My home Linux server has a four drive software RAID 5, where each SATA drive has two partitions, named sd[abcd]. /dev/md1 is built up from sd[abcd]1, /dev/md2 is built up from sd[abcd]2. Each drive is 500GB, and each partition is 250GB. I use LVM to merge md1 and md2 into a single volume group.
What would be a good procedure to upgrade these drives to 1TB each? I have no more available SATA ports. I've considered pulling one of the drives out, replacing it with a new 1TB drive partitioned with two 250GB partitions, and a 500GB partition, and rebuilding the array. Repeat for each drive, then create a new RAID5 on sd[abcd]3. That seems "less than optimal": abusing the sync/recovery process seems to not be the right way to do this.
Does it make more sense to use an external USB enclosure, stick in a new 1TB disk, partition it, add it to the md1 and md2 arrays, resync, then remove one of the old disks from the array, repeating that for each disk?
There's really no good reason to have multiple arrays, spread across the same disks, so if the process eliminated that, that would be good.
Thanks for your suggestions!