On Tuesday 10 February 2004 06:45, Randy Rue wrote:
Users have been complaining for some time now that the box hesitates
in some situations, particularly when using "tab" to autocomplete
commands and/or file names, and when entering any command for the
first time in a while. That is, cd'ing to and ls'ing a directory for
the first time might cause the machine to pause for anywhere from 2 to
10 seconds. Oddly, the second time there's no hesitation. This pause
occurs when executing commands at the shell, when connecting to files
via samba, and when accessing server applications via an X-based
client.
I had a similar problem with a 2650 "hesitating"
and got the clue from a post on the linux-poweredge@dell.com list.
The box was trying to increase throughput by caching disk writes ???
and the hesitation was while it flushed its buffers.
Decreasing the buffer size made the pause acceptably short.
John Goerzen
posted to: linux-poweredge@dell.com
Subject: Weird pauses w/new PE2650
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.
Then he answered his own problem:
John Goerzen
posted to: linux-poweredge@dell.com
Subject: Experiences with Debian on PE2650
I had some trouble at first when I had a minimal install and was
copying over gigabytes of data. Every so often, the system would
appear to hang while it flushed out its buffers. This addition to
/etc/init.d/bootmisc.sh solved that:
echo 40 0 0 0 60 300 60 0 0 > /proc/sys/vm/bdflush
(This was suggested at
http://www-106.ibm.com/developerworks/linux/library/l-fs8/#resources)
The defaults are tuned such that if you have 1.8 GB available for the
cache, it will periodically try to flush out several hundred megabytes
in one fell swoop, resulting in these delays.
It worked for me, hope it helps,
michaelj
--
Michael James michael.james@csiro.au
System Administrator voice: 02 6246 5040
CSIRO Bioinformatics Facility fax: 02 6246 5166