Ray Galvin wrote: > I appear to be seeing the performance of a local ZFS file system degrading > over a short period of time. > > My system configuration: > > 32 bit Athlon 1800+ CPU > 1 Gbyte of RAM >
SInce you only have 1 GByte of RAM, I would suspect the ARC is filling and becoming less useful as it works harder to find space. This processor isn't very fast, so you might notice it on this sort of machine. Get arcstat and use it to track how the ARC is being used for the different runs. http://blogs.sun.com/realneel/entry/zfs_arc_statistics -- richard > Solaris 10 U6 > SunOS filer 5.10 Generic_137138-09 i86pc i386 i86pc > 2x250 GByte Western Digital WD2500JB IDE hard drives > 1 zfs pool (striped with the two drives, 449 GBytes total) > 1 hard drive has an 8 Gbyte UFS slice holding the OS root filesystem > > My test consists of reading a single 2.3 Gbyte file using 'dd'. Immediately > after booting the system, I am seeing a read speed of nearly 100 Mbyte per > sec. This is wonderful and shows that the ZFS striping is giving a > performance boost as the maximum data rate from each drive is much lower than > that - somewhere around 60 Mbytes/sec. Unfortunately if I rerun the test > multiple times, the performance degrades. By the 18th time (about 10 minutes > later) the test is run, the performance is down to 54 Mbyte/sec. It is > interesting to note that the read performance of the UFS root filesystem has > not degraded during the above testing. The large file read performance of > the root UFS filesystem remains constant at 58 Mbytes. > > I'm running a fresh install of sol-10-u6-ga1-x86-dvd.iso. The only > processes running on the system are the standard ones that happen with a > fresh install. > > Does anyone know if this performance degradation is normal? If not, does > anyone have hints on what I should do to track down the problem. > > Thanks. > > Ray > > > ----------The log of my runs is shown below------------ > > # time dd if=big2 of=/dev/null bs=1024k > 2201+1 records in > 2201+1 records out > > real 23.8 > user 0.0 > sys 11.1 > # time dd if=big2 of=/dev/null bs=1024k > 2201+1 records in > 2201+1 records out > > real 24.5 > user 0.0 > sys 8.9 > # time dd if=big2 of=/dev/null bs=1024k > 2201+1 records in > 2201+1 records out > > real 27.4 > user 0.0 > sys 8.8 > # time dd if=big2 of=/dev/null bs=1024k > 2201+1 records in > 2201+1 records out > > real 26.9 > user 0.0 > sys 8.4 > # time dd if=big2 of=/dev/null bs=1024k > 2201+1 records in > 2201+1 records out > > real 32.0 > user 0.0 > sys 8.5 > # time dd if=big2 of=/dev/null bs=1024k > 2201+1 records in > 2201+1 records out > > real 31.4 > user 0.0 > sys 8.6 > # time dd if=big2 of=/dev/null bs=1024k > 2201+1 records in > 2201+1 records out > > real 33.2 > user 0.0 > sys 8.8 > # time dd if=big2 of=/dev/null bs=1024k > 2201+1 records in > 2201+1 records out > > real 34.1 > user 0.0 > sys 8.9 > # time dd if=big2 of=/dev/null bs=1024k > 2201+1 records in > 2201+1 records out > > real 35.9 > user 0.0 > sys 8.9 > # time dd if=big2 of=/dev/null bs=1024k > 2201+1 records in > 2201+1 records out > > real 36.8 > user 0.0 > sys 8.7 > # time dd if=big2 of=/dev/null bs=1024k > 2201+1 records in > 2201+1 records out > > real 38.1 > user 0.0 > sys 8.9 > # time dd if=big2 of=/dev/null bs=1024k > 2201+1 records in > 2201+1 records out > > real 38.4 > user 0.0 > sys 8.9 > # time dd if=big2 of=/dev/null bs=1024k > 2201+1 records in > 2201+1 records out > > real 39.4 > user 0.0 > sys 9.0 > # time dd if=big2 of=/dev/null bs=1024k > 2201+1 records in > 2201+1 records out > > real 40.3 > user 0.0 > sys 8.9 > # time dd if=big2 of=/dev/null bs=1024k > 2201+1 records in > 2201+1 records out > > real 40.6 > user 0.0 > sys 9.0 > # time dd if=big2 of=/dev/null bs=1024k > 2201+1 records in > 2201+1 records out > > real 41.3 > user 0.0 > sys 9.0 > # time dd if=big2 of=/dev/null bs=1024k > 2201+1 records in > 2201+1 records out > > real 42.2 > user 0.0 > sys 9.0 > # time dd if=big2 of=/dev/null bs=1024k > 2201+1 records in > 2201+1 records out > > real 42.4 > user 0.0 > sys 9.2 > # > _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
