In place upgrade of a software raid 5 array I run a software raid array for my backups, but my data has outgrown capacity. considering I have a full 2.4TB array with 5*600GB drives and also have 5*2TB drives I would like to swap in. What would be the nicest way to upgrade the array? I thought of faulting 1 drive at a time and swapping in a new drive and rebuilding, but I am not sure if at the end of the process I will be able to resize the array Thoughts?

Assuming this is linux, this is doable and pretty easy actually. It is covered on the software raid wiki but the basic steps are:

1. Fail and remove drive.
2. Replace with a larger drive.
3. Partition the drive so the partitions are the same size or larger than the ones in the existing software raid partition.
4. Add the partitions to software RAID and wait for it to sync.
5. Repeat above steps until all drives have been replaced.
6. `mdadm --grow /dev/mdX --size=max` to resize the mdadm device.
7. `resize2fs /dev/mdX` to resize the file system assuming you have ext3.



You can grow the mdadm device and the file system while the server is live too. If your drives are hot swappable you can do everything without downtime.