[BUG?] RAID sub system / tux

From: Roy Sigurd Karlsbakk (roy@karlsbakk.net)
Date: Thu Dec 13 2001 - 09:47:07 EST

hi all

After testing this for a while, I'm quite sure there's some kind of bug
that locks up I/O under heavy traffic.

Hardware configuration:

1xAthlon 1133
1GB RAM
1 20G boot disk
2 120G ide drives on a promise ata133 (20269) controller

Kernel: Vanilla 2.4.16 + tux-D0

/etc/raidtab:

raiddev /dev/md0
        raid-level 0
        nr-raid-disks 2
        persistent-superblock 0
        chunk-size 4096

        device /dev/hde
        raid-disk 0
        device /dev/hdg
        raid-disk 1

IDE readahead setting:

echo file_readahead:1024 > /proc/ide/hd[eg]/settings
(I've tried down to 256 with no change.)

file system: independant. I've tried with xfs and ext2 and get the same
result.

Testing:
I make some 100 files, each ~1GB, and start ~100 wget processes to
retrieve data from http://localhost/file-nnnn. Each process is retrieving
a separate file, as to simulate the app. Usually, this works fine in the
beginning, but after a while it all locks up, and the [TUX worker]
(mother) process stops giving me any data, and starts using 100% system
time. If I restart tux, I can do some data retrieval for some time, but
then it locks up again. It's easily reproducable to just start, say, 50
wget processes, killall wget, and then restart the 50 wget processes.

Thanks for all help

regards

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 - 21:00:26 EST