Convert non-RAID 1 to RAID 1

[jpanhalt]

My data drives are all RAID 1 , but from the earliest days, my OS and other programs (C Drive) are on a non-RAID drive, which is now an SSD.  I figured reloading everything every once in awhile was a good way to clean Windows.  I am now on Win7 Pro and will be there for as long as possible.

Can the C Drive be copied to a RAID 1 pair, and that drive then made default (i.e., C)?  More simply, is there any way to add just one new drive and convert the current C-drive to RAID1 without erasing it? 

(Why am I worried?  Unfortunately, I have had two RAID SSD's die in the past 4 years.  The first died about 2 years after installation, and the second died last week 4 years after installation.  Both drives were Samsung "EVO."  The latest was a V-NAND 850 EVO.  I am worried about getting all my good old trusty programs re-installed and activated today.)

[retiredfeline]

There is a way involving creating a degraded RAID-1 array on the second drive, copying the C contents to that, and then adding the C drive as the missing RAID partner. I did this years ago following this article, but it's for Linux, not Windows.

https://feeding.cloud.geek.nz/posts/setting-up-raid-on-existing/

Good luck.

[Microdoser]

In windows, once you have fitted the empty drive,

go into the partition manager (start menu, search for 'part', select 'create and format hard drive partitions')

make your boot drive dynamic (right click main drive on the grey box at the bottom left where it says 'Disk 0' or whichever is your C drive mine is Disk 1, choose 'convert to dynamic disk')

select the empty drive as a mirror of your main drive (right click main drive, choose 'Select Mirror'or 'Add mirror', select empty drive), it may be that the empty drive has to be converted to a dynamic disk also but from memory I do not think this is the case. Try it if you have problems selecting it as the mirror.

Then windows will then happily chug away, making the drives into RAID 1.

I'm not on Windows 7 any more, so some of these steps may have slightly different text for the options.

[jpanhalt]

Then windows will then happily chug away, making the drives into RAID 1.

Interesting.

Does that mean it will be independent of the Intel RAID controller currently being used?

[Microdoser]

Yes, it will be a software RAID via windows

[Nominal Animal]

Because there is basically no computation involved in RAID-1 (nor RAID-0) –– unlike say RAID 5 or RAID 6 which involve calculating a checksum for each block –, there is no benefit in using a dedicated RAID controller for RAID-0 or RAID-1.  JBOD, or Just a Bunch of Disks, with software-RAID, works just as well if not better.

In Linux, the software implementation is so efficient at these RAID levels that in testing (over a decade ago, granted) it beat all hardware-RAID adapters.  It was glorious when just a few spinning disks in parallel could get you gigabyte per second sustained transfer rates...

Now, RAID-5 or RAID-6 is a completely different thing, due to that checksum calculation: there, it is more efficient to use dedicated hardware for that, so that from the processors' perspective, the storage appears as just a single device, and the controller handles the RAID stuff, hotswap, etc.

[David Hess]

Can the C Drive be copied to a RAID 1 pair, and that drive then made default (i.e., C)?

Yes, and I have done that many times using programs like Partition Magic or Acronis Disk Director.

More simply, is there any way to add just one new drive and convert the current C-drive to RAID1 without erasing it?

That is sometimes possible with specific RAID implementations, but I would not count on it.

In either case, the RAID must be visible to the BIOS and Windows to support booting.  I now have two systems which run Windows 10 and boot from Areca RAID controllers.  On one of them I have copied the boot volume to a single drive and back to the RAID several times as I changed the hardware.

In the past I have also booted from motherboard RAID implementations however with some rare exceptions, I have found reliability of common motherboard RAID implementations to be poor.

[magic]

The BIOS needs not to know anything if either:
a. the boot chain includes a bootloader which understands the software RAID employed
b. software RAID keeps its metadata at the end of each partition and the beginning of the partition looks like a normal filesystem

Option b is somewhat dangerous in that RAID-unaware software may potentially not only read but also modify one of the mirrors and thus desynchronize the array.

[gnif]

Just a note for those using their motherboard RAID features... unless you actually have a server/workstation motherboard with a true integrated RAID controller, you don't have hardware RAID. The RAID in your BIOS is simply an enhancement that allows your system to start booting from a software raid set, the OS still has to manage it in software and it might even be in a proprietary format in some cases (ie: AMD RaidXpert II on NVMe) making recovery from a fault/failure far harder.

If you truly value your data and can't afford to lose it I have two suggestions.

1) Get a real RAID controller and run RAID5 of better (note, there are still issues with RAID even with a HW controller that can cause data loss, see "RAID write hole")

2) Setup a cheap TrueNAS server:
  * Get a cheap used/obsolete server with (or add one to it) a SAS RAID controller that can run in IT mode (ie, JBOD).
  * Install some ECC RAM, (DDR3 ECC ram is very cheap to buy used in large quantities)
  * Install your SAS disks (again, can obtain used SAS drives pretty cheap because enterprise users don't want used drives, and home users can't generally use SAS disks).
  * Install TrueNAS and configure a ZFS RaidZ2 or better array.

Option 2 is more involved, but gives you higher performance, better data security, infinite zero cost snapshots, and is immune to the RAID write hole issue.
If you want to go one step further you can then setup iSCSI and use it as your desktop's HDD instead of even bothering with local storage (suggest a gigabit network or faster though).

Also, RAID is not BACKUP, a bug/virus that deletes your files deletes them from all your cloned disks. This is where ZFS shines as snapshots act like a backup (note you should still have a regular off-site backup schedule in case of system failure, fire, etc).

I setup Option 2 at home about a year ago now (prices all AUD):

* Used 1RU xeon server - $200
* 64GB of ECC RAM - $160
* LSI SAS card - $40

$400 without disks

This is not strictly required, I just have large storage requirements, most 1RU servers have provision for 4 disks, sometimes more internally.
  * 12x 5+1⁄4" SAS disk array for $400

I am using SAS 4TiB HDDs, $80 each, new old stock (which is in large supply). You can get cheaper if you want used stock, usually around $60 each.
I also added an intel Optane 800p NVMe SSD to the system as a L2 cache which accelerates reads & writes enormously, this model is available very cheap as the industry has moved away from them (I paid $30).
With 8x SAS drives I can sustain reads > 1GB/s, faster then any SATA SSD, and this is on spinning rust.
With the 64GB of ram and the L2 cache, I get random access performance comparable with NVMe SSDs for frequently accessed files (os, apps, etc)

Is local NVMe faster? yes. Is it as cost effective per GB of storage and offers data redundancy? no.