topic Re: Question about EVA systems in Disk Enclosures

Question about EVA systems

nemanja.stosic — Wed, 18 Feb 2009 12:37:59 GMT

Hi to all,
If I have an EVA system, 4 disk enclosures. All the disks are 147GB, in one disk group. If I present 10GB vdisk, to one host, how will EVA system pick up the place from which disk to take that? Is it going to take that place only from one disk, or from 2 or more? General question is, if the vdisk size is smaller that one physical disk, is it going to take tha place only from one disk?

Thanks

Re: Question about EVA systems

Víctor Cespón — Wed, 18 Feb 2009 12:56:35 GMT

For performance reasons the EVA distibutes the vdisk space among all disks on the disk group.

Say you have 50 disks and you create a 100 GB vdisk in vRAID 1. The EVA will take 4 GB from each disk, writing each data segment on two disks.

Re: Question about EVA systems

Uwe Zessin — Wed, 18 Feb 2009 17:37:15 GMT

The virtualization is so fine-grained that that data of a virtual disk with 1 GigaByte (smallest possible size) can be distributed across all 240 disk drives (maximum number of disks possible on _large_ EVA systems).

Re: Question about EVA systems

Brandon Madanjit — Fri, 20 Feb 2009 09:51:51 GMT

EVA's are an amazing piece of Hardware. For instance, if I have an EVA with a disk group of 10 x 300GB drives, and I created a vdisk of 300GB, the EVA would distribute this vdisk over all 10 (300GB) disks. Approximately 30GB will be assigned to each disk, therefore distributing your vdisk accross every drive in the disk group resulting in a lower overhead and high tolerance against failure.

Re: Question about EVA systems

nemanja.stosic — Fri, 20 Feb 2009 10:30:56 GMT

Thanks, for quick answers. I have got one more question.
Are 300GB disks suported on EVA 5000 vcs4, we have upgraded our contrrolers to that they can work as active/active. And what is the max storadge supported by EVA 5000.

Thanks Nemanja

Re: Question about EVA systems

Uwe Zessin — Fri, 20 Feb 2009 10:41:26 GMT

The EVA5000 can 'map' 32 SoftWare / 35 HardWare TeraBytes. That capacity can exist in form of virtual disks, clones, containers and snapshots. So in some cases you CANNOT utilitze the whole 'raw' capacity.

Here is a customer advisory:
c00838520 - Advisory: HP StorageWorks Enterprise Virtual Array EVA3000 and EVA5000 Usable Capacity Limited to 35 TB

http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?lang=en&cc=us&objectID=c00838520&prodTypeId=12169&prodSeriesId=3664763

Re: Question about EVA systems

Víctor Cespón — Fri, 20 Feb 2009 10:43:46 GMT

List of supported disks by firmware version:

http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?lang=en&cc=us&objectID=c01114153&jumpid=reg_R1002_USEN

Also, on the VCS 4.100 release notes:

http://bizsupport2.austin.hp.com/bc/docs/support/SupportManual/c01608153/c01608153.pdf

So the maximum size per disk is 500 GB. And the maximum number of disks is 240.