HPE MSA 1050 Extend Pool A, add SSD cache

[_Paolo]

Hi,

I have a MSA 1050 with VE100R002 firmware configured as below:
- Pool A -> DiskGroup1 -> 4 x 300GB 10K SAS RAID5
- Pool A -> DiskGroup2 -> 3 x 300GB 10K SAS RAID5
- Global Spare -> 1 x 300GB 10K SAS
I would need extend Pool A capacity. Is it possible to add a single 300GB 10K SAS disk to one of the DiskGroups? If I remember correctly, in the P2000 G3 it was possible to extend the volumes by adding single disks.
In the MSA 1050 manual I find instead that it is need to add another DiskGroup in RAID.

Moreover, I would like to consider adding an SSD for cache. How can I calculate if I would really get a high increase in storage performance additing SSD cache?
Thanks you a lot
Paolo

[SUBHAJIT KHANBARMAN_1]

Yes it's not possible to expand any existing Virtual DIsk Group. Only option to increase space for any Pool is to add new VDG. Otherwise take data backup. Then delete all and re-create. Then restore from backup.

Coming SSD, yes you can create Read cache but that will help to improve read performance only. You should consider SSD use as seperate tier or Performance tier so that you can get benefit of both read and write operation.

Hope this helps!
Regards
Subhajit

I am an HPE employee

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

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[Cali]

Hi,

add on to SUBHAJIT KHANBARMAN_1.

Read Cache is for free and you need only one SSD.

Performance Tiering needs a License and Two SSD.

Size 5 - 10% for Cache is a good rule.

@SUBHAJIT KHANBARMAN_1 

Is the MSA Flash Advisor still available?

[_Paolo]

Thank you very much for the answers.
I would like to know if there is a IOPS performance difference between configuration a) and configuration b) below:
a) Pool A -> DiskGroup1 (4 x 300GB 10K SAS RAID5) + DiskGroup2 ( 3 x 300GB 10K SAS RAID5) = 1500 GB
b) Pool A -> DiskGroup1 (7 x 300GB 10K SAS RAID5) = 1800 GB
Does configuration b) allow more space available and best IOPS performance?

If I add a single 400GB SSD as a cache, does this cache allow the MSSQL DBs hosted in the Pool A volumes performance to be greatly improved? 70% of works of these DBs are read-only.

Otherwise I could buy 3 x 400GB SSD, delete and re-create everything as follows:
- Pool A -> DiskGroup1 (8 x 300GB 10K SAS RAID5) = 2100 GB
- Pool B -> DiskGroup1 (2 x 400GB SSD RAID1) = 400 GB
- Global Spare -> 1 x 400GB SSD
Is it possible to use 1 x 400GB SSD as Global Spare for both SSD DiskGroup and 300GB 10K SAS DiskGroup?
Thanks a lot

Paolo

[SUBHAJIT KHANBARMAN_1]

If your requirement is more of read operation then instead of buying 3 SSDs buy 3 x 300GB SAS drives and below approach will be good,

Pool A -> DiskGroup1 (9 x 300GB 10K SAS RAID5) = 2400 GB

Global Spare-> 1 x 300GB 

Read Cache-> 1 x 400GB SSD

Why because at the time of creating RAID5 VDG you need to keep in mind data chunklets should follow power of 2 rule so if you select RAID5 with 7 drives means 6+1 but that will not meet the rule. It should be total drives 3, 5 or 9 so that data chunklets will be 2, 4 or 8

Another thing whatever approach that you select please keep in mind that drive replacement need to happen with same type of drive and size can be equal or big. So SSD drive can't be use as SAS drive spare drive.

Hope this helps!
Regards
Subhajit

I am an HPE employee

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

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

[_Paolo]

Thanks again for the answers SUBHAJIT KHANBARMAN_1,

Could you tell me if there is difference in IOPS performance between the following two configurations?

a) Pool A -> DiskGroup1 (4 x 300GB 10K SAS RAID5) + DiskGroup2 (3 x 300GB 10K SAS RAID5) = 1500 GB
b) Pool A -> DiskGroup1 (7 x 300GB 10K SAS RAID5) = 1800 GB

Thanks

Paolo

[SUBHAJIT KHANBARMAN_1]

I have checked IOPs with 600GB 15K drive as my tool starts with this only. Also I have taken total drives as 3 or 5 or 9 because of keeping power of 2 for data chunklets in mind.

Pool A
----------
VDG1 (3 x 600GB 15K SAS drive)
VDG2 (3 x 600GB 15K SAS drive)
VDG3 (3 x 600GB 15K SAS drive)

Total IOPs -> 3145

Pool B
---------------

VDG1 (9 x 600GB 15K SAS drive)

Total IOPs -> 3145

Hence if no of drives same as well as similar disk type and size then IOPs should be same Pool wise because your volume will be distributed accross all VDG in the Pool. I am assuming no of volumes same per Pool and same application running when doing the comparison.

Hope this helps!
Regards
Subhajit

I am an HPE employee

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

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

[_Paolo]

Thanks for the reply SUBHAJIT KHANBARMAN_1.
I just don't understand how 9 x 600GB 15K SAS RAID5 can give 3145 IOPS. According to the IOPS calculators that I find on the web, I have a maximum total of 1500 IOPS.
Thanks

[SUBHAJIT KHANBARMAN_1]

There are lot of factor matters here,

-> type of drive

-> make and model of drive

-> rpm speed of drive

-> RAID of the disk group where drives participated

-> IO size

-> Random or sequential read/write

-> read/write percentage

You are going with standard for example, if any 15K SAS drive max IOPs value 180 then for 9 drives it will be (9 x 180) = 1620 

Doing performance measurement not easy, it needs lot of factors keeping in mind. I will not go in details in public forum.

Hope this helps!
Regards
Subhajit

I am an HPE employee

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

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