Hey,
I did a similar test a couple of months ago, albeit on a smaller system, and 'only' 10,000 users. I saw a similar delay at boot time, but also saw a large amount of memory utilisation.
I didn't notice the major memory usage, but the box had no other use, than to mount these mass of empty file systems. But I might've missed it, the I/O to mount them was HEAVY!
Around the same time, Casper Dik mentioned the possibility of automounting zfs datasets, as well as the possibility of cool stuff like *creating* zfs datasets with the automounter.
I suppose i could do that, but that feels a bit icky, sorry for the lack of eloquent wording, but that's pretty much how it'd feel, i suppose, one could create /data/sub/ and tell it not to mount the sub piece, and create the automounter to control the sub piece. ( and any file systems sub that )
One thing that hasn't been touched on is how one would back up a system when some (or most) filesystems are unmounted most of the time.
Well technically, as far as i understand it, surely when the backup software accessed the device, it'd mount it, so as it went along, it'd mount the filesystems, and then for the `zfs send` thing, technically, that should be possible without the filesystem being mounted, same with snapshots, although i'd shudder to think what a snapshot per filesystem for backup would be like. But that said, i've got another quesiton, is it possible to recursively send a pool ? ( with zfs send ? )
Is is possible to make a backup and/or take a snapshot of an unmounted dataset (and if not, is that a future possibility)?
I believe it's possible to snapshot unmounted devices, as well as zfs send them, but i could be wrong, although i really don't think that it should make that much of a difference. As far as i remember, ZFS snapshot/send/etc... access the device, not the filesystem. P -- Patrick ---------------------------------------- patrick <at> eefy <dot> net _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
