I have Ubuntu server with 1x2TB HDD and 1x128GB SSD (unused). There are 2 partitions: /boot, and a physical volume for LVM, which has 1 group and 5 logical volumes: /, /var/log, /home, /srv, /tmp.
Recently the 2nd 2TB HDD arrived. We need better redundancy, so I'm looking at either joining 2 HDDs into 1 RAID1 (with /boot, /, and an LVM partition with /home, /var/log, /srv, /tmp), or adding 2nd HDD as LVM physical volume, and using LVM mirroring for logical partitions.
In addition to redundancy, I need to achieve 2 more goals: - relatively safe change from 1xHDD to 2xHDDs (I'm administering remotely a live system) - easy future extensions of LVM partitions.
Here, is RAID1 superior to LVM mirroring? (I believe it is. I'm talking software RAID1 here.)
If it is - what would be the best way to convert a 1xHDD live system to a 1xRAID1 live system remotely, if all I have is an empty 128GB SSD, and all HDD data currently fits onto it easily?