefore, I will create a mirror for one system partition(C:).
Second HDD(Disk 1) is absolutely clean and contains no partitions, its entire area is unallocated. It is on it that we will create a disk mirror (C:). All information recorded on the system disk will also be duplicated on the mirror disk.
It is important that the HDD from which we want to create a mirror is unpartitioned and no smaller than the original disk on which the operating system is installed. In our case, both hard drives are exactly the same.
Right-click on the drive (C:) and select "Add Mirror..."
Windows 10 will prompt you to select the drive that we want to use as a mirror. Select the empty Disk 1 with the left mouse button and click« Add mirror volume ».
There is a warning about that now the disks will be converted to dynamic and if you have several operating systems, then after the conversion you will be able to boot only the current operating system. Will explain.
Tune RAID-1 array or Disk Mirroring is only better if you have one operating system installed on your computer that has one bootloader. If you have several operating systems installed on your PC, for example, Windows 8.1 and Windows 10, then you can mirror disks in the Windows that was installed last. That is, you setWindows 8.1, then Windows 10, in this case customizable RAID-1 array in Windows 10 and after that, only Windows 10 will boot on the computer. If you configure RAID-1 array in Windows 8.1, then no Windows will be loaded on the PC at all. This problem is connected with the peculiarity of the work of dynamic disks, about which it would be nice to write a separate article, but all hands do not reach.
There is only one OS installed on my computer. I press "Yes".
The disk resynchronization process begins when the mirror is created. In simple words, Windows 10 creates an exact copy of the drive (C:) on the second hard drive (Disk 1).From the unallocated space, you can create a partition and use it without any problems.
The resynchronization process is complete and the OS is ready to go.
Setting up a software RAID array in Windows environment a much simpler task than under Linux systems, however, it also has its own characteristics. Often, incomplete and fragmentary knowledge in this area leads to difficulties, and among administrators there are myths and legends about the "capriciousness" and "buggy" of this mechanism in Windows. In this article, we will try to fill this gap.
Before continuing, let's recall the basic principle of building hardware arrays again: one element of the array is one physical disk. The basis of software arrays is a logical disk. Understanding this difference is the key to success, what is applicable to a hardware array can be disastrous for a software one, especially when it comes to the failure of one of the array elements.
To create a software RAID in a Windows environment, we need to get acquainted with the concept of a dynamic disk, since software arrays can only be created on them. The reputation of dynamic disks is mixed, many administrators shy away from them like hell from incense. And in vain, remembering a few simple rules working with dynamic disks becomes as easy as with conventional ones.
The main rule: installing or booting Windows from a dynamic volume is only possible if this disk has been converted from a system or boot volume. Those. if you have several instances of the OS, then after converting the disk to dynamic, you can only boot the instance that is on the boot partition.
Based on this rule, it becomes obvious that only a mirror array (RAID1) can be created for the boot and system volumes, the creation of other types of array is impossible, since they imply installing the system on a pre-created partition.
Is the game worth the candle? Despite all the limitations, it's worth it. The main disadvantage of hardware arrays is the binding to a specific controller model. If your motherboard or controller burned out, you will need exactly the same one (or a motherboard with a similar controller), otherwise you can say goodbye to the data. In the case of software RAID, a machine with installed Windows server.
In practice, work with software arrays and dynamic disks is performed through the snap-in Storage - Disk Management in Server Manager. To convert disks to dynamic, just right-click on one of them and select Convert to dynamic disk, in the window that opens, you can select several discs to convert at once.
It is worth remembering that this operation is irreversible and special attention should be paid system partition, you will no longer be able to repartition the boot disk (more precisely, after that it will cease to be bootable), the only thing you can do is expand the volume using unallocated space.
The next step is to create an array, right-click on the desired volume and select the desired option, in the case of system and boot volumes, there will be one option - a mirror, then you will be prompted to select a disk to host the mirror volume. Upon completion of the creation of the array, its resynchronization will immediately begin.
By connecting additional disks, we will get much more opportunities, you can either combine several disks into a separate volume, or create RAID 0, 1 or 5.
In general, nothing complicated, but many restrictions can scare anyone away. But do not rush to make hasty conclusions, there are no serious obstacles on common sense, since it is usually customary to spread the system and data over different disks, given the penny cost of modern disks, this does not entail significant costs. For example, we created a mirror for the system disk and RAID5 for data for our test server.
Moreover, all this pleasure can be realized on the most ordinary budget motherboard, given that the performance of a software array is no different from cheap hardware, this technology looks very attractive. We will talk about methods for ensuring fault tolerance and actions in case of disk failure in our next article.
Disk Mirroring in Windows 8 and Windows 7
Hard drives are the main storage of information on a computer. But, unfortunately, they do not last forever. And it's very annoying to realize one day that "accumulated by overwork" suddenly disappears due to disk failure. In some cases, data can be recovered. But usually only partially. And that is 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 transfer 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 for Reserve copy data, in addition, the data from the last copy to the crash of the disk will still be lost.
In order not to bother with external media, you can install another HDD in your computer and periodically copy data to it. It would be 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 hard drives combined in a special way. There are several types of RAIDs, the most popular of them are "RAID-0" - 2 disks connected in series for faster data read-write, and "RAID-1" - 2 disks connected in parallel for simultaneous data writing to both HDDs. If one of the drives fails, the other drive is left with a mirrored copy of the data, and the chances of two drives failing at the same time are very low. RAID-1 is commonly called a "mirror", and the parallel inclusion of several 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 RAID controllers built into the motherboard is quite deplorable. As a rule, manufacturers, in order to reduce the price of the 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 RAIDs" have recently become increasingly popular. parallel writing of data to 2 disks is performed not at the hardware level, but at the software level. A special program keeps track of all data writing operations on a particular disk and writes the same data to another disk.
In Windows 7 and Windows 8 operating systems, developers have built software RAID into the OS 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 mirrored will remain working. And if you perform the actions incorrectly, then not a single working OS will remain. 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, nothing threatens your Windows.
So, in order to see all the pitfalls of data mirroring using OS tools, I use a computer with 2 installed operating systems - Windows 7 and Windows 8. 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? It is necessary that the computer has 2 physical hard drives. It cannot be otherwise - copying the disk data to it itself is meaningless, since when the disk leaves the erase, we will lose both the data and their copy at the same time. The advantage of software RAID is that, unlike hardware RAID, it can be configured for individual logical drives, and not just for the entire physical drive as a whole.
To create a mirror, you must enter Disk Management. To do this, go to the Control Panel and select "Administration".
Section Administration in the Control Panel
In Administrative Tools, find "Computer Management".
Administration tools
In the Computer Management window on the left, select "Disk Management".
Disk Management
The figure shows 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 drive must have unallocated free space equal to or greater than the size of the mirrored drive. 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" from the context menu.
Adding a mirror
The system will prompt you to select a drive that will be used as a mirror.
Selecting a disk to create a mirror
Select the desired disk from the list and click "Add Mirrored Volume". Here's an interesting warning:
OS warning about the inability to start other versions of Windows
We are warned that the disks will be converted to dynamic and if several operating systems are installed on the computer, then after performing this operation, only the currently running OS will remain working. We will check this later. We press "Yes".
The process of creating a mirror will begin - if there is any data on disk F, they will be copied to the mirror disk.
Synchronizing disks when creating a mirror
After the completion of all processes, we get this picture.
The result of creating a disk mirror
As you can see, the system has taken space from the second disk, the volume of which is equal to the volume of the mirrored disk. The rest of the space of the second disk is left unallocated and can be used as you wish, 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 steps under Windows 8. Let's try to load Windows 7.
We restart the computer, we get a list of OS selection.
Boot OS selection
We select Windows 7, the boot process begins and ... we get this.
Mistake Windows boot 7
Now about the pitfalls that I mentioned at the beginning of the article. I knowingly made a reservation there that Windows 8 was installed after Windows 7. What does this affect? The fact is that a computer can only have one OS loader. 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 bootloader so 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 it starts Windows bootloader 8, which was installed last, and offers a list of found operating systems. Now let's imagine that I would configure mirroring not on Windows 8, but on Windows 7. In this case, Windows 8 would become inoperable. And along with it, its bootloader would also cease to function, and I would lose the opportunity to run any OS on my computer at all - verified by experience. The solution to this problem can only be reinstalling Windows.
In this way, if you have several operating systems installed on your computer, you can configure mirroring only in the last installed OS, while all other operating systems will automatically become inoperative and it will be impossible to bring them back to life- we'll see later .
Once again, if you have only one operating system, everything we are talking about will not cause either it or the computer as a whole the slightest harm.
So, the mirror is configured, now all data written to the disk will be automatically written to another disk. How to 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 - a mirror. To make this clear, let's "disassemble" the mirror.
Go to disk management again, right-click on any of the 2 mirror disks and select "Split mirrored volume".
Partitioning 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 will get two separate logical drives. The system immediately assigned the letter G to the new disk (the former mirror).
Mirror Split Result
Now in the explorer, in addition to disk F, we will also see the created disk G.
Computer disks after splitting a mirror
And on both previously mirrored disks, we will see the folder we created, and inside it is a file.
Result of data mirroring
We made sure that the mirror works and if necessary we can "disassemble" it without any data loss.
Will we be able to boot a second OS after splitting the mirror? We try and as a result we get this again.
Error booting the second OS of the computer
Thus, by configuring mirroring, you will forever lose the ability to run other installed Windows operating systems on your computer.
The downside of disk mirroring is the loss in space - we use two disks as one. But information costs more than discs. If you still 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 remove one of the disks from the mirror - then we will get one disk with data and a second disk with unallocated area.
To remove a disk from a mirror, just right-click on one of the mirror disks in the disk management window and select "Delete Mirror".
Removing a disk from a mirror
Selecting a disk to remove from the mirror
Click "Remove mirror" and get this picture.
Disks after mirror removal
The disk from which the mirror was removed returned to its original state - it is now not dynamic, but again basic, but Disk 0 remained dynamic, which means we still won’t launch the second OS from it.
And one more subtlety is that if we remove the mirror from Disk 0, it will not become basic, but remain dynamic.
The system disk remained dynamic after removing the mirror
Thus, by creating a mirror, we deprive ourselves of any chance to use the second OS on the computer.
But not so often at home you have to install several operating systems on one computer, but almost everyone needs data backup. Therefore, this feature is very useful and I advise you to use it. All that is needed for this is installed on Windows computer 7 or Windows 8, as well as the presence of an additional hard drive of the required volume.
