After the near-miss with my little black fileserver at home (one drive had a hiccup; my girlfriend recovered it) I've been reading up on various file-storage information: RAID, LVM (volume management) and filesystems. Unfortunately, what I'm reading is making me paranoid to the extreme!

For one thing, I know the setup I have at the moment is fragile at best: I have two 500GB drives in a single volume-group, with about 750GB data on them. The problem is, as I now realise, if I lose either drive the entire volume-group is hosed. Worse, I don't have backups (well, I do have the original DVDs that the movies are on, but it would be a right pain to have to re-rip them all).

So I started researching. What about RAID, I thought, and quickly decided that mirroring (RAID-1) is a waste of diskspace. RAID-5 looks better, but can only survive a single disk failure at a time, so perhaps RAID-6 with a total of 5 drives? That would give the capacity of 3 full drives and the ability to recover if any two drives died on me.

On top of that I could put a volume-group. If I'm reading things correctly, this would mean I could a) add a new HDD (of any size?) first to the RAID array, then the volume-group, and be able to use the new space ... possibly without restarting, since SATA is (mostly) hot-swappable. That's what I want, of course -- the ability to start with (minimum) 4 drives, but upgrade (and move to bigger drives) in the future.

To add to this mix, a guy at work (we'll call him Greeny) started "wibbling" about ZFS on (Open)Solaris (and FreeBSD, it turns out). End-to-end data-integrity, it says. Avoid silent data-corruption, it says. Suddenly I'm obsessed -- are my hard-drives randomly swapping bits here and there? Slowly (but surely) corrupting the files?

Yep, they sure are. ZFS promises to stop this by introducing a checksum process (which will notice such bit-swapping and - also silently - fix the file back to a "good" state from one of it's copies). So ZFS and RAID-Z are good things and I want them. But...

... it's not quite there on Linux. Someone has implemented it with FUSE (filesystem in user-space), but it's certainly not considered "stable". Even on FreeBSD it's "development". So the question is: do I go with the trusted, well-known and well-supported (hardware-wise) Linux, or it's once-commercial brother OpenSolaris? If Linux, do I make a ZFS2/RAID-Z filesystem and access it through FUSE?

In either case I better sort out my backups.