I am having a problem with ufs write performance on one of my
partitions on a file server. AdvFS is out of the questions since
this machine is an AFS server.
I am running Digital UNIX version 3.2a. Here is the version info from motd:
DEC OSF/1 V3.2 (Rev. 214); Wed Mar 20 15:58:07 CST 1996
DEC OSF/1 V3.2 Worksystem Software (Rev. 214)
Here are two sample file systems on the server:
Filesystem 1024-blocks Used Avail Capacity Iused Ifree %Iused Mounted on
/dev/rz18c 3381678 2826390 217120 93% 184426 634068 23% /vicepk
/dev/rz20c 3381678 140340 2903170 5% 360 818134 0% /vicepm
If I take a tar file containing about 100 files (total size 500K) and
extract it on /vicepm (the 5% full partition), the extract takes about
3-4 seconds.
If I take that same tar file and extract on /vicepk (the 93% full partition),
the extract takes over 3 minutes. During this time the syd utility reports
that the CPU is 100% occupied (80% kernel, 20% user) and there is 80 disk
accesses per second.
What has caused the performance problem? How can I avoid it?
Is there bug fix for this?
I realize that I should report this through normal software channels,
but the person that does this at the campus computer center is gone
for awhile.
I ran this tar on each file system and here are the results:
/vicepa: 0.070u 0.308s 0:04.60 8.0% 0+1k 120+251io 6pf+0w
/vicepi: 0.075u 0.283s 0:04.48 7.8% 0+1k 29+252io 0pf+0w
/vicepj: 0.070u 0.256s 0:03.39 9.4% 0+1k 15+246io 0pf+0w
/vicepk: 0.082u 3.195s 3:14.25 1.6% 0+2k 13569+274io 6pf+0w
/vicepl: 0.068u 0.292s 0:03.73 9.3% 0+1k 90+252io 5pf+0w
/vicepm: 0.076u 0.257s 0:02.54 12.5% 0+2k 14+244io 0pf+0w
/vicepn: 0.062u 0.276s 0:03.09 10.6% 0+1k 15+247io 0pf+0w
/vicepo: 0.063u 0.304s 0:03.43 10.4% 0+1k 27+249io 0pf+0w
/vicepp: 0.079u 0.353s 0:03.64 11.5% 0+1k 23+320io 0pf+0w
/vicepq: 0.086u 2.893s 2:53.67 1.7% 0+2k 11971+281io 6pf+0w
/vicepr: 0.063u 0.274s 0:03.09 10.6% 0+1k 73+248io 6pf+0w
/viceps: 0.067u 0.271s 0:03.16 10.4% 0+2k 27+253io 0pf+0w
/vicept: 0.067u 0.283s 0:03.91 8.6% 0+2k 41+258io 0pf+0w
/vicepu: 0.070u 0.273s 0:02.79 12.1% 0+1k 15+244io 0pf+0w
/vicepv: 0.067u 0.284s 0:03.32 10.2% 0+2k 16+244io 0pf+0w
Filesystem 1024-blocks Used Avail Capacity Iused Ifree %Iused Mounted on
/dev/rz0c 2032643 574348 1255030 31% 6886 489432 1% /vicepa
/dev/rz16c 3381678 2872786 170724 94% 334765 483729 41% /vicepi
/dev/rz17c 3381678 2135612 907898 70% 143740 674754 18% /vicepj
/dev/rz18c 3381678 2826390 217120 93% 184426 634068 23% /vicepk
/dev/rz19c 3381678 1320189 1723321 43% 52678 765816 6% /vicepl
/dev/rz20c 3381678 140807 2902703 5% 466 818028 0% /vicepm
/dev/rz21c 3381678 2153289 890221 71% 88927 729567 11% /vicepn
/dev/rz22c 3381678 2197772 845738 72% 23874 794620 3% /vicepo
/dev/rz24c 3381678 2165677 877833 71% 105189 713305 13% /vicepp
/dev/rz25c 3381678 2866255 177255 94% 224363 594131 27% /vicepq
/dev/rz26c 3381678 2220525 822985 73% 87068 731426 11% /vicepr
/dev/rz27c 3381678 2734854 308656 90% 175937 642557 21% /viceps
/dev/rz28c 3381678 2875370 168140 94% 97140 721354 12% /vicept
/dev/rz29c 3788144 1160541 2248788 34% 35581 886017 4% /vicepu
/dev/rz30c 3788144 1427794 1981535 42% 106415 815183 12% /vicepv
Thanks in advance for any advice, ...Tim
Tim Theisen Associate Researcher
Internet: tim_at_cs.wisc.edu Department of Computer Sciences
UUCP: uwvax!tim University of Wisconsin-Madison
Phone: (608)262-0438 1210 West Dayton Street
FAX: (608)262-9777 Madison, WI 53706-1685
Received on Wed May 29 1996 - 18:41:30 NZST