8 Drives: 2x RAID 5 vs 1x RAID 6

[akashkrishnan]

RAID Card: LSI MR9280-24i4e

Drives: 8x WD Blue 6 TB

Purpose: store and read files large files (5 MB - 50 GB)

Daily Read Usage: 100 GB

Daily Write Usage: 100 GB

 

Question: should I create two RAID 5 arrays spanned together into a single volume or one RAID 6 array?

 

On another note: I have a 24 bay NAS, all filled with WD Blue 6 TB drives---yes, I wanted WD Reds, but due to my usage and cost, and bet on the WD Blues. What's the best setup for a single volume on Windows Server 2012 R2? I want to maximize storage first, then redundancy, then read performance.

[tt2468]

One raid 6.

[akashkrishnan]

That's what I'm leaning towards.

 

On another note: I have a 24 bay NAS, all filled with WD Blue 6 TB drives---yes, I wanted WD Reds, but due to my usage and cost, and bet on the WD Blues. What's the best setup for a single volume on Windows Server 2012 R2? I want to maximize storage first, then redundancy, then read performance.

[leadeater]

19 minutes ago, akashkrishnan said:

That's what I'm leaning towards.

 

On another note: I have a 24 bay NAS, all filled with WD Blue 6 TB drives---yes, I wanted WD Reds, but due to my usage and cost, and bet on the WD Blues. What's the best setup for a single volume on Windows Server 2012 R2? I want to maximize storage first, then redundancy, then read performance.

What RAID card do you have and does it have the BBU/Cache Vault?

 

Since you are using Server 2012 R2 I would actually use Storage Spaces rather than hardware RAID unless your RAID card is very good. Since you are primarily wanting storage capacity hardware RAID would be more appealing to you anyway. Storage Spaces parity configuration performance is horrific.

[akashkrishnan]

3 minutes ago, leadeater said:

What RAID card do you have and does it have the BBU/Cache Vault?

 

Since you are using Server 2012 R2 I would actually use Storage Spaces rather than hardware RAID unless your RAID card is very good. Since you are primarily wanting storage capacity hardware RAID would be more appealing to you anyway. Storage Spaces parity configuration performance is horrific.

LSI MR9280-24i4e

 

I was thinking of combining multiple RAID arrays together in software to create the actual volume.

[leadeater]

2 minutes ago, akashkrishnan said:

LSI MR9280-24i4e

 

I was thinking of combining multiple RAID arrays together in software to create the actual volume.

I wouldn't, see the failure of the LMG SSD server for why .

 

A 23 disk RAID 6 + 1 Hot Spare will do the job just fine. If your not keen on that then 2x 11 disk RAID 6 + 2 global host spares. Do you actually need the storage as a single volume? You can use DFS to give a single name space you can map to that contains real shares the exist in multiple different volumes, far as the client computer can tell it's all one share.

[akashkrishnan]

What I meant by using software was creating a spanned volume with 3x 8-disk RAID 6 virtual disks---that way, if a RAID array fails, only the data in that RAID array will be lost from the volume.

 

I'll look into DFS to see if it would work as well as or better than a spanned volume---I'm guessing it would. Thanks!

[dalekphalm]

9 hours ago, akashkrishnan said:

What I meant by using software was creating a spanned volume with 3x 8-disk RAID 6 virtual disks---that way, if a RAID array fails, only the data in that RAID array will be lost from the volume.

 

I'll look into DFS to see if it would work as well as or better than a spanned volume---I'm guessing it would. Thanks!

You're describing a RAID 60 array here. There's nothing wrong with that, and in theory, it will provide even better protection vs one giant RAID 6 array.

 

Does your RAID card have a Memory Cache and Battery Backup Unit? If not, buy them.

[akashkrishnan]

10 hours ago, dalekphalm said:

You're describing a RAID 60 array here. There's nothing wrong with that, and in theory, it will provide even better protection vs one giant RAID 6 array.

 

Does your RAID card have a Memory Cache and Battery Backup Unit? If not, buy them.

Yes, I have enabled the write-back policy with a BBU.

 

A spanned volume in Windows is actually just a concatenation of drives, where the first drive in the spanned volume is filled first, then the second, etc. With a spanned volume in Windows, if one drive were removed and inserted it into another system, the files and the respective directory tree would be preserved and accessible to the other system.

 

I am not entirely sure if a RAID 60 in my situation would provide more performance than three spanned RAID 6 arrays, because I only have one RAID card and can't use striping at the software level to take advantage of the bandwidth three RAID cards would provide. Additionally, RAID 60 would provide less protection than three spanned RAID 6 arrays, so I am currently set on the latter approach but could be convinced otherwise.

 

Regarding DFS, I was unable to find a way to accomplish what I was looking for, which is described well in the following article: https://romanrm.net/mhddfs.

[alex75871]

RAID 6. It is entirely possible to lose 2 drives from 1 RAID 5 pool - happened to my friend