dump -L

[Vince]

Victor Sudakov wrote:
> Colleagues,
> 
> Right now I am watching a dump:
> 
> [root at admin ~] dump -b64 -5Lau /home
>   DUMP: Connection to big.sibptus.tomsk.ru established.
>   DUMP: Date of this level 5 dump: Sat Aug 18 14:02:16 2007
>   DUMP: Date of last level 0 dump: Sun Aug 12 11:10:56 2007
>   DUMP: Dumping snapshot of /dev/ad0s2f (/home) to /dev/nsa0 on host big
>   DUMP: mapping (Pass I) [regular files]
>   DUMP: mapping (Pass II) [directories]
>   DUMP: estimated 3249348 tape blocks.
> 
> at the same moment:
> 
> [root at admin ~] snapinfo -v /home
> /dev/ad0s2f mounted on /home
>         no snapshots found
> [root at admin ~] ll /home/.snap/
> total 0
> [root at admin ~]
> 
> 
> Is this normal? Does it mean that dump is not really dumping a
> snapshot though it says it is?
>

man dump (the section regarding -L) says
"The snapshot is unlinked as soon as the dump starts, and is thus 
removed when the dump is complete." What this means to you is that the 
snapshot is only visible on the file system for as long as it takes dump 
to start reading from it, dump will have an open filehandle to the 
snapshot so it can be unlinked from the filesystem and as soon as dump 
closed its handle then the snapshot is removed. Similar to when you 
delete a large logfile a program has open and forget to HUP/stop/restart 
the program, the logfile's diskspace isnt released until the the program 
closes its file handle.

Vince