At what Solaris10 level (patch/update) was the "single-threaded compression" situation resolved? Could you be hitting that one?
-- MikeE -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Roch - PAE Sent: Tuesday, June 26, 2007 12:26 PM To: Roshan Perera Cc: zfs-discuss@opensolaris.org Subject: Re: [zfs-discuss] ZFS - DB2 Performance Possibly the storage is flushing the write caches when it should not. Until we get a fix, cache flushing could be disabled in the storage (ask the vendor for the magic incantation). If that's not forthcoming and if all pools are attached to NVRAM protected devices; then these /etc/system evil tunable might help : In older solaris releases we have set zfs:zil_noflush = 1 On newer releases set zfs:zfs_nocacheflush = 1 If you implement this, Do place a comment that this is a temporary workaround waiting for bug 6462690 to be fixed. About Compression, I don't have the numbers but a reasonable guess would be that it can consumes roughly 1-Ghz of CPU to compress 100MB/sec. This will of course depend on the type of data being compressed. -r Roshan Perera writes: > Hi all, > > I am after some help/feedback to the subject issue explained below. > > We are in the process of migrating a big DB2 database from a > > 6900 24 x 200MHz CPU's with Veritas FS 8TB of storage Solaris 8 to > 25K 12 CPU dual core x 1800Mhz with ZFS 8TB storage SAN storage (compressed & RaidZ) Solaris 10. > > Unfortunately, we are having massive perfomance problems with the new solution. It all points towards IO and ZFS. > > Couple of questions relating to ZFS. > 1. What is the impace on using ZFS compression ? Percentage of system > resources required, how much of a overhead is this as suppose to > non-compression. In our case DB2 do similar amount of read's and > writes. > 2. Unfortunately we are using twice RAID (San level Raid and RaidZ) to > overcome the panic problem my previous blog (for which I had good > response). > 3. Any way of monitoring ZFS performance other than iostat ? > 4. Any help on ZFS tuning in this kind of environment like caching etc ? > > Would appreciate for any feedback/help wher to go next. > If this cannot be resolved we may have to go back to VXFS which would be a shame. > > > Thanks in advance. > > _______________________________________________ > zfs-discuss mailing list > zfs-discuss@opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
