NFS and /etc/exports

[Dan Nelson]

In the last episode (Apr 14), Alfred Perlstein said:
> * Robert Blayzor <rblayzor.bulk at inoc.net> [080414 06:07] wrote:
> > On Apr 14, 2008, at 7:02 AM, Nawfal bin Mohmad Rouyan wrote:
> > >I'm using TCP and the entry in /etc/fstab on all clients is as below:
> > >
> > >build:/usr/ports        /usr/ports      nfs tcp,intr,nfsv3,-w=32768,-r=32768,rw,noauto      0       0
> > >build:/usr/src          /usr/src        nfs tcp,intr,nfsv3,-w=32768,-r=32768,rw,noauto      0       0
> > >build:/usr/obj          /usr/obj        nfs tcp,intr,nfsv3,-w=32768,-r=32768,rw,noauto      0       0
> > 
> > Are -r and -w really needed/useful for TCP mounts?
> 
> yes.

This is interesting: according to mountnfs() in nfs_vfsops.c, those are
already the kernel defaults:

    if ((argp->flags & NFSMNT_NFSV3) && argp->sotype == SOCK_STREAM) {
        nmp->nm_wsize = nmp->nm_rsize = NFS_MAXDATA;
    } else {
        nmp->nm_wsize = NFS_WSIZE;
        nmp->nm_rsize = NFS_RSIZE;
    }

$ grep nfs_maxdata /sys/nfs/*
/sys/nfs/nfsproto.h:#define     NFS_MAXDATA     32768

But it looks like /sbin/mount_nfs always overrides them to NFS_WSIZE
and NFS_RSIZE (both 8K) in its nfsdefargs struct.

-- 
	Dan Nelson
	dnelson at allantgroup.com