Hi,
On Wed, 12 Jan 2000 22:09:35 +0100, Benno Senoner <[EMAIL PROTECTED]>
said:
> Sorry for my ignorance I got a little confused by this post:
> Ingo said we are 100% journal-safe, you said the contrary,
Raid resync is safe in the presence of journaling. Journaling is not
safe in the presence of raid resync.
> can you or Ingo please explain us in which situation (power-loss)
> running linux-raid+ journaled FS we risk a corrupted filesystem ?
Please read my previous reply on the subject (the one that started off
with "I'm tired of answering the same question a million times so here's
a definitive answer"). Basically, there will always be a small risk of
data loss if power-down is accompanied by loss of a disk (it's a
double-failure); and the current implementation of raid resync means
that journaling will be broken by the raid1 or raid5 resync code after a
reboot on a journaled filesystem (ext3 is likely to panic, reiserfs will
not but will still get its IO ordering requirements messed up by the
resync).
> After the reboot if all disk remain intact physically, will we only
> lose the data that was being written, or is there a possibility to end
> up in a corrupted filesystem which could more damages in future ?
In the power+disk failure case, there is a very narrow window in which
parity may be incorrect, so loss of the disk may result in inability to
correctly restore the lost data. This may affect data which was not
being written at the time of the crash. Only raid 5 is affected.
--Stephen
