topic Raid in Disk Enclosures

Raid

Maria Regev — Thu, 23 Jun 2005 10:28:46 GMT

Hi,

I have a system Proliant dl380, smart array 5i.
and a raid0 with 4 disk (146 GB). I would like to convert the raid0 to raid5 without data lost.
It's possible?

Thanks

Re: Raid

Jefferson Humber — Thu, 23 Jun 2005 10:46:28 GMT

Maria,

A 4 disk stripe set is very risky, if one disk dies you loose the lot.... no wonder you want to migrate to RADI5.

One thing to remember is the you will loose 25% of available free space (with 4 disks), since under RAID5 one of the disks will become a parity disk. Also disk writes will be slower, because of the parity overhead.

http://h200001.www2.hp.com/bc/docs/support/SupportManual/c00257511/c00257511.pdf

The document implies RAID migrations can be done on the fly, but doesn't state whether you can go from 0 -> 5. A backup of your data would also be essential though, just in case anything went wrong.

I would personally ensure I also had the latest F/W installed on the Smart Array controller before performing such a task, just a personal preference.....In case there's a bug in the old version.

Jeff

Re: Raid

Jefferson Humber — Thu, 23 Jun 2005 10:53:36 GMT

Actually I think it does say something about this scenario in the document (Page 7);

'The
following situations would require additional drive space: changing RAID 0 to RAID 1, 5, or RAID
ADG; or changing RAID 5 or RAID ADG to RAID 1.'

I assume it keeps the logical size the same, so an extra disk would be needed for parity purposes.

Jeff