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EVA 5K @ VCS 3.028 - Any Limitation on DiskGroup Size?

Alzhy
Honored Contributor

EVA 5K @ VCS 3.028 - Any Limitation on DiskGroup Size?

We have an all FATA (500GB) drives that used to be 4 enclosures (~48 disks) and ~20TB total capacity. We've recently added 2 more enclosures (~ 24 disks). The Diskgroup capacity increased to arounf 30TB BUT we're not able to carve VDISKS... the carvable VDISK capacity (any level) remains at less than 2TB despite the diskgroup showing the available capacity.

BTW the EVA we have are fully maxed out - 240 Disks total in 3 Diskgroups - 2 FC DIskgroups and our mega FATA diskgroup composed of 72 Disks where we are having carving issues.


Anyone? HP is investigating .

Hakuna Matata.
13 REPLIES
Uwe Zessin
Honored Contributor

Re: EVA 5K @ VCS 3.028 - Any Limitation on DiskGroup Size?

Several things are possible:

- when you attempt to create a new virtual disk, Command View EVA shows the maximum possible size for the next vdisk. So it will show 2047.99GB, even if there is more space available in the disk group.

- the EVA5000 has a presentation limit of 32 TB. Maybe you alrady have Vdisks and/or snapshots in that range.
.
The Spartan
Trusted Contributor

Re: EVA 5K @ VCS 3.028 - Any Limitation on DiskGroup Size?

Hi Nelson,

I had read somewhere that the maxiumum size of presentable Vdisk is 2TB. Limitation is due to VCS firmware.

I shall try to provide the link if I find the same.

Regards,
The Spartan
If you are keen to win, you should be willing to lose.
The Spartan
Trusted Contributor

Re: EVA 5K @ VCS 3.028 - Any Limitation on DiskGroup Size?

Link I had spoken of -

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=899892&admit=-682735245+1172566127298+28353475
If you are keen to win, you should be willing to lose.
Uwe Zessin
Honored Contributor

Re: EVA 5K @ VCS 3.028 - Any Limitation on DiskGroup Size?

It is also a limit in the SCSI protocol's use of 10-byte command descriptor blocks.
2TB = 2**32 blocks a' 512 byte.
.
Alzhy
Honored Contributor

Re: EVA 5K @ VCS 3.028 - Any Limitation on DiskGroup Size?

Guys, I think you're not getting fully our issue. So here it is again.

We have a Diskgroup - now composed of 72 FATA500GB Drives. It started out as 48 drives with a total capacity of ~20TB. We expanded it by another 24 drives lately so we should now have more or less ~10TB available.

We are aware that the maximum "carvable" VDISK (any RAID level) is 2TB (2048GB). So whenever we carve new VDISKS and as long as we have available capacity - the "carvable" VDISK capacity should remain at 2TB until space is almost exhausted - right?

Well that's the issue. We still have about ~9TB free on this diskgroup AND after carving a few VDISKS - the "carvable" VDISK capacities (accross levels) do not return to 2TB! So in effect - we cannot use the added capacity!


Hakuna Matata.
Uwe Zessin
Honored Contributor

Re: EVA 5K @ VCS 3.028 - Any Limitation on DiskGroup Size?

Well, have you considered my second point
(total capacity of all vdisks <= 32 TB)?
.
Peter Mattei
Honored Contributor

Re: EVA 5K @ VCS 3.028 - Any Limitation on DiskGroup Size?

Hi Nelson

The 32TB is the sum of all virtual blocks allocated in the EVA5000.

So the 32TB max include:

1. All configured Virtual Disks (independent of whether they are presented or not)

2. All Snapshots with the full capacity even if it's a demand-allocated Snapshot (also independent of whether they are presented or not)

3. All CA log space allocated


Cheers
Peter
I love storage
Peter Mattei
Honored Contributor

Re: EVA 5K @ VCS 3.028 - Any Limitation on DiskGroup Size?

And to cover all limits, the max DR Group size supported is 16TB!

This will not impact you since in VCS 3.028 a DR Group can only have 8 Vdisks; a Vdisk can be max 2TB. 8*2TB = 16TB

With VCS 4.xxx and all XCS versions a DR Group can contain 32 Vdisks but still "only" 16TB.

Cheers
Peter
I love storage
Alzhy
Honored Contributor

Re: EVA 5K @ VCS 3.028 - Any Limitation on DiskGroup Size?

And it appears we sure have more than 32TB of presented VDISKs already.

So why did HP still oblige to sell us 2 shelffulls of FATA500GB drives then -- the fact that they were aware of our current EVA configuration!?

Can you point me to documentation that states total VDISK capacity is limited to 32TB? Is this a Firmware limitation for all VCS 3.X family? Does VCS 4.x resolve this issue?
Hakuna Matata.
Alzhy
Honored Contributor

Re: EVA 5K @ VCS 3.028 - Any Limitation on DiskGroup Size?

Above post should read:

.. then why did HP sold us EVA capacity that they would have red-flagged before-hand will not be fully usable in our EVA configuration ?"
Hakuna Matata.
Peter Mattei
Honored Contributor

Re: EVA 5K @ VCS 3.028 - Any Limitation on DiskGroup Size?

I know, it is not documented very prominently!!

See the HP StorageWorks Enterprise Virtual Array 3000 and 5000 configuration best practices white paper; page 8 on
http://h71028.www7.hp.com/ERC/downloads/5982-9140EN.pdf

The limitation is not the VCS version but the available amount of policy memory in the EVA5000 controllers.

Sorry, I am only the messenger
Peter
I love storage
Ryan_11
Advisor

Re: EVA 5K @ VCS 3.028 - Any Limitation on DiskGroup Size?

Hi Nelson,

We have just run into the same issue after upgrading from 27TB to approx 60TB at both production and DR. I would just like to know if HP came to the party and resolved your issues by upgrading the controllers to EVA8K's or what their final solution was. This is just not acceptable.

Regards
Alzhy
Honored Contributor

Re: EVA 5K @ VCS 3.028 - Any Limitation on DiskGroup Size?

A disk group can be as large as your 500GB Fata Drives - BUT, it seems you can only carve VDISKs capacity up to ~ 32TB using whatever RAID level.

No solution yet to this problem and HP Sales sometimes would not warn you you're buying capacity that you'll really end up not able to use.

Hakuna Matata.