Hi Okajima, This is a tough one to reproduce.
I tried: mount -t aufs -o dirs=/var/core:/var/log=ro none /tmp/aufs touch /tmp/aufs/xy and ran these side by side: for ((i=0;i<500000;i++)); do stat /tmp/aufs/xy > /dev/null; done for ((i=0;i<500000;i++)); do touch /var/core/x1;mv /var/core/x1 /var/core/xy; done No luck till now. thanks Prasad ________________________________ From: "sf...@users.sourceforge.net" <sf...@users.sourceforge.net> To: Prasad Koya <kdp...@yahoo.com> Cc: "aufs-users@lists.sourceforge.net" <aufs-users@lists.sourceforge.net> Sent: Wednesday, October 17, 2012 3:18 AM Subject: Re: aufs Warning: Un-notified UDBA Prasad Koya: >Didn't know that this mail is mixing up mime and text. Sorry about that. >Converted to plain text. Hopefully it should be good now. It is plain text only, but still MIME encoded. > Is there a way I could measure the performance impact of enabling > CONFIG_AUFS_HNOTIFY and CONFIG_AUFS_HFSNOTIFY. aufs manual says "udba=notify" > could have significant performance impact. Significant? I don't mean it will be huge regression. udba=notify will surely consume more resources, but I don't know how much. It is up to your system and actual operation. As a first step, I'd suggest you to try "time ls /aufs" or your actual operaion with/without udba=notify. > Is there a way I can reduce the aufs cache size so I can hit this warning > with better predictability? I'm trying to see which user process is touching > the file/dir bypassing aufs. Memory is maintained by a usual way. When a system thinks there is memory pressure, then it tries discarding caches first. You can customize the size of cache via /proc/sys/vm/vfs_cache_pressure. Note: - vfs_cache_pressure effects all over your system. Not aufs specific. - reducing the cache means your system has to access files and disks frequently. it may hurt the performance. J. R. Okajima ------------------------------------------------------------------------------ Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_sfd2d_oct
