[Openstack] [SWIFT] PUTs and GETs getting slower

Robert van Leeuwen Robert.vanLeeuwen at spilgames.com
Thu Aug 29 08:26:10 UTC 2013

> Hello Robert,
> very interesting experiences and thank you very much sharing them to us.
Thx, good to hear the work is appreciated :)

>Based on your experiences I made some tests with a 256 Byte inode size. I use Ubuntu with kernel 3.5.0 and its working > properly.
> That should reduce the memory consumption and will perform better if I store much more objects.
Yes, in theory that could save 75% of memory although the extra attribute information has to be stored somewhere so I wonder what the net result will be.
We will probably have to wait for Red Hat 7 to get this into our setup unless Red Hat decides to backport it :)

> Deleting objects is a very strange behavior. We delete about 700.000 objects in the night  and the load is rising 50 percent:
We do not delete any objects so I cannot really tell and the benchmark machines I nuked last week.
I would plot the xfs statistics as described in my blogpost to see if the load comes from there.
Running a "iostat -x 10" when you have a high usually also provides a lot of usefull information

I also see you have a quite high network usage. 
We just have about 7MB of traffic which is caused by the rsyncs from the replicators.
With our nodes being quite slow due to the number of files the traffic it is probably a lot less then you are seeing.

Robert van Leeuwen

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