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

[Alzhy]

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 .

[Uwe Zessin]

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]

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

[The Spartan]

Link I had spoken of -

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=899892&admit=-682735245+1172566127298+28353475

[Uwe Zessin]

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]

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!

[Uwe Zessin]

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

[Peter Mattei]

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

[Peter Mattei]

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

[Alzhy]

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?