topic Re: Strange Disk Problem in MSA Storage

Strange Disk Problem

CA878053 — Wed, 18 Dec 2002 22:52:57 GMT

I have created multiple Raid 0+1 configurations using the Element Manager Appliance. The raidset consists of 6 72 GB drives divided into three mirrorsets. The element manager reports the capacity of the array at around 210 GB's, however, when I present the LUN to a server, the server, through disk management (WIN2K) sees the array as around 340 GB's. Anyone seen that before or am I missing something?

Re: Strange Disk Problem

BR680056 — Thu, 19 Dec 2002 08:07:12 GMT

From the capacity that's reported it sounds like the 6 disks are configured in RAID5.

...so I would double-check that configuration.

Another (more farfetched) possibility is if the RAID-set is using virtual sizing and reporting a bigger than actual size. Then one must take care to only partition/format the space that's actually there.

Cheers,
Rune

Re: Strange Disk Problem

Eugeny Brychkov — Thu, 19 Dec 2002 08:34:47 GMT

Rune,
ask I see from Dan's words he has 3 disks in 0/1 stripe by 3 disks, so 210GB is correct for 6*72GB (~420GB).
Do you know if array uses compression? Or virtualization keeping some data in packed state or in another RAID level?
Eugeny

Re: Strange Disk Problem

CA878053 — Thu, 19 Dec 2002 15:17:58 GMT

Thank you both for responding to my question. Yes, I have checked the configuration, it sounds like it is configured as RAID 5, it is not, it is RAID 0+1. I confirmed this through a VT 100 session straight to the controller. Three raidsets make up one stripeset which makes up the array. The element manager reports capacity as 210GB but it is being seen by the hosts as 350GB. This is what has me so confused. The controllers are HSG80's so there is no virtualization. In addition, I am not using compression on the server side for the partitions.

Re: Strange Disk Problem

CA878053 — Fri, 20 Dec 2002 21:12:29 GMT

Just an update. I worked with a HP storageworks engineer and he helped me fix the problem. Basically I had to run the DILX command on all the drives. Once that was done I was able to recreate the 0 + 1 raidsets and when I presented them to the host they showed up correctly.