I have a PowerEdge 2900 III with a PERC 6/i Controller. The PERC has 2 arrays, each one with 3 hard drives and each hard drive is the same size/speed (146GB 15K rpm SAS).
I would like to delete the second array and add those disks to the first, so we have a single 6-disk RAID 5 array. Then I'd like to convert the array to RAID 6.
Is this possible without losing any data on the first array?
Normally you can reconfigure your drives from a RAID5 to a RAID6 on the controller and it will not delete data. Then, you just have to extend the partition on the OS level.
It is still VERY RECOMMENDED to have a backup if something unexpected happen!
When going from RAID5 to RAID6, you will have less space available, as you need two instead of one parity disks, so I don't think that's going to work as you are simply lacking one disk's space to have the same net capacity as with the 6 disk RAID5 array.
Since you would have a slow system anyway during the migration, I would suggest copying the data to one (or better two) larger disks (i.e. 1TB USB), rebuild the array and copy the data back.
Edit: One alternative might be to take one of the disks out of the array you want to keep (this will leave you without redundancy, so be careful), create a 4 disk RAID6, move the data over to the RAID6 and then add the other two disks to it.
