On Fri, May 25, 2007 at 09:41:05AM +0200, Claus Guttesen wrote: > >> I have just (re)installed FreeBSD amd64 current with gcc 4.2 with src > >> from May. 21'st on a dual Dell PE 2850. Does the post-gcc-4-2 current > >> include all your zfs-optimizations? > >> > >> I have commented out INVARIANTS, INVARIANTS_SUPPORT, WITNESS and > >> WITNESS_SKIPSPIN in my kernel and recompiled with CPUTYPE=nocona. > >> > >> A default install solaris fares better io-wise compared to a default > >> FreeBSD where writes could pass 100 MB/s (zpool iostat 1) and FreeBSD > >> would write 30-40 MB/s. After adding the following to > >> /boot/loader.conf writes peak at 90-95 MB/s: > >> > >> vm.kmem_size_max=2147483648 > >> vfs.zfs.arc_max=1610612736 > >> > >> Now FreeBSD seems to perfom almost as good as solaris io-wise although > >> I don't have any numbers to justify my statement. I did not import > >> postgresql in solaris as one thing. > >> > >This patch also improve concurrency in VFS: > > > > http://people.freebsd.org/~pjd/patches/vfs_shared.patch > > I applied the patch and it seems to speed up my reads and writes. > Watching zpool iostat I saw reads at 155 MB/s and writes at 111 MB/s. > But it also seems to introduce some minor complete stops accessing the > zpool lasting for 10-20 secs. I apologize I'm not very specific but I > only had time to test disk-io but not digg into the issues. > > >When you want to operate on mmap(2)ed files, you should disable ZIL and > >remote file systems: > > > > # sysctl vfs.zfs.zil_disable=1 > > # zpool export <name> > > # zpool import <name> > > Won't disabling ZIL minimize the chance of a consistent zfs-filesystem > if - for some reason - the server did an unplanned reboot?
ZIL in ZFS is only used to speed-up various workloads, it has nothing to do with file system consistency. ZFS is always consistent on disk no matter if you use ZIL or not. -- Pawel Jakub Dawidek http://www.wheel.pl [EMAIL PROTECTED] http://www.FreeBSD.org FreeBSD committer Am I Evil? Yes, I Am!
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