04-06-2011 02:02 AM
Dear Team,
1) Can anyone please elaborate on the concept of Freezing and Unfreezing of Tapes
2) I found this scenario when I was implementing at one of the client places
- I had inserted 12 New Tapes in my library and then erased it
- I created a volume pool which I wanted to use three tapes each for one week. So 3 tapes for 3 weeks. But when i tried to freeze the other two tapes which were for 2nd week and third week i could not do it. So is it so I can freeze the tapes only if data is written on it?
- I'm really new bie to this freeze and unfreeze funda
04-06-2011 02:33 AM
Dishant,
When you try to freeze a media, it checks the media ID in the EMM DB for completing the freeze request.
The reason you are unable to freeze the tapes is they are unassigned in EMM database. The tapes gets assigned in EMM DB when a media(unassigned) is requested for a backup.
04-06-2011 02:54 AM
1) So the tapes gets assigned in EMM DB i.e assigning it to a Volume Pool only when some data is written on it. Is it so?
2) Can you assign 3 new tapes to a Volume Pool.
04-06-2011 03:05 AM
04-06-2011 07:22 AM
i wanted to use three tapes each for one week.....
what you want to achive ? let us know in details
04-06-2011 07:30 AM
1) yes, media can be Frozen after it is Assigned. Assigned media has been allocated and usually* has data on it. Media is in a Volume Pool whether assigned or not.
2) yes, you can assign new media to any Volume Pool. Default pool is Netbackup. Many admins create a Scratch pool and make that the default.
* if tape has immediate write errors it might be Assigned with no data
04-06-2011 07:44 AM
I agree with above comments - allow NBU to manage media the way it does.
Study and understand how NBU selects and uses media and ensure you have enough tapes to satisfy requirements. Don't try to micro-manage the system to fit in with the number of tapes.
Some reading matter:
About selecting media in robots on Windows.
About selecting media in standalone drives on Windows.
About selecting media in robots on UNIX/Linux
https://www-secure.symantec.com/connect/blogs/understanding-how-netbackup-writes-tape
https://www-secure.symantec.com/connect/blogs/netbackup-and-just-how-multiple-streams-tape-drive-works
04-06-2011 11:33 AM
Apologies guys, I am on holiday, so am skiping reading all of this post ...
Regardng freezing media, there is only one answer - never never do it manually. I really don't understand why there is an option to freeze manually and I persnally think it should be removed as it causes more problems then it solves - why you may ask.
If NBU freezes a media, we know why, usually it has had x errors in y hours (3 and 12 by default), this can be investigated as necessary.
Sometimes many media get frozen at once, posible a config isue perhaps, again this is usually spotted and can be acted on.
Next a well meaning admin freezes a handful of media, then perhaps a few more, then after a while perhaps they leave going to a new job. Then we are left with a number of media that we have no idea about.
If you wish to save data on media - there is only one answer, extend the expire time. If you wish to stop a tape being used till it expires, suspend it. If you wish not to use a tape ever agan, suspend it and set the expire time to infinity.
Martin
04-06-2011 11:54 AM
Hope this will help you
A media being frozen does not necessarily mean that the media in question is defective. Freezing media is a safety measure taken by the NetBackup application to help prevent further errors, drive damage, or possible data loss.
Investigate if there is any pattern to the media IDs, tape drives or media servers involved when media are frozen