David Brown wrote: > On Wed, Aug 20, 2008 at 01:13:50PM -0700, James G. Sack (jim) wrote: > >> So I wonder which (controllers &) drives support write barriers. How >> does one find out? The hdparm help and manpage seem silent about it. I >> suppose there might be some parm in /sys/block/sda (or?), but I can't >> see anything obviously relevant. > > If you have a partition to spare, you can make an XFS partition on it, > and try mounting it. XFS complains loudly if it doesn't have barrier > support. > > This is most notable because barriers don't seem to yet make it > through LVM. > > Supposedly, XFS is a lot more robust with barriers, and there isn't > all that significant of a performance change. It might be because it > was designed with them in mind, instead of kind of using them as a > slightly better alternative to writing everything synchronously. >
ZFS was also mentioned earlier in this thread. What is the right question to ask? Is ZFS inherently immune to these (sudden power loss?) problems? Is write barrier strategy an unnecessary kludge in ZFS architecture? (or what?) A different question: Does anyone know what really happens internally when a disk loses power? Regards, ..jim -- [email protected] http://www.kernel-panic.org/cgi-bin/mailman/listinfo/kplug-list
