Quoting sf...@users.sourceforge.net: > dan...@zoltak.com: >> > How much RAM does your system have? >> >> 16GB and 8 cores. > > Memory large enough. > CPU many enough. > Let's keep in mind about lock contension. > > Just to make sure, you can see them all via /proc. Right? >
Everything is showing up as expected. > > >> Something that I have noticed. >> >> On the AUFS system if I do: >> # ps -ef |grep flush >> root 2893 2 0 Jan24 ? 00:00:00 [kdmflush] >> root 2902 2 0 Jan24 ? 00:00:00 [kdmflush] >> root 4639 2 0 Jan24 ? 00:00:04 [flush-253:0] >> >> lsof -p 4639 >> COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME >> flush-253 4639 root cwd DIR 0,17 260 2 / >> flush-253 4639 root rtd DIR 0,17 260 2 / >> flush-253 4639 root txt unknown /proc/4639/exe >> >> >> On the non-AUFS system if I do the same: >> # ps -ef |grep [f]lush >> root 319 2 0 Jan25 ? 00:00:00 [pdflush] >> root 320 2 0 Jan25 ? 00:00:00 [pdflush] >> root 2042 2 0 Jan25 ? 00:00:00 [kdmflush] >> root 2052 2 0 Jan25 ? 00:00:00 [kdmflush] >> >> I'm not sure if this has any relevance? > > - there is no pdflush on aufs system. > generally it should exist on aufs system too. please check your > system again. > > - flush-xx:xx exists on aufs system only. > it is a kernel thread for a block device. > as long as your kernel is unchanged, it should exist on non-aufs > system too. > as you might know, aufs doesn't have its backend block device. so > generally speaking, such kthread is unrelated to aufs. > > If local block device is related to your load average, you may find > something by iostat(8) or something. > > >> There is no doubt something odd is happening. The performance >> difference has to lie with the AUFS kernel module somewhere? > > I don't know why you call your load average as "performance". > If you want to know how the performance of your apache server is > changed, I'd suggest you to try benchmarking from http client. Yes my mistake. The latency has gone up a bit but not by much. > If you want to know about the caching in NFS client, I'd suggest you to > try "time find /home -xdev -ls > /dev/null" or something. The NFS cache is working as expected. I've performed more tests and have found that there is something going on with NFS unrelated to AUFS as I have now managed to verify that AUFS is not causing the performance issue. Thanks again for helping with diagnosing the issue. Your insight is appreciated greatly. Thanks, Dan Z. ------------------------------------------------------------------------------ Special Offer-- Download ArcSight Logger for FREE (a $49 USD value)! Finally, a world-class log management solution at an even better price-free! Download using promo code Free_Logger_4_Dev2Dev. Offer expires February 28th, so secure your free ArcSight Logger TODAY! http://p.sf.net/sfu/arcsight-sfd2d
