Date: Fri, 25 Dec 1998 00:03:06 -0500 From: Matthew Patton <patton@sysnet.net> To: freebsd-questions@FreeBSD.ORG Subject: NFS loopback mounts Message-ID: <l0311070cb2a8c196440e@[192.168.1.10]>
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I didn't see a forum on NFS specifics, so here goes. Apparently doing something like this is not a good idea under heavy NFS IO with big files. [fstab] >/dev/da0s1e /export/1 ufs rw 3 2 >/dev/da0s1f /export/2 ufs rw 3 2 >/dev/da1s1a /export/3 ufs rw 2 2 >localhost:/export/1/FreeBSD /usr nfs rw 0 0 >localhost:/export/2/FreeBSD/src /usr/src nfs rw 0 0 >localhost:/export/3/FreeBSD/ports /usr/ports nfs rw 0 0 >localhost:/export/3/home /home nfs rw 0 0 [exports] >/export/1 -alldirs -maproot=root >/export/2 -alldirs >/export/3 -alldirs I was doing a 'make update' (cvsup) on /usr/src and NFS consistantly went out to lnuch on fortunes.dat (first file of notable size). Whatever it did, it took out all NFS exporting which led to hung machines on my little network. Doing a 'make update' on another box, which NFS mounts practically everything off the server (s/localhost/nfsserver) works wonderfully. So are loopback mounts dangerous? Did I hit some sort of race condition by double mounting? My idea was that I could sit down on any of my hosts and expect to see the same FS layout. This also necessitated some /etc/rc edits to start nfsd VERY early in the process and a staticly compiled portmap installed in /sbin, etc. I'm beginning to think this was a bad move afterall and that I should just dedicate the box to NFS and not play fancy games with mount points. Now onto a mountd question. I've noticed the different behavior exhibited by the 3 more popular free unix's. If no host is specified in /etc/exports, OpenBSD tosses the line, FreeBSD defaults to everyone (with whatever options provided), and Linux uses everyone but explicitely changes the mount type to be anonymous (nosuid, nodev etc). I think the Linux guys for once came up with the best solution. Is there any interest in folding in the Linux everyone=anonymous behavior? Linux also lets you specify a raft of options on the server side such that I don't have to specify (ro,nosuid,nodev) on each and every client. The Free/OpenBSD syntax seems rather backward/limiting by comparison. Likewise Free/OpenBSD lack the ability to export filesystems except at their mount points. Right now I have to export all of /export/2 (above) with the -alldirs flag instead of something like /export/2/FreeBSD -options. Again, is there any interest in adding such functionality? Please don't take this as a knock against the *BSD family. I'm a HUGE proponent of the platform and run exactly 1 Linux box out of the dozen or more hosts under my control. If there is sufficient interest (or maybe even if not) I intend to generate appropriate diffs at some later point in time. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message
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