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I have 1 cluster with serveral p4500.

There is HW Raid5 and the Raid5 is split on: first 6 is one raid 5, and the other 6 is one raid 5.

There were two disk that came up with a fault.

I replaced both disk in same Raid5.

Now the storagesystem says that Volumes is unaccessable and the Raid5 of the P4500 is down.

How can I get the lefthand up and working again? Ive tried to put the old disk in the P4500 again, but this does not help.

I also tryed to restart the disk shelf as well.

Do you have any idea? Or something to get it to work again?

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It sounds like you may have swapped out the wrong disks - which would kill your arrays - you may need to wipe and restore. –  Chopper3 Jul 7 '12 at 9:15
    
@Chopper3 I read this as him replacing two failed disks in the same R5 set. –  MDMarra Jul 7 '12 at 13:35
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3 Answers

P4500s in RAID 5 actually do a RAID 50 across the 12 physical disks in the shelf. It's a 6 to 6 split that is then striped across. They are not independent RAIDs. This means that if you lost one array, all of the data on that shelf is gone.

The good news is that you say this is a member of a cluster. If it's a mirrored cluster like it should be (Network RAID 1) then popping the new disks in should cause there to be a rebuild from the other nodes in the cluster. If it doesn't happen automatically, consult your manual. I've never has a whole array fail in a P4500. A full rebuild from another node can take a long long time. In the management console, you can adjust the max throughput for this operation. The default setting is 16MBps. Keep in mind that adjusting this can impact production.

If you set this up as Network RAID 0, then all of the data on all cluster nodes is lost. Start pulling your tape backups, you have a lot of work ahead of you.

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I'm not familiar with the HP P4500 but under normal circumstances loosing 2 disks from the same raid 5 array means you'll be reaching for the backups once you've reinitialsed the array.

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I concur with @lain but it seems like @Soeren's English is a bit broken, so I thought he might need it broken down a bit more.

A RAID5 only has one disk fault tolerance, meaning if two disks fail at the same time, your array has become useless and the data has been lost.

I'm not too familiar with the HP P4500, but if you run risk of two drives failing in the future again, before replacing the first, you might want to consider changing to a RAID6.

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