Details
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Bug
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Resolution: Unresolved
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Major
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None
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Lustre 2.1.3
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None
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2.1.3 server with 2.1.3 and 1.8.8 clients. centos6, x86_64, QDR IB
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3
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4173
Description
I've been doing some 2.1.3 pre-rollout testing, and there seems to be a client problem with small random reads. performance is considerably worse on 2.1.3 clients than 1.8.8 clients. it's about a 35x slowdown for 4k random read i/o.
tests use the same files on a rhel6 x86_64 2.1.3 server (stock 2.1.3 rpm is used), QDR IB fabric, single disk or md8+2 lun for an OST, all client & server VFS caches dropped between trials.
checksums on or off and client rpc's 8 or 32 makes little difference. I've also tried umount'ing the fs from the 1.8.8 client between tests to make sure there's no hidden caching, but that didn't change anything.
random read ->
IOR -a POSIX -C -r -F -k -e -t $i -z -b 1024m -o /mnt/yo96/rjh/blah
| i/o size | client version | single disk lun | md8+2 lun |
|---|---|---|---|
| i=4k | 1.8.8 | 20.70 MB/s | 22.0 MB/s |
| i=4k | 2.1.3 | 0.55 MB/s | 0.6 MB/s |
| i/o size | client version | single disk lun | md8+2 lun |
| i=1M | 1.8.8 | 87 MB/s | 137 MB/s |
| i=1M | 2.1.3 | 63 MB/s | 83 MB/s |
although these numbers are for a single process, the same trend applies when the IOR is scaled up to 8 processes/node and to multiple nodes.
