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when the backup job will start exactly within the backup window..?

Created: 03 Jun 2010 | 11 comments

Hi ,
I face this quetion in interview...
can u plz tell me...
if we set the Backup window from 6PM to 5AM
with in this in what time the backup will start....?
and one more thing..
how much time to take the backup of 500gb data...?

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RabR's picture

I don't know too much about NetBackup - but I do use it.

As far as I know:

The backup should start at 6pm unless it is busy doing other backups, or other tasks which would mean the allocated resources are full. I suppose it depends on what else is set up inside the policy - number of clients, etc.

The time it will take to backup will depend on your hardware. Are you backing up to tapes? To disk? What's the speed of your tapes / disk / network gear. How long is a piece of string? :)

To give you an accurate reply to either of your questions I think you need to provide more information.

My two cents.


koya's picture

LTO 2 tape
T9840 B and C drives...
we hav to take the backup to tapes...

Gavrilov's picture

1. You can check this in the nbpem log but most likely  it wi'll start at 6 PM
2. LTO-2 will give you 40 MB/sec max. So if your clinet able to send data to the Media-server with such speed you may calculate speed. But really your speed will be less then calculated.



NetBackupTech's picture

Your backup has a window of opportunity to be run between 6PM and 5AM. If resources are available, 6PM will be the start time.
Should the job go queued before 5AM, it will still run- NBU won't kill a queued job once it's begun.

Backup speeds - Unix?
Check for the existence of these two tuning files (not there by default)

if not present
echo "262144" > /usr/openv/netbackup/db/config/SIZE_DATA_BUFFERS
(the size of the data buffer being used)
echo "16" > /usr/openv/netbackup/db/config/NUMBER_DATA_BUFFERS
(use a little math for this one- the total number of drives times the multiplexing setting on the storage unit- use factors of 8,16,32, etc)

No restarting is needed after adding these tuning files- and you'll get anywhere from 3 to 5 times the performance as you would out of the box

Andy Welburn's picture

won't kill a queued job once it's begun"

Status Code 196? A backup or an archive operation that the backup scheduler queued was not attempted because the backup window was no longer open.

If the job actually starts it will be fine, if it is still queued it will fail with EC196

J.H Is gone's picture

If you have a 6 pm start time, it will start the next time the nbpem does an Policy update - the interval by default is every 10 minutes.  So the job should start by 6:10 pm - it all depends on when that next scan interval comes around.  ( this is a global setting).

I don't have to know how to spell....I work on Unix.
NetBackup 7.0.1 - AIX & Windows

Marianne's picture

If I was asked those questions My answer would be:
1. Question: Frequency or Calendar? If frequency, the backup will go active when 'enough time has elapsed since the previous backup'. If frequency is set to one day (meaning once every 24 hours), and the previous day's backup only went active at 4am (network problems, device errors, etc...), the next backup will only go active at 4am.
If Calendar based, should go active at first nbpem cycle after 6pm, but not a good idea to have calendar based span midnight, especially for daily backups...
2. Question: How long is a piece of string? The time that it will take depends on transfer rate: a) read-speed of data from disk on client  b) Network transfer rate  c) Media server's ability to stream tape drives  d) tape drive capability

Supporting Storage Foundation and VCS on Unix and Windows as well as NetBackup on Unix and Windows
Handy NBU Links

J.H Is gone's picture

I was thinking the same thing, The easy answer was nbpem,
The correct answer needed more input, was a manual done, what version are you on, what is the frequency, are there enough drives, how many other jobs are running, and what is the multiplex set to..........  not an easy answer with just that little info.

And with the tape it is the same thing, network, fiber, speed, how many jobs are running, is the tape set to multiplex.... I am with you Marianne, I would need more info to make an informed answer.

I don't have to know how to spell....I work on Unix.
NetBackup 7.0.1 - AIX & Windows

Rajesh_s's picture

As mentioned earlier by Hinchcliffe by default NBPEM (NB policy execution manager) will trigger every 10 minutes . You can change that in Global Attributes tab in Master server properties by changing the "policy update interval" ..

Below is the technote on the same ..