Re: [BUG] RAID sub system

From: Roy Sigurd Karlsbakk (roy@karlsbakk.net)
Date: Sat Dec 15 2001 - 13:16:41 EST

> sysrq-t output from a "hung" system would give some valuable info as to
> why it's stuck.

It never hangs. It just slows down the i/o to ~ 1MB/s

also ... I started out with 200 'dd' processes (as the script I sent
earlier). The i/o gets stuck, and ... strange ...

# killall dd

watching vmstat

   procs memory swap io system cpu
 r b w swpd free buff cache si so bi bo in cs us sy id
 0 200 0 0 3280 4092 782072 0 0 1054 0 621 657 0 4 96
 0 200 0 0 3284 4092 782108 0 0 1042 0 631 665 1 1 98
 0 101 0 0 3672 4164 804600 0 0 17594 0 762 931 2 9 88
 0 56 1 0 3248 4180 815332 0 0 32598 0 897 727 0 10 90
 0 30 1 0 3276 4212 821640 0 0 33102 40 910 447 1 6 92
 0 1 1 0 3252 4236 829080 0 0 31692 0 947 301 1 9 90
 0 0 0 0 3296 4236 829320 0 0 2042 0 401 132 0 0 100
 0 0 0 0 3288 4244 829320 0 0 0 26 360 132 0 0 100
 0 0 0 0 3288 4244 829320 0 0 0 0 326 127 0 0 100
 0 0 0 0 3288 4244 829320 0 0 0 0 358 127 0 0 100

It speeds up again when the processes start to die, although the number of
processes started has no effect of the outcome. After a while the i/o
stops completely up (see above lines 1,2).

I also noted a quite a dramatic speed reduction in 2.4.17-rc1 compared to
2.4.16. 2.4.16 gave me up to 50 megs / sec, wheras 2.4.17-rc1 only gives
me around 35.

roy 

--
Roy Sigurd Karlsbakk, MCSE, MCNE, CLS, LCA

Computers are like air conditioners.
They stop working when you open Windows.

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This archive was generated by hypermail 2b29 : Sat Dec 15 2001 - 21:00:30 EST