Hot Spare on EVA-5000

[Chuck Ciesinski]

To all,

Im sure this has been asked before, but how many 'Hot Spares' can I put into an EVA5000 utilizing a mix of 72 and 146 GB drives? I'm also looking for any statistics on the I/O transfer rate if anybody is willing to share?

Thanks in advance,

Chuck Ciesinski

[Uwe Zessin · Accepted solution]

The EVA does not use dedicated spare disk drives - it uses 'protection capacity'. There are 3 levels:

0 = no capacity reserved
1 = 2x size of largest disk in disk group
2 = 4x size of largest disk in disk group

Just imagine that you take the capacity that is provided by the 'space disks', rotated 90 degrees and equally distributed over all disks in a disk group.

Now, even if you set the so-called 'protection level' to "0", the EVA can still rebuild data after a disk loss, as long as there is enough free space in a disk group. The 'protection level' is just a highwater mark that prevents you from accidently assigning this space to any virtual disk.

[Chuck Ciesinski]

Uwe,

Thank you for such a quick and informative response. I can now ask some more intelligent questions...

Chuck

[Peter Mattei]

Chuck
There are some interesting whitepapers available on
http://h18006.www1.hp.com/storage/arraywhitepapers.html
One particular talks about EVA5000 performance in an Exchange 2003 environment
http://h18006.www1.hp.com/storage/arraywhitepapers.html

Cheers
Peter