Re: [zfs-discuss] ZFS versus VxFS as file system inside Netbackup 6.0 DSSU

2008-02-13 Thread Sri Sudarsan
Selim,

Symantec does support ZFS as DSSU targets.  I've also seen a SUN white 
paper outlining the use of Thumper (Sun X4500) as a NB 6.5 media server, 
where the best practice was to to configure multiple NB disk storage 
units to use a distinct ZFS file system. In this case, all the ZFS file 
systems serving as DSSUs utilized one zpool.

Hope this helps,

Sri

Selim Daoud wrote:
 unfortunately in this area, Symantec is not helping anyone. they even
 take their time to officially include zfs in their compatibility lists
 s-

 On Jan 16, 2008 1:26 PM, Paul Kraus [EMAIL PROTECTED] wrote:
   
 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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Re: [zfs-discuss] ZFS versus VxFS as file system inside Netbackup 6.0 DSSU

2008-01-15 Thread Sri Sudarsan
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 ?

Thanks,

Sri
Paul Kraus wrote:
 On 1/15/08, Selim Daoud [EMAIL PROTECTED] wrote:

   
 with zfs you can compress data on disk ...that is a grat advantage
 when doing backup to disk
 also, for DSSU you need to multiply number of filesystem (1 fs per
 stu), the advantage of zfs is that you don't need to fix the size
 of the fs upfront  (the space is shared among all the fs)
 

 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 ?

 We are using NBU DSSU against both UFS and ZFS (but not
 against VxFS) and have not noticed any FS related performance
 limitations. The clients and the network are all slower.

   

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