NOSKIP & SKIP make no difference to the amount of time backup take

Hi
I run a full backup once a month and a transaction log backup every 10 mins
through working hours for the remainder of the month until the backup is
re-initialised at th start of the following month.
I backup to virtual sql disk object devices.
As the month progresses the backup takes longer and longer whilst the amount
of data being backed up every 10 minutes cycle is always roughly the same.
its about 5 seconds for a backup on day 1, up to 5 mins at the end of the
month.
I noticed that NOSKIP was being used in the command - i changed this to
SKIP, but it made no difference in the amount of time the backup takes. Isnt
this suppoed to stop some sort of integrity scan on all other backup sets in
the archive?
full syntax of the backup command that runs now is:
BACKUP LOG [objectstore] TO [Backup_objectstore] WITH NOFORMAT , N
OINIT ,
NOUNLOAD , NAME = N'objectstore backup', SKIP , REWIND , STATS = 10
but as I say, the SKIP command instead of NOSKIP makes no difference.
whats going on here?
any help appreciated.
Thanks
Alastair.On Aug 1, 3:44 pm, Methodology <Methodol...@.discussions.microsoft.com>
wrote:
> Hi
> I run a full backup once a month and a transaction log backup every 10 min
s
> through working hours for the remainder of the month until the backup is
> re-initialised at th start of the following month.
> I backup to virtual sql disk object devices.
> As the month progresses the backup takes longer and longer whilst the amou
nt
> of data being backed up every 10 minutes cycle is always roughly the same.
> its about 5 seconds for a backup on day 1, up to 5 mins at the end of the
> month.
> I noticed that NOSKIP was being used in the command - i changed this to
> SKIP, but it made no difference in the amount of time the backup takes. Is
nt
> this suppoed to stop some sort of integrity scan on all other backup sets
in
> the archive?
> full syntax of the backup command that runs now is:
> BACKUP LOG [objectstore] TO [Backup_objectstore] WITH NOFORMAT ,
NOINIT ,
> NOUNLOAD , NAME = N'objectstore backup', SKIP , REWIND , STATS = 10
> but as I say, the SKIP command instead of NOSKIP makes no difference.
> whats going on here?
> any help appreciated.
> Thanks
> Alastair.
Noskip/skip does not make any difference on Backup time. It just
checks expiration date of backup sets. I just guess that the reason
may be that your disk gets fragmented after number of backups and that
may cause delay.|||Looking at the BACKUP commands you posted, which includes REWIND and
NOFORMAT, it looks like the backup goes to tape. When you referred to
"virtual sql disk object devices" I was not expecting that. Tapes are
not virtual disks, tapes are tapes.
I have seen that behavior when backing up directly to tape. The
problem in that case was reading the tape from the start to the point
where the prior backup ended. Lets consider that by the end of the
month there have been around 1000 log backups assuming a 5 day work
week and an 8 hour work day.
I suggest changing the REWIND option to NOREWIND. From the
documentation: "NOREWIND -- Specifies that SQL Server will keep the
tape open after the backup operation. You can use this option to help
improve performance when performing multiple backup operations to a
tape."
Roy Harvey
Beacon Falls, CT
On Wed, 1 Aug 2007 03:44:00 -0700, Methodology
<Methodology@.discussions.microsoft.com> wrote:

>Hi
>I run a full backup once a month and a transaction log backup every 10 mins
>through working hours for the remainder of the month until the backup is
>re-initialised at th start of the following month.
>I backup to virtual sql disk object devices.
>As the month progresses the backup takes longer and longer whilst the amoun
t
>of data being backed up every 10 minutes cycle is always roughly the same.
>its about 5 seconds for a backup on day 1, up to 5 mins at the end of the
>month.
>I noticed that NOSKIP was being used in the command - i changed this to
>SKIP, but it made no difference in the amount of time the backup takes. Isn
t
>this suppoed to stop some sort of integrity scan on all other backup sets i
n
>the archive?
>full syntax of the backup command that runs now is:
>BACKUP LOG [objectstore] TO [Backup_objectstore] WITH NOFORMAT ,
NOINIT ,
>NOUNLOAD , NAME = N'objectstore backup', SKIP , REWIND , STATS = 10
>but as I say, the SKIP command instead of NOSKIP makes no difference.
>whats going on here?
>any help appreciated.
>Thanks
>Alastair.|||On Aug 1, 4:37 pm, Roy Harvey <roy_har...@.snet.net> wrote:
> Looking at the BACKUP commands you posted, which includes REWIND and
> NOFORMAT, it looks like the backup goes to tape. When you referred to
> "virtual sql disk object devices" I was not expecting that. Tapes are
> not virtual disks, tapes are tapes.
> I have seen that behavior when backing up directly to tape. The
> problem in that case was reading the tape from the start to the point
> where the prior backup ended. Lets consider that by the end of the
> month there have been around 1000 log backups assuming a 5 day work
> week and an 8 hour work day.
> I suggest changing the REWIND option to NOREWIND. From the
> documentation: "NOREWIND -- Specifies that SQL Server will keep the
> tape open after the backup operation. You can use this option to help
> improve performance when performing multiple backup operations to a
> tape."
> Roy Harvey
> Beacon Falls, CT
> On Wed, 1 Aug 2007 03:44:00 -0700, Methodology
>
> <Methodol...@.discussions.microsoft.com> wrote:
>
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>
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>
>
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> - Show quoted text -
I dont have much idea about tapes but in BOL it says that
NOREWIND implies NOUNLOAD, and these options are incompatible within a
single BACKUP statement
and Methodology has specified also NOUNLOAD in the script.