[mythtv-users] Why RAID 5 stops working in 2009

[David Brodbeck]

Thomas Fjellstrom wrote:
> On Thursday 23 October 2008, John Drescher wrote:
>> Also even in this unlikely case with mdadm you should be able to copy
>> the bad drives to new drives and force the arrays to sync even with
>> the missing data. I am not sure if hardware controllers allow you to
>> sync disks that have problems like this.
> 
> If that sector is a parity sector, and its lost its original data, a restore 
> is going to destroy a lot of data from what I've heard.

You'll lose one stripe of data.  Or more accurately, one stripe will be
silently corrupted.  Whether this is a big deal or not depends on where
that stripe is.  If it's in the middle of an MPEG video file it's
probably no big deal.  If it's a database table, or a subdirectory, you
better have a backup.