How to invalidate NFS read cache?

Konrad Heuer kheuer2 at gwdg.de
Fri May 8 08:25:51 UTC 2009


Hello,

sporadically, I observe a strange but serious problem in our large NFS 
environment. NFS servers are Linux and OS X with StorNext/Xsan cluster 
filesystems, NFS clients Linux and FreeBSD.

NFS client A changes a file, but nfs client B (running on FreeBSD) does 
still see the old version. On the NFS server itself, everything looks 
fine.

Afaik the FreeBSD kernel invalidates the NFS read cache if file 
modification time on the server changed which should happen here but 
doesn't. Can I force FreeBSD (e.g. by sysctl setting) to read file buffers 
again unconditionally after vfs.nfs.access_cache_timeout seconds have 
passed?

Best regards

Konrad Heuer
GWDG, Am Fassberg, 37077 Goettingen, Germany, kheuer2 at gwdg.de


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