Storage spaces mirror fault tolerance vs raid 10

OnSeATer

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Jul 31, 2016
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Hi ... on the off chance that anyone is following this thread or comes across it on a google search I wanted to post a quick followup.

Did a proof of concept consisting of:

- "Performance tier" of 2x Intel S3500 SSDs, directly connected over SATA
- "Capacity tier" of 2x HP HDD, configured as a single RAID1 logical volume behind the LSI raid controller on a Supermicro X9DRD board

The MediaType of the LSI Raid logical volume was set to HDD using the Set-PhysicalDisk command.

On the Performance tier, the ResiliencySettingName was set to Mirror
On the Capacity tier, the ResiliencySettingName was set to Simple (which it had to be, since Windows only sees the one logical drive)

A windows volume was created via New-Volume, using tiers, with ReFS as the filesystem.

Performance on CrystalDiskMark on this new volume was consistent with the performance of 2x S3500 SSDs, suggesting that things were more or less working as expected. I have not yet done any more detailed testing / benchmarking but was sufficiently encouraged that I am moving ahead with this approach at a somewhat larger scale with NVMe drives as the Performance tier and a Raid 6 array of HDDs as the Capacity tier. Happy to post updates if anyone is interested.
 

Connorise

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Mar 2, 2017
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US. Cambridge
I've been considering a move to Windows Storage Spaces (single box, not S2D), with 8 HDD in a 4-column mirror configuration.


Is that correct? If so, how does anyone get comfortable with that? I know rebuild time should be shorter than in a RAID5 array, but still, it seems like playing with fire. I've seen posts on this site from folks that have used Storage Spaces in massive deployments so there must be a way. Parity space performance is poor enough that it doesn't really seem like an option.

Any advice would be much appreciated.
>My thought had been that this would provide fault tolerance comparable to RAID 10 ... worst case tolerating 1 failure, best case tolerating 4 failures. But in doing more reading it seems that no matter how many columns, mirrored storage spaces won't tolerate more than one drive failure.

Not rly, SS will provide you with "like" RAID 10 replication. In reality, SS in the 8HDDs configuration will be able to tolerate 1 drive failure and not more. On the other hand, HW will provide you with possibility to lose 4 drives (if you are lucky enough)