raid 5 to raid 6 migration

[Alexander Ramos]

I have a dl360 g5 with the p400i controller. We just got the battery backed cache upgrade installed. however there was already one array with two raid 5 logical drives configured.

my question is can i migrate both logical drives from raid 5 to raid 6? The server is running centos (red hat clone). When I open the ACU and click the logical drives I am given the option to migrate raid/strip size but the fault tolerance options are either Raid 5 (current) or raid 0.

Do I need something else besides the battery backed cache (512mb)?

Or am I stuck rebuilding? Thanks for your time.

All drives bays are filled with 72gb sas drives if that matters.

[BenS · Accepted solution]

It sounds like you may be stuck with rebiulding with that configuration. RAID 6 arrays give you n-2 drives available for data (as opposed to n-1 for RAID 5). If you had spare bays available, you may have been able to add another hard drive, and with that migrate to a RAID 6 array, but since all drive bays are populated, you're probably out of luck.

[TTr]

When you convert from R5 to R6 you are assigning another hard disk as parity so you are losing that same space from the total effective space of the R5 group. Do you have the equivalent of 1 hard disk unallocated in the existing r5 group? If so you may be able to do it. That is after you add the BBWC. Otherwise if your LUNs are using up most of the R5 space you can't do it.

[Patrick Terlisten]

Hello,

you need enough free space for the new, additional parity informations. So add new disks or release spare drives and add them to the array.

Best regards,
Patrick

[Alexander Ramos]

Thanks. Not the answers I wanted to hear but the correct ones.