MSA Storage
cancel
Showing results for 
Search instead for 
Did you mean: 

MSA 1040 Raid & Tiering config + D2700

 
SOLVED
Go to solution
Spartanmk2
Occasional Contributor

MSA 1040 Raid & Tiering config + D2700

Hello all,

I'm setting up a 1040 at a remote site that will deal mostly with a very small vcenter environment (2hosts >5 VMs) and VM replication from our main site.

I currently have 8x600gb 10k SAS drives which Im thinking of setting up in a raid 10 (virtual class) configuration, 2x2 in pool A/B and used for the VM's that host this remote site (SRM Appliance, Fileserver, DC etc.).

I also have a D2700 disk shelf with 25x1.2TB 10k SAS drives which are intended as the storage for the replicated VMs from our main site. I was thinking of creating a 12 disk raid6 (virtual class) for pools A/B with one global spare.

Will having two different raid types on each controller cause performance issues? I know in the pdf it says to keep it balanced on both controllers, but with this setup I'm unsure how to approach disk groups with different disk sizes - and I'm unfamiliar with the tiering setup. Our main site was simple since we have all the same disk size/speed and I balanced both controllers with same raid +SSD for cache.

Also, if a 1.2TB drive is set as the global spare, and a disk from my raid10 fails, will the MSA use the 1.2TB disk and only allocate 600gb and waste the other half? If so, is there a way to specify it only be used on my raid 6's? 

 

4 REPLIES 4
Solution

Re: MSA 1040 Raid & Tiering config + D2700

1st of all Automated Tiering concept works with different drive types like SSD, SAS and MDL SAS. In your case all are SAS drives so this is anyway not applicable.

Now coming to your configuration, Global spare get set at the System level which means if you set one 600GB and one 1.2TB drive as Global spare and one 600GB drive failed. Then any one of the global spare may kick in and we can't control this but if one 1.2TB drive failed then obviously 1.2TB drive will kick in as Global spare. Rule is system look for same type and same size or bigger size drive compare to the drve which actually failed. 

So in your case if you plan to have 4 x 600 drive as RAID1 disk group and 12 x 1.2TB drive as RAID6 disk group . Both same in both Pools. One 1.2TB drive as Global spare. Then as explained above if any 600GB drive failed then 1.2TB global spare will kick in and after reconstruction completed 600GB space will be wasted.

Coming to performance issue, yes it's not recommended to have different RAID type for same type of drives.  If a disk group has a different capacity, then the number of pages stored on it will eventually differ compared to other disk group in that Tier, and would therefore also lead to unpredictable performance.

As Pages are striped across all the disk groups in that Tier, disk groups with fewer drives will underperform compared to the others, equally disk groups with more drives would get a little performance boost, which although not necessarily a bad thing in itself equates to reduced predictability.

 

Hope this helps!
Regards
Subhajit

I am an HPE employee

If you feel this was helpful please click the KUDOS! thumb below!

************************************************************************


Accept or Kudo
Spartanmk2
Occasional Contributor

Re: MSA 1040 Raid & Tiering config + D2700

Thank you for the response, Subhajit.

Ok so tiering is not going to be in this configuration, and I should not set a global spare and leave the 1.2TB disk as dynamic? There's no check box or anything like that which designates it dynamic or does simply not having a global spare enable it?

I'm still a little uncertain as to what raid I should go with, they say to have balance between the A/B pools, but with these 600gb and 1.2TB disks its throwing my thought off and I'm constantly going back to the drawing board. What you would recommend?

Re: MSA 1040 Raid & Tiering config + D2700

There is no concept of dedicated spare in Virtual Array. So whether you configure Global spare or Dynamic Spare feature both will be at the system level.

So if your system having same type different size drives then always there is a chance of space wastage when smaller size drive failed and higher size drive configured as spare.

That is why we always suggest to have same type and same size drives to get optimum performance.

Now coming to balancing to load accross the pools that depends up on your business requirement and applications.

 

Hope this helps!
Regards
Subhajit

I am an HPE employee

If you feel this was helpful please click the KUDOS! thumb below!

**************************************************************************


Accept or Kudo
Highlighted
Spartanmk2
Occasional Contributor

Re: MSA 1040 Raid & Tiering config + D2700

Alright, thank you. I appreciate your time and responses. I'll leave the spare as is.