Andre Noll wrote:
On 13:33, Chris Snook wrote:
During the daily cron job that uses rsync to sync a 500G file system
>from another machine to the raid on the 3ware controller the load
jumps up, and the machine becomes sluggish as hell. For example, an
ssh login to that machine takes minutes to complete and ldap becomes
unreliable while the rsync job is running. Even Nagios complains
about the machine being down while rsync is running.
You're putting your box under astronomical load. This is generally
regarded as a bad idea, regardless of how well your storage controller
is performing.
The machine becomes sluggish also when I write directly to the raid
array. A simple
dd if=/dev/zero of=tmpfile
shouldn't push the load up to 4, right?
Actually, it's normal for pdflush to spawn up to 8 threads when you're
dirtying memory faster than it can be written to disk. Load going to 4
is not abnormal. ssh logins taking minutes is very abnormal.
Can you measure the single-threaded throughput (say,
coping one huge file, and then syncing) to give us a baseline
performance figure?
Single threaded throughput seems to be ok (140M/s). The problem is
that the machine becomes unresponsive.
Does the machine become unresponsive during the single-threaded test, or
only when doing the rsync?
-- Chris
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