Reminder -- RAID 5 is not your friend

[Richard Pieri]

On Mar 11, 2010, at 1:20 PM, Derek Martin wrote:
> 
> The odds are much, much lower than that, though you need to figure in
> MTBF and the time period over which you're concerned.  If your time
> period is long enough, you have a 100% chance of losing your data.
> Only not really... because you're a good sysadmin, and you do regular
> back-ups, keep your important data in replicated revision control
> systems, etc.

True.  I should have written something like: I don't consider a 1 in 2 chance of data lost *in the event of a second failure* to be "reliable" beyond the basic no single point of failure.

Ultimately, though, the point I'm trying to make is that switching from RAID 5 to RAID 10 is not a useful improvement in reliability.  Yes for performance, but if you want to improve reliability you need to invest a lot more in disks and nested RAID and possibly storage replication.

--Rich P.