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Home -> Community -> Mailing Lists -> Oracle-L -> linux memory: limiting filesystem caching
Hi all
I have several redhat blade clusters running 10.1.0.4 RAC on 2.4.9-e.43enterprise. All database storage is OCFS, with ext3 for backups, home dirs etc. The servers have 12GB of RAM, of which about 2GB is allocated to the database, which is fine. Linux, in its wisdom, uses all free memory (10GB in this case) for filesystem caching for the non OCFS filesystems (since OCFS uses directIO); so every night when I do a backup it swallows up all available memory and foolishly sends itself into a swapping frenzy; and afterwards it sometimes cannot allocate enough free mem for background processes. This seems to be worse on e43; I was on e27 until recently. Does anyone know how to control filesystem block caching? Or how to get it to de-cache some? For instance, I have noticed that gziping a file, then ctrl-C'ing it can free up a chunk of RAM, I assume it de-caches the original uncompressed file. But its not enough!
Rgds
Mark
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-- http://www.freelists.org/webpage/oracle-lReceived on Wed Jul 13 2005 - 02:32:56 CDT
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