Date: Fri, 1 Jun 2007 18:10:53 +0800 From: hshh <hunreal@gmail.com> To: freebsd-performance@freebsd.org Subject: Bad performance while transfer large block size through NFS. Message-ID: <9b6b59500706010310h145a1804ie97e57aa0c5e90a4@mail.gmail.com>
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I set up one NFS server, and mounted on other server by TCP. Servers connected with Giga network, and running 6.2-RELEASE. But I found the performance is very bad while transfering large block size data. For example, I use dd on NFS client to test the speed. # dd if=/dev/zero of=/mnt/test bs=16k count=20k 20480+0 records in 20480+0 records out 335544320 bytes transferred in 6.172289 secs (54363027 bytes/sec) # dd if=/dev/zero of=/mnt/test bs=32k count=10k 10240+0 records in 10240+0 records out 335544320 bytes transferred in 6.481602 secs (51768733 bytes/sec) # dd if=/dev/zero of=/mnt/test bs=512k count=1k 1024+0 records in 1024+0 records out 536870912 bytes transferred in 11.859133 secs (45270671 bytes/sec) # dd if=/dev/zero of=/mnt/test bs=1m count=512 512+0 records in 512+0 records out 536870912 bytes transferred in 11.963019 secs (44877544 bytes/sec) # dd if=/dev/zero of=/mnt/test bs=1651k count=200 200+0 records in 200+0 records out 338124800 bytes transferred in 7.431332 secs (45499891 bytes/sec) # dd if=/dev/zero of=/mnt/test bs=1652k count=50 50+0 records in 50+0 records out 84582400 bytes transferred in 22.319528 secs (3789614 bytes/sec) ----Test End--- As test result, while block size smaller than 1652k, it's fast. But speed drop to only 3.6M/s while block size bigger or equal 1652k. And ``systat -vm 1'' is displayed HDD is most busy, Disks da0 KB/t 16.00 tps 239 MB/s 3.73 % busy 91 Can I do some tuning to improve large block size transfer over NFS?
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