VA7410 Rebuild Performance

[Jerry Glenn]

I have a VA7410 disk array running RAID1+0 that has 105 73GB disks installed. When a disk fails, which seems to be quiet often, the rebuild takes 16-18 hours. During this time our application's performance is drastically degraded. Auto rebuild is set to true, and the rebuild priority is set to low, but we still take a hard hit on our application performance.

I have 2 questions:
1.) Is there anything else about the array that can be set that will help the application performance?
2.) What are the implications of turning auto rebuild off? I worry about this, because if I did this and waited to say the weekend to do the rebuild and another drive failed in the mean time, I am afraid I could lose data.

I have attached an armdsp -a. Any help/advice will greatly appreciated.

[Jim Viera]

We have two VA74000 disk arrays with 75 73GB disks installed on one array, and 45 on the other. We have turned off auto rebuild over a year ago because performance was horrible during a rebuild. We do all of our rebuilds on the weekend to get through the performance hit.

The only thing that I've found to help is to insure that you have sufficient free space (unallocated) on each redundancy group. I keep at least 20% on each RG free.

As far as protection, we are running in RAID 5DP. RAID 5DP provides higher protection against data loss than traditional RAID 5 since failure of two disks in the same group is tolerated by this RAID level.