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RAID 1 with SSD(master)+HDD(mirror)?

Last response: in Storage
January 21, 2011 8:07:27 PM

As the title says, I want to know if its possible and if it makes sense to use Raid 1 (redundancy) with a SSD as the master and HDD as the mirror. Since the SSD is much faster will this cause write problems to the HDD.

Specifically im looking at

Also if any one has ever actually done this and could share any useful information. THANKS!

More about : raid ssd master hdd mirror

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a b G Storage
January 21, 2011 8:25:35 PM

You don't want to RAID an SSD and a regular hard drive. The SSD will be slowed down to the HDD"s read/write speed. In a RAID 1, the drives stay synchronized. All reads and writes are done synchronously. You should always use identical drives in RAID arrays.
February 18, 2013 8:28:41 AM

This may physically work with your RAID controller however you won't get good write performance (as pointed out by mavrovur) unless you have write caching enabled in the controller (or the OS/application). I would guess that the read performance would be good if the controller can spot the absence of a queue or latency for the SSD device.
March 13, 2013 8:22:33 AM

RE: SSD mirror with a mechanical hard-drive.

An end-user asked me to install this type of setup.

I did alert the end-user that it would likely cause an issue. The workstation this setup is installed in is critical - so I didn't have too many opportunities to further research what the errors were in the first place, I merely wanted to point out that in my scenario, it was not a good idea to mirror an SSD with a mechanical hard-drive.

The end-user originally had two mechanical hard-drives mirrored using the on-board MB's RAID controller. (Intel) Changed out one of the mechanical drives with an SSD - (keeping the mirror going) no complaints from the RAID controller - BUT, after a week, the RAID controller complained the SSD lost CRC and moved the SSD to off-line.

I took out the SSD, (ran a quick check/fix-disk) and the SSD is fine - and I'll be mirroring 2 SSDs vice one mechanical and one SSD.

I will update this post if my result may have been from a defective SSD vice, what I feel is the real issue, that the SSD is/was too fast for CRC.