Hello michael, michael rodriguez: > I netboot debian linux (etch). I mount the OS filesystem over nfs with > aufs. kernel version 2.6.29.6 using the aufs patches. I am seeing > situations where processes pile up on aufs read locks. The problem > occurs on active web servers with io utilization of about 10-20%. The > machine stays responsive and can often recover, but the load spikes into > the hundreds. > > here is a partial kernel stack trace from when the problem is occuring. > Is there an easy way to avoid this bottleneck?
I've checked the stacktraces and translated these addresses into symbols by simple '#define' and cpp(1). It shows that nfs_permission() calls aufs_read_lock(). It is impossible. How did you mount aufs (on nfs client), and how did you mount and export (on nfs server)? The stacktrace might be incorrect which depends upon your kernel configuration. Finally I want you to read the aufs README file, and provide these information. While you wrote your kernel is 2.6.29.6, ksymoops says 2.6.24.4. Which is correct? (from aufs README) ---------------------------------------------------------------------- When you have any problems or strange behaviour in aufs, please let me know with: - /proc/mounts (instead of the output of mount(8)) - /sys/module/aufs/* - /sys/fs/aufs/* (if you have them) - /debug/aufs/* (if you have them) - linux kernel version if your kernel is not plain, for example modified by distributor, the url where i can download its source is necessary too. - aufs version which was printed at loading the module or booting the system, instead of the date you downloaded. - configuration (define/undefine CONFIG_AUFS_xxx) - kernel configuration or /proc/config.gz (if you have it) - behaviour which you think to be incorrect - actual operation, reproducible one is better - mailto: aufs-users at lists.sourceforge.net ---------------------------------------------------------------------- J. R. Okajima ------------------------------------------------------------------------------ Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference
