Previous posts from various people:
> > > But ... NBU (at least version 6.0) attempts to estimate the
> > > size of the backup and make suer there is enough room on the DSSU to
> > > handle it. What happens when the free space reported by ZFS isn't
> > > really the free space ?
> > Regarding the question asked below namely "What happens when the free
> > space reported by ZFS isn't really the free space ?", is there an open
> > bug for this ?
As others have said, not a ZFS bug, but a feature :-) Of
course, this behavior can be eliminated using ZFS reservations. My
comment was regarding the utility of using one ZFS pool to contain
MULTIPLE NBU Disk Stage Storage Units ... I just don't see the utility
there and I do see a downside.
> The NetBackup server scans a backup client system,
> It determines it will need 600gb of disk space on the disk store.
> It stats the zfs volume and sees there is 700 gb free (enough for the
> backup)
> Starts writing 600gb over multiple hours.
> in the meantime, 500gb is used elsewhere in the pool.
> NetBackup Fails differently that on vmfs+vxvm in this case?
>
> Isn't it NetBackups issue to make sure that it has reserved diskspace or at
> least checks for space _as_ it writes?
If a disk stage fills during a backup (and there is nothing to
prevent another application from filling it either) it first triggers
DSSU garbage collection to remove the oldest backup images that have
already been duplicated to other storage, if that does not succeed in
freeing up enough space (and I have seen it trigger GC multiple
times), then I have observed two different behaviors (probably related
to differing patch versions):
1. backup fails with a 129 error
2. backup is continued on tape media
This latter 'solution' ends up creating a unusable backup
image as NBU now doesn't know how to deal with an image that crosses
storage units, but that is very off topic for this list :-)
My question was more toward how NBU will deal with the apparent
SIZE of the DSSU on ZFS changing on a frequent basis.
--
{--------1---------2---------3---------4---------5---------6---------7---------}
Paul Kraus
-> Sound Designer, Noel Coward's Hay Fever
@ Albany Civic Theatre, Feb./Mar. 2008
-> Facilities Coordinator, Albacon 2008
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