We found the cause of this problem. It seems that the directory creation was failing when the mod_disk_cache was trying to create the subdirectory structure to store the header and data content . The reason this failed was because mod_disk_cache had already created a large number of directories and that number exceeded the max link count allowed on a ext2/ext3 file system, i.e. 32000.
So i guess the solution here would be to use a different file system ,i.e ext4 or reiserfs or perhaps configure disk_cache to use shorter directory lengths and more levels.
-M Manik Taneja wrote:
Hi,I have an apache server that is configured as an HTTP proxy, i.e. mod_proxy is enabled. Along with this i have also enabled mod_disk_cache and mod_mem_cache. The system that we are using in ubuntu-server with 2.6.24 linux kernel versionWe are doing some load tests on this system with web-polygraph, not a very heavy load but around 120 tps. Initially we see that the apache proxy server is able to cache 55% of the objects but as the tests go on for more than 1/2 hr the cache hit ratio drops to around 1-2%. We debugged this issue and we saw that after a while there are no objects being written to the disk. All the cache hits come out of the mem_cache. After enabling debug logging we saw a large number of the following error messages being logged.[Sat Sep 06 09:47:15 2008] [warn] (20)Not a directory: disk_cache: rename tempfile to datafile failed: /cache/aptmpAglkI4 -> /cache/72kYIz/6OraHr/pEFUJY/ZWkw.dataI am not sure what a "Not a directory" message is supposed to mean, but i am guessing this happens because the directory inode is some sort of inconsistent state. We initially saw these errors on a ext3 filesystem and so we created an ext2 fs, however these error messages don't seem to go away.I am wondering if this is a known problem or someone who has seen these messages before and knows of a work-around can help us.Oh and the apache version that we are using is 2.2.9 . TIA Regards, Manik ---------------------------------------------------------------------The official User-To-User support forum of the Apache HTTP Server Project.See <URL:http://httpd.apache.org/userslist.html> for more info. To unsubscribe, e-mail: users-unsubscribe@xxxxxxxxxxxxxxxx " from the digest: users-digest-unsubscribe@xxxxxxxxxxxxxxxx For additional commands, e-mail: users-help@xxxxxxxxxxxxxxxx
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