[Openstack] Swift slow write performance
rustam at code.az
Fri Dec 16 03:20:14 UTC 2011
I'm testing swift 1.4.4 setup with 4 nodes/zones on RHEL 5.7. I ran into
the problem of slow writes. Using swift-bench we generated load, writing
hundreds of 4K files. Results:
- Writes - ~3 PUTs/sec (very slow)
- Reads - ~25 GETs/sec (ok)
It's clear that writes are not limited by I/O. To prove that, I
increased file size to 8K, 32K and 64K. In all cases, even with 64K, I
had same result - 3 PUTs/sec.
In the logs of the object servers I can see that each PUT operation
actually took around 0.3 sec which is inline with 3 PUTs/ sec reported
Is that expected performance for such small cluster? Can I break down
those 0.3 seconds spent for PUT operation to see where's bottleneck?
Any advice for troubleshooting this is welcome.
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