Hey Karsten, Very interesting data. Your test is inherently single-threaded so I'm not surprised that the benefits aren't more impressive -- the flash modules on the F20 card are optimized more for concurrent IOPS than single-threaded latency.
Adam On Mar 30, 2010, at 3:30 AM, Karsten Weiss wrote: > Hi, I did some tests on a Sun Fire x4540 with an external J4500 array > (connected via two > HBA ports). I.e. there are 96 disks in total configured as seven 12-disk > raidz2 vdevs > (plus system, spares, unused disks) providing a ~ 63 TB pool with fletcher4 > checksums. > The system was recently equipped with a Sun Flash Accelerator F20 with 4 FMod > modules to be used as log devices (ZIL). I was using the latest snv_134 > software release. > > Here are some first performance numbers for the extraction of an uncompressed > 50 MB > tarball on a Linux (CentOS 5.4 x86_64) NFS-client which mounted the test > filesystem > (no compression or dedup) via NFSv3 (rsize=wsize=32k,sync,tcp,hard). > > standard ZIL: 7m40s (ZFS default) > 1x SSD ZIL: 4m07s (Flash Accelerator F20) > 2x SSD ZIL: 2m42s (Flash Accelerator F20) > 2x SSD mirrored ZIL: 3m59s (Flash Accelerator F20) > 3x SSD ZIL: 2m47s (Flash Accelerator F20) > 4x SSD ZIL: 2m57s (Flash Accelerator F20) > disabled ZIL: 0m15s > (local extraction 0m0.269s) > > I was not so much interested in the absolute numbers but rather in the > relative > performance differences between the standard ZIL, the SSD ZIL and the disabled > ZIL cases. > > Any opinions on the results? I wish the SSD ZIL performance was closer to the > disabled ZIL case than it is right now. > > ATM I tend to use two F20 FMods for the log and the two other FMods as L2ARC > cache > devices (although the system has lots of system memory i.e. the L2ARC is not > really > necessary). But the speedup of disabling the ZIL altogether is appealing (and > would > probably be acceptable in this environment). > -- > This message posted from opensolaris.org > _______________________________________________ > zfs-discuss mailing list > zfs-discuss@opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss -- Adam Leventhal, Fishworks http://blogs.sun.com/ahl _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
