topic Re: Add 300 GB Disks to EVA5000 in Disk Enclosures

Add 300 GB Disks to EVA5000

LJM_1 — Tue, 03 Apr 2007 11:36:52 GMT

VCS 3028

I need to expand the Default Disk Group, then replace the small capacity (72 GB) drives.

Group currently consists of 120 HDDs (15 TB) of various sizes/models -

BD14656ABC HP0A
BF07255B2C HP05
BD14658225 HP01
BD14655B2A HP05
BD1465822C HP02

Anyone seen issues with adding 300 GB FC HDDs (BD30058232 HP04) to a similiar array?

Anything to watch for?

How does the levelling process impact peformance?

Are there best practices when expanding Disk Groups? - ie group similiar disks, maximum number of disks in a group, etc...

Thanks!

Re: Add 300 GB Disks to EVA5000

Ivan Ferreira — Tue, 03 Apr 2007 14:54:24 GMT

Anyone seen issues with adding 300 GB FC HDDs (BD30058232 HP04) to a similiar array?

We had no problems to add 300 GB disks to our EVA5000 and mix them with current 146 GB disks.

Anything to watch for?

Probably, you will need to set the protection level to none, until leveling is finished, because when you add 300 GB disks, and your protection is single, 600 GB of space will be used as protection, if your protection is double 1200 GB of space will be used as protection.

All disks firmware versions should be updated.

How does the levelling process impact peformance?

You should have leveling running some times, for example, when a disk fail. The performance inpact will be similar.

Are there best practices when expanding Disk Groups? - ie group similiar disks, maximum number of disks in a group, etc...

Yes. Check the EVA best practices. Check my last post here:
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=945627

The document is attached in that post.

Re: Add 300 GB Disks to EVA5000

pswma2 — Thu, 05 Apr 2007 01:52:12 GMT

Hi,
if you have some space free in your disk group I would suggest to ungroup as many 72 GB disks as possible before adding 300 GB. Using mix of 72, 146 and 300 GB disks makes leveling really slow - 5 to 7 days (on EVA-5000 with 148 HDDs). The levelling process itself is a background process so you will not get visible performance impact on your servers.

Re: Add 300 GB Disks to EVA5000

LJM_1 — Thu, 05 Apr 2007 09:32:41 GMT

I added one 300 GB disk to the existing DG (Default) yesterday. 43% levelled after almost 24h.

So far no reports of performance issues.

The Default DG currently at 450 GB raw Vraid1 capacity. With snapshots that occur, this can drop to 250-300 GB until the snapshots are unpresented.

I'm planning to add 3 more 300 GB drives before I start pulling the 72 GB HDDs.

Re: Add 300 GB Disks to EVA5000

Uwe Zessin — Thu, 05 Apr 2007 13:34:43 GMT

I would always add new disk drives in pairs. Otherwise, the EVA might marry a smaller disk with a 300GB one.

As far as I can tell, you are then restricted to the capacity of the smaller disk drive of this couple. If that happens a few times, you can loose LOTS of storage.

Re: Add 300 GB Disks to EVA5000

Tom O'Toole — Fri, 06 Apr 2007 11:38:36 GMT

You mean lose lots of capacity.

Re: Add 300 GB Disks to EVA5000

Uwe Zessin — Sat, 07 Apr 2007 13:25:51 GMT

can we agree on storage capacity ?

;-)

Re: Add 300 GB Disks to EVA5000

Tom O'Toole — Tue, 10 Apr 2007 10:43:17 GMT

Sorry I screwed up my own pedantic correction:-)

I was referring to the use of the word "loose" for "lose", not the words storage vs. capacity.

Re: Add 300 GB Disks to EVA5000

Uwe Zessin — Tue, 10 Apr 2007 12:56:42 GMT

Oh, I see.
Well, thank you for helping me to improve my English - it is really appreciated.