zfs discuss - Nov 2007 - Questions from a windows admin - Samba, shares & quotas

Hey folks,

This may sound a little crazy, but I''m a long time windows admin
planning on rolling out a Solaris server to act as our main filestore, and I
could do with a bit of advice.

The main reason for switching is so we can use snapshots.  With Samba and
Microsoft''s Shadow Copy Client we can backup everybody''s files
and give users the power to restore files themselves.  That plus the other
benefits of ZFS mean we''re seriously looking into this.  However, there
are one or two side effects...

I''m more than a little concerned about how we go about creating user
profiles and managing quotas.  On a windows server this is easy.  As you create
a user account the appropriate folders are created for you.  So long as you have
the right permissions on the parent folder, all those folders inherit their
permissions automatically, and since quotas work per user, that''s
automatic too.

The question is, can I do anything to automate all this if I move to Solaris?

We''ve got to use ZFS to get the benefits, but that doesn''t
have user quotas so I''ll have to script the creation of a filesystem
for each user.  First of all, if I have multiple filesystems, can I still share
those out under one path?  ie:  each user has a home folder of
\\server\share\username, can I still do that when every
''username'' is a separate filesystem?

Then, if that''s possible, is there any way I can make the creation of
these filesystems automatic?   What I''m thinking is that I''ll
need a parent filesystem for these to inherit quota settings from, and that will
be the ''share'' location above.  Now, when windows creates user
accounts, it will automatically create subfolders in that parent filesystem to
act as home directories.  Would I be able to write a script to watch that
filesystem for new subfolders and have it automatically delete the subfolder and
create a filesystem in it''s place?

And can I set permissions on a filesystem?  Could the script to that too?

If it works, while it may be a bit messy, there will actually be some advantages
over the windows quota system.  In windows, the quota is set by ownership of the
file.  If users move files between each other for any reason, or an admin has to
take ownership to change permissions that can get messed up, and it''s
nigh on impossible to find out where all your space has gone if that happens.
 
 
This message posted from opensolaris.org

Well, it looks like I''ve solved the question of whether you can
auto-create the folders.  There''s a nice little samba script that you
can add to the share to do it for you:
>From http://www.edplese.com/samba-with-zfs.html
Samba''s root preexec share parameter can really come in handy when
setting up user home directories. Here we tell it to automatically create a ZFS
filesystem for every new user, set the owner, and set the quota to 1 GB. This
can easily be expanded to other filesystem properties as well.

Create a file /usr/bin/createhome.sh:

#!/usr/bin/tcsh
if ( ! -e /tank/home/$1 ) then
  zfs create tank/home/$1
  chown $1 tank/home/$1
  zfs set quota=1G tank/home/$1
endif

Modify smb.conf and modify [homes] to resemble:

[homes] 
  comment = User Home Directories 
  browseable = no 
  writable = yes
  root preexec = /usr/bin/createhome.sh ''%U''
 
 
This message posted from opensolaris.org

Yes it will work, and quite nicely indeed. But you need to be careful.

Currently ZFS mounting is not "instantaneous", if you have like say
30000 users, you might be for a rude surprize as system takes its own merry time
(~ few hrs) mounting them at next reboot. Even with auto mounter, things
won''t be so fast.

ZFS philosophy of "helluva tons of filesystems" breaks a lot of tools
made with assumption of "who would ever need more than 4 filesystems
?".

To test it, create $NUM_USERS filesystems, reboot the server and see if
everything comes up ok and in acceptable time.
 
 
This message posted from opensolaris.org

Yeah, I''d seen that, but we''re only going to be running 100
users so the boot time shouldn''t be too bad. :-)
 
 
This message posted from opensolaris.org