RAID Design

[basem]

Hi Guys,

I am a new to Storage World..

I am obligated to set design for new SAN (HP MSA 1040 g4, this SAN consists of 24 Disks) that will serves for VMware virtualization environment...

I am going to divide the 24 HDDs as following:

all the Disks will be 1.8 TB, 10K, 2.5-inch

- 3 x LUNs RAID 5 (consists of 4 Disks) so each LUN size will be 5.4 TB, these LUNs will be for silver workload...
- 2 x LUNs RAID 10 (consists of 4 Disks) so each LUNs size will be 3.6 TB, these two LUNs for golden workload (Databases and Critical business Virtual Machines)...
.
the remaining Disks (4 Disks) will be as Hot Spare...
.
I need your opinion...

Thank you in advanced

 

[frowertr]

I don't see the reason not to do a single big ol'e RAID 10 here (including the 4 extra drives you are wanting to keep for hot spares). It will give you decent speeds with all those spindles working in conjunction with one another and it will give you superior fault tolerance and rebuild time when compared to RAID 6.

You need to avoid RAID 5 all costs.

http://www.smbitjournal.com/2012/11/one-big-raid-10-a-new-standard-in-server-storage/
http://www.smbitjournal.com/2012/07/hot-spare-or-a-hot-mess/
http://www.smbitjournal.com/2015/03/practical-raid-choices-for-spindle-based-arrays/

Edit: You will lose 1.8TB of useable space going with OBR10 versus the way you are wanting to set it up. But honestly, you wouldn't use RAID 5 on mechanical drives with this size of an array nowadays anyway in a production system. So your amount of useable space will come down if your forgo RAID 5 regardless of what other RAID configuration you choose.

 

[dave_the_nerd]

Don't split your spindles up into penny packets. It chokes IOPS. You can slice virtual LUNs or datastores out of a single big pool.

I'd be surprised if HP didn't have some best practices recommendations or defaults to implement as far as storage pooling and disk allocation goes. I know if you get a Compellent box, they basically tell you NOT to meddle around with manually allocating disks, and that the software is smarter than you.

http://h20566.www2.hpe.com/hpsc/doc/public/display?docId=emr_na-c04220794&docLocale=en_US

So you should read that and contact HP.

There are, from what I've overheard, diminishing performance returns for larger stripes - we* generally recommend customers stick to 12-disk RAID groups. So following that advice, a pair of 12-disk RAID6, or a 12-disk RAID6 and a 12-disk RAID10 combined into a single storage pool, seems like your best bet to me. (The HP box apparently supports some kind of storage tiering, if you sprung for the license to enable that feature, so you should be able to make effective use of a "slow" RAID group and a "fast" RAID group.)

*I do not work for HP, but we also sell SANs.

 

[master_shake_]

redundancy > space afaic.

2 raid 60's

 

[basem]

In fact, I tend to go with your opinion, but, that means, all of VMs' workload will hits against one LUN, this is my concerns...

I don't see the reason not to do a single big ol'e RAID 10 here (including the 4 extra drives you are wanting to keep for hot spares). It will give you decent speeds with all those spindles working in conjunction with one another and it will give you superior fault tolerance and rebuild time when compared to RAID 6.

You need to avoid RAID 5 all costs.

http://www.smbitjournal.com/2012/11/one-big-raid-10-a-new-standard-in-server-storage/
http://www.smbitjournal.com/2012/07/hot-spare-or-a-hot-mess/
http://www.smbitjournal.com/2015/03/practical-raid-choices-for-spindle-based-arrays/

Edit: You will lose 1.8TB of useable space going with OBR10 versus the way you are wanting to set it up. But honestly, you wouldn't use RAID 5 on mechanical drives with this size of an array nowadays anyway in a production system. So your amount of useable space will come down if your forgo RAID 5 regardless of what other RAID configuration you choose.

 

[basem]

Thank you very much for this valuable ideas...

Don't split your spindles up into penny packets. It chokes IOPS. You can slice virtual LUNs or datastores out of a single big pool.

I'd be surprised if HP didn't have some best practices recommendations or defaults to implement as far as storage pooling and disk allocation goes. I know if you get a Compellent box, they basically tell you NOT to meddle around with manually allocating disks, and that the software is smarter than you.

http://h20566.www2.hpe.com/hpsc/doc/public/display?docId=emr_na-c04220794&docLocale=en_US

So you should read that and contact HP.

There are, from what I've overheard, diminishing performance returns for larger stripes - we* generally recommend customers stick to 12-disk RAID groups. So following that advice, a pair of 12-disk RAID6, or a 12-disk RAID6 and a 12-disk RAID10 combined into a single storage pool, seems like your best bet to me. (The HP box apparently supports some kind of storage tiering, if you sprung for the license to enable that feature, so you should be able to make effective use of a "slow" RAID group and a "fast" RAID group.)

*I do not work for HP, but we also sell SANs.