On Sun 2009-01-04 13:38:34, Theodore Tso wrote: > On Sun, Jan 04, 2009 at 06:35:41PM +0500, Alexander E. Patrakov wrote: > > > > Ext3 means either hardware that supports barriers (not sure how to > > check > > Pretty much all modern disk drives supports barriers. And note that > w/o barriers ext3 has worked pretty well. *If* you have a workload > pushes your system into a mode which where it is very low on memory, > so it is constantly paging/thrashing and you have a workload which is > metadata intensive, and you crash the machine while it is thrashing, > it is possible to end up in a situation where your filesystem is > corrupted and you have to use e2fsck to correct the filesystem. In Are you sure you need to have thrashing? AFAICT metadata + fsync heavy workload should be enough... and there were scripts to easily repeat that. > > Does this requirement apply to other > > journaling filesystems? Do I need journaling at all, given that I have > > an UPS on my desktop and a battery in the laptop? > > Which requirement? Barriers? Most journaling filesystems simply > enable barriers by default. > > And journalling is useful so that if your system crashes, say due to > suspend and resume not working out, or the battery runs dry without > your noticing it, you can avoid running fsck at boot time. It's > really more about shorting the boot time after a crash more than > anything else. Actually, journalling with barriers=0 should still be "safe" in case of kernel crashes (*), right? Because if just kernel is dead, disk firmware will still write the cache back, AFAICT. Pavel (*) kernel crashes that do not involve writing random garbage to disk. -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
