On Mon, Jul 14, 2014 at 12:37:09PM +0200, Manuel Bouyer wrote: > On Mon, Jul 14, 2014 at 02:38:14AM +0400, Dima Veselov wrote: > > Hello! > > > > Can someone tell - is there a way to inspect poor hard drive performance? > > > > Two computers - windows and linux, SMB and NFS connected to NetBSD host. > > > > Writing over SMB (GE interface) freeze linux NFS client (writing few bytes > > can take 2 seconds). > > > > I believe thats hard drive problem because iostat show not more than 10MB/s > > even copying locally on NetBSD from one drive to another. Top show up to > > 10% interrupt.
By 'hard disk problem' I had in mind 'not network'. dd benchmarking prove that. > I would try some benchmark like iozone. Don't know if I interpret iozone data correctly, but there is a significant loose of writing speed at 32k (and bigger) blocks, comparing to 16k or smaller. It is seen on write, rewrite, fwrite, frewrite columns. I'm in doubt, because i don't beleive in 800Mb/s or 1Gb/s speed of fwrite (for less than 16k), however 17-20 Mb/s (for 32kb and more) look quite real. The original question was about - how to know where speed loses? > A simple dd from /dev/zero can also give some information: > dd if=/dev/zero of=file bs=1m count=50000 > (you have to make sure the file created doesn't fit in ram). Stats are awful. Linux/amd64 on usual workstation computer gave 111Mb/s NetBSD 6.0/amd64 (with RAIDframe) Intel 82801JI SATA Controller Intel Xeon E5506 working good as server 54.5 Mb/s NetBSD 6.1.4/amd64 which was originally discussed RAIDframe dk-raid-dk sandwitch AMD Athlon(tm) 7750 Dual-Core Processor NVIDIA nForce MCP77 ATA133 IDE Controller gave 13Mb/s > Also you don't say what kind of access you're doing: a single large > file write, or lots of small files ? Don't see much difference. I would say big files make it freeze more, but maybe it just because of little breathes between small ones? :) Iozone don't load much - it take 2-10% CPU and not more than 1% interrupt, but samba bigfile copy take 6% CPU and up to 10% int. Anyway saving this message during iozone make me feel the problem (1-2 seconds of freeze while saving). One more thing - this system previously worked with NetBSD 5 for years and I never noticed anything like that. Hardware was the same except it was 1x1Tb Raidframe disk instead of 2x3Tb now. -- Sincerelly yours
