On 09/29/2009 07:14 PM, [email protected] wrote:
Hi

I've been noticing some long delays on doing a simple `ls' in
directories that haven't been recently accessed on a test glusterfs
system we've put together.  The system(s) consists of a 4 node
DHT + AFR (x1) setup, running 2.0.6 all with 10GbE connectivity
between the nodes (and no there is no network bottleneck here as
iperf proves that the throughput between the machines is ~9Gbps).


I would suggest following advice in another thread:

  
http://www.gluster.com/community/documentation/index.php/Translators/cluster/distribute
>
>  It seems to suggest that 'lookup-unhashed' says that the default is 'on'.
>
>  Perhaps try turning it 'off'?
Wei,
    There are two things we would like you to try. First is what Mark
has just pointed, the 'option lookup-unhashed off' in distribute. The
second is 'option transport.socket.nodelay on' in each of your
protocol/client_and_  protocol/server volumes. Do let us know what
influence these changes have on your performance.

Avati

The TCP_NODELAY seems particularly relevant to me if many small requests are being issued in sequence as a /bin/ls is likely to do?

The lookup-unhashed might be relevant to stat() calls issued as a part of the /bin/ls process.

I've been hitting 'ls' problems myself on another system with NFS and AutoFS where we have a directory with many symlinks in it. The 'ls' does a stat() on each of the symlinks, and in the case of auto-mount - it can take a while... :-)

There is a stat-prefetch module that I do not see documentation for. I wish there was more comments. A quick skim of it suggests that it *might* be designed to improve /bin/ls performance. That it's not documented may mean it is for 2.1 or later?

Cheers,
mark


--

Mark Mielke<[email protected]>

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