Phil Carns wrote:
claude pignol wrote:
Greetings,
Thanks for your previous answers on the compatibility 2.7.1/ 2.8.1
I have a strange problem:
Version 2.7.1
I/O server AMD Opteron 2350 kernel 2.6.18-164.el5
Client AMD Opteron 2350 kernel 2.6.18-164.el5
In this configuration cp a file from pvfs (using the kernel
interface) is running at 40MB/s
If the client is an Intel Xeon 5550 and the kernel 2.6.18-164.el5
the cp is running at 9 MB/s
and it could go as low as 1.9MB/s with block size of 32KB (dd
if=testfile of=/dev/null bs=32K count=2000)
I did a test with an older kernel 2.6.18-128.el5 on the Intel Xeon
5550 an I get a transfer speed of 40MB/s even with 32K block.
So something has changed in the 164 version. I tested also the
version 2.6.18-164.6.1 and get the same low speed.
Is this a known problem?
Claude
Hi Claude,
What kind of network card does the machine have? Have you tried any
network benchmarks (netpipe or similar) to see if there is network
performance is different in general between the two versions?
-Phil
Hi Phil,
The network chip on the motherboard is an Intel Corporation 82576
Gigabit Network Connection
and It works OK. The problem is the same on all the nodes of a cluster.
Something has changed in the 2.6.18-164.el5 kernel compare to .6.18-128.el5
client machine Intel Xeon 5550 with 2.6.18-164.el5
Read from pvfs (interface kernel using dd)
block 32K 1.6MB/s
block 64K 18.0 MB/s
block 128K 62.5 MB/s
The same machine with 2.6.128.el5
Read from pvfs (interface kernel using dd)
block 32K 41MB/s
block 64K 62.1MB/s
block 128K 61MB/s
Claude
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