NFS: Maximum settings for rsize and wsize
by rnturn from LinuxQuestions.org on (#52WTA)
What are the maximum settings for `rsize' and `wsize' when mounting NFS filesystems?
I've seen pages stating that Vers 2 NFS has a `8K' limit, Vers 3 & 4 have a `64K' limit, but I've also seen some benchmarking results that included test scenarios employing settings as high as `1M'.
I've been grepping the code under /usr/src/linux for clues about the absolute limit but have yet to see anything the defines the upper limit. I noticed that in /usr/include/linux/nfs_mount.h those two parameters are declared `int' (signed? weird) so I would assume that specifying `1M' is just a complete waste of time. On the other hand, I've actually mounted NFS filesystems using the sizes as `1M' (in both /etc/fstab and, lately, in /etc/nfsmount.conf) and seen no ill effects. The size didn't seem to be silently limited (nothing in /var/log/messages, at least) though, if it was being truncated, that wasn't apparent as `mount' showed the two sizes to be `1048576'.
Any kernel source gurus with pointers to the source or header file(s) that definitively set the limits?
TIA...
I've seen pages stating that Vers 2 NFS has a `8K' limit, Vers 3 & 4 have a `64K' limit, but I've also seen some benchmarking results that included test scenarios employing settings as high as `1M'.
I've been grepping the code under /usr/src/linux for clues about the absolute limit but have yet to see anything the defines the upper limit. I noticed that in /usr/include/linux/nfs_mount.h those two parameters are declared `int' (signed? weird) so I would assume that specifying `1M' is just a complete waste of time. On the other hand, I've actually mounted NFS filesystems using the sizes as `1M' (in both /etc/fstab and, lately, in /etc/nfsmount.conf) and seen no ill effects. The size didn't seem to be silently limited (nothing in /var/log/messages, at least) though, if it was being truncated, that wasn't apparent as `mount' showed the two sizes to be `1048576'.
Any kernel source gurus with pointers to the source or header file(s) that definitively set the limits?
TIA...