taob@risc.org (Brian Tao) writes:
How fast can I realistically expect an F740 to write out filesdoing a restore?
[...]
ufsdump 0bf 128 - /dev/rdsk/c1t0d0s0 | rsh home-tape restore xbfD 128 - /vol/vol0/local
The F740 (home-tape) seems to be the bottleneck in this case:# rsh home-tape sysstat 5 CPU NFS CIFS HTTP Net kB/s Disk kB/s Tape kB/s Cache in out read write read write age 100% 0 0 0 6316 104 29 6127 0 0 >60 99% 0 0 0 6396 106 28 6558 0 0 >60 100% 0 0 0 6356 105 24 7764 0 0 >60 100% 0 0 0 6316 104 40 7189 0 0 >60 93% 0 0 0 5983 99 28 6112 0 0 >60 100% 0 0 0 6395 106 28 6465 0 0 >60 99% 0 0 0 6272 104 51 8878 0 0 >60 100% 0 0 0 6506 107 36 6149 0 0 >60 [...]
I've achieved somewhat higher disk write rates than that during a restore on a F740 from a locally attached DLT7000, and the limiting factor then was the tape speed (restore was essentially the same speed as dump, on an otherwise fairly idle system). I didn't keep careful notes, but my recollection is that the F740 CPU utilisation was under 50%. The network driving overheads do seem to be implicated in your case.
BTW, the ufsdump 'b' is in 512-byte blocks while the ONTAP restore 'b' is in kilobytes, so specifying the latter as 128 is unnecessarily large. I doubt whether that's anything to do with the performance problem, though.
Chris Thompson University of Cambridge Computing Service, Email: cet1@ucs.cam.ac.uk New Museums Site, Cambridge CB2 3QG, Phone: +44 1223 334715 United Kingdom.