On 7/25/06, Brad Plecs <[EMAIL PROTECTED]> wrote:
I've run into this myself. (I am in a university setting). after reading bug ID 6431277
(URL below for noobs like myself who didn't know what "see 6431277" meant):
http://bugs.opensolaris.org/bugdatabase/view_bug.do?bug_id=6431277
...it's not clear to me how this will be resolved. What I'd really like to see
is
the ability to specify where the snapshot backing store will be. (more
specifically, the
ability for the snapshot space to *not* impact the filesystem space).
Given the fact that you probably want this functionality quicker than
it is likely to be delivered in a supported version of Solaris,
perhaps you would be better off with two copies of the data. This may
or may not have a cost advantage over NetApp.
The idea is that you have two storage pools - one for live data, one
for backup data. Your live data is *probably* on faster disks than
your backup data. The live data and backup data may or may not be on
the same server. Whenever you need to perform backups you do
something along the lines of:
yesterday=$1
today=$2
for user in $allusers ; do
zfs snapshot users/[EMAIL PROTECTED]
zfs snapshot backup/$user/[EMAIL PROTECTED]
zfs clone backup/$user/[EMAIL PROTECTED] backup/$user/$today
rsync -axuv /users/$user/.zfs/snapshot/$today /backup/$user/$today
zfs destroy users/[EMAIL PROTECTED]
zfs destroy backup/$user/$lastweek
done
It's an ugly hack in that it doesn't use a lot of ZFS' goodness on the
live file system. However, it would provide many days (weeks?) of
space-efficient backups on the backup server. Obviously there is more
logic required for ensuring that the right number of backups are kept,
new and deleted users are dealt with appropriately, etc. The
block-level rsync mechanism may be useful, but it is unlikely unless
your users are using a lot of database files (oracle, dbm, etc.).
This hack does have the benefit that you get a copy of the data stored
safely somewhere else to give better disaster protection of the data,
assuminng the backup is on a different server somewhere else on (or
off) campus.
Assuming you go with something like this and the students have read
access to the backups, how long will it be until the students start
ciculating the script to automatically rotate their extra data in and
out of their home directory and backup directories so that they get 50
MB * "number of snapshots" of space? Back in the day, I had pitched
battles with a few people over print quotas and customized postscript
to lie about the number of pages. I won once I found a way to get to
the page counter on JetDirect cards. :)
Mike
--
Mike Gerdts
http://mgerdts.blogspot.com/
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