Weird pauses w/new PE2650

John Goerzen jgoerzen at complete.org
Mon Jan 27 17:51:01 CST 2003


Hello,

Our new PowerEdge 2650 arrived today. It has the aacraid card with 5
drives, giving us a total of somewhere around 130GB of storage.

I successfully installed Debian 3.0 on it using the standard 2.4.18
boot disk.  I then upgraded to a stock SMP-aware 2.4.20 kernel that I built
myself.  I'm using the tg3 and aacraid drivers for the built-in
hardware, and the aic7xxx driver for the add-on SCSI card Dell gave us
for our external DLT drive.  I partitioned it into two ext3
partitions: one that's 1GB and another that's 128GB (there's another
1GB swap partition).

So, I have a very basic installation -- no daemons, nothing.  I'm
starting to copy over files.  To do that, I'm using netcat piped to
tar on the new PE2650, untarring about 10GB worth of stuff onto the
big partition.

Things start out fine, but then after a few minutes, I notice that
things start pausing.  Everything seems to hang for about x seconds,
where 5 <= x <= 90.  I can type new commands on the shell and hit
Enter, but they don't start up until the x seconds have elapsed.  This
happens every few minutes.  One time, I started up top right after it
happened, and it showed a load average of 6.50 but CPUs 99% idle.  The
hard disk LEDs are flashing during these pauses.

On a lark, I changed the ext3 mount options to data=writeback.  This
seemed to reduce the amount of time it spent "paused", but not the
frequency.  dmesg showed nothing of interest.

Another strange behavior: when I'd un-tar directly from a pipe, like:

nc -l -p 10101 | tar -xvSpf -

then tar would not create symlinks properly, but instead create 0-byte
files with mode 0000 in their place.  But if I'd do:

nc -l -p 10101 > /tmp/foo.tar
tar -xvSpf /tmp/foo.tar

then it would work fine.  Very strange behavior -- I've never seen it
anywhere else, but it is 100% reproducible here.

Any hints?  Thoughts?  Suggestions?

Thanks,
John Goerzen




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