Andi Kleen wrote: >> Theodore Tso <tytso@xxxxxxx> writes: >> > Now, there are good reasons for doing periodic checks every N mounts >> > and after M months. And it has to do with PC class hardware. (Ted's >> > aphorism: "PC class hardware is cr*p"). >> >> If these reasons are good ones (some skepticism here) then the correct >> way to really handle this would be to do regular background scrubbing >> during runtime; ideally with metadata checksums so that you can actually >> detect all corruption. >> >> But since fsck is so slow and disks are so big this whole thing >> is a ticking time bomb now. e.g. it is not uncommon to require tens >> of minutes or even hours of fsck time and some server that reboots >> only every few months will eat that when it happens to reboot. >> This means you get a quite long downtime. > > Has there been some thought about an incremental fsck? While an _incremental_ fsck isn't so easy for existing filesystem types, what is pretty easy to automate is making a read-only snapshot of a filesystem via LVM/DM and then running e2fsck against that. The kernel and filesystem have hooks to flush the changes from cache and make the on-disk state consistent. You can then set the the ext[234] superblock mount count and last check time via tune2fs if all is well, or schedule an outage if there are inconsistencies found. There is a copy of this script at: http://osdir.com/ml/linux.lvm.devel/2003-04/msg00001.html Note that it might need some tweaks to run with DM/LVM2 commands/output, but is mostly what is needed. Cheers, Andreas -- Andreas Dilger Sr. Staff Engineer, Lustre Group Sun Microsystems of Canada, Inc. - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
