On 03/21/2011 06:25 PM, J. Bruce Fields wrote:
On Mon, Mar 21, 2011 at 01:27:05PM +0100, Dennis Jacobfeuerborn wrote:
On 03/21/2011 04:09 AM, NeilBrown wrote:
On Mon, 21 Mar 2011 03:24:50 +0100 Dennis Jacobfeuerborn
<d.jacobfeuerborn@xxxxxxxxxxxx> wrote:
Hi,
I have a storage system that is exporting many directories to multiple
clients resulting in a lot of mountpoints (156) on each client. What I'm
trying to do is to create a single directory on the server and then use
mount --bind to mount all the different directories (which are stored on
different LVM volumes) into this single export directory and finally export
this directory to the clients.
Now the exports man-page mentions the crossmnt option but it also mentions
that it cannot be used if I want to export the directory to multiple
clients. Is there another way to accomplish something like this?
Just export the top directory with 'crossmnt' - it should work fine.
The 'multiple clients' thing only affects 'nohide' and I think it only
affected it back in 2.4 days.
Lots changed with 2.6, but maybe not enough of the man page changed :-(
So try with 'crossmnt' and if it doesn't work, then come back with details.
I've tried this now but it doesn't seem to work. This is the setup so far:
===========
On the server I've created the bind mounts like this:
/mnt/vg0/vol01/country/de/a on /exports/country/de/a type none (rw,bind)
/mnt/vg0/vol03/country/de/b on /exports/country/de/b type none (rw,bind)
...
Then I put the following line in /etc/exports:
/exports 192.168.0.0/255.255.255.0(rw,anonuid=96,anongid=96,secure,no_root_squash,wdelay,sync,crossmnt,no_subtree_check)
additionally these exports exist for each volume:
/mnt/vg0/vol01/country 213.131.252.0/255.255.255.0(rw,anonuid=96,anongid=96,secure,no_root_squash,wdelay,sync)
I'm a bit confused by the paths and ip blocks:
- You want to export the path that the client sees
(/exports/country/whatever), not the original path
(/mnt/vg0/...).
- If you expect clients to be able to traverse from /exports/ to
filesystems underneath, then you'd want to make sure /exports/
is exported to anything that the filesystems underneath are.
The /mnt/vg0/volXX exports are currently used to export each filesystem
containing letters individually. On the client I then mount each letter
individually which means access to each mountpoint doesn't have to traverse
filesystem boundaries on the server but it also means I end up with 156
individual mountpoints which is a pain to deal with. I had to write a
script that runs a loop mounting 5 letters then waiting 30 seconds then
mount the next 5 letters etc. If I try to mount these in one go about 10
mounts work fine but then I only get errors. Apparently the server can only
handle so many mounts in a certain timeframe (socket timeouts?)
That's why I'm aiming for consolidating the letters on the server using
bind mounts and then just mount the country directories leaving me with 6
mountpoints per client which would be *much* easier to handle.
The 192 IP range was a mistake and that should be the same 213 range as the
/exports export. If I can get this working then I plan to eliminate the
individual /mnt/vg0/... exports if they are not needed.
But actually you should only need the first /exports entry; filesystems
underneath should inherit export options from the parent.
This is what /var/lib/nfs/etab says for /exports after an exportfs -r:
/exports
213.131.252.0/255.255.255.0(rw,sync,wdelay,hide,crossmnt,secure,no_root_squash,no_all_squash,no_subtree_check,secure_locks,acl,mapping=identity,anonuid=96,anongid=96)
When I mount this I can see the proper subdirectories until I get to the
bind mounted letter directories which have their expected contents on the
server but appear empty on the client.
Regards,
Dennis
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