Backup wont append to tape

[Matrixdot]

hi Guys,

Version 10.1
OS w2k3

We seem to have an issue appending our backups. We have an overwrite protection period of 1 week and an append period as infinite allow append.

When i came in this morning i saw that the backups were in a queued state and i naturally thought no scratch media but when i looked at our volumes there were minimum data written to the tapes to the likes of a few megabytes. We have about 20 servers backing up and in the week we run differentials with Full backups on weekends using another media set.

I can see my media as appendable but when i try kicking of a manual backup it just goes in a queued state. I had a look at the options and played around there as well changing the backup option the overwrite media and append to media and still the issue persisted.

Any other ideas or questions are highly appreciated.

I had to change the overwrite to zero currently just so i could have some backups.

Regards,

Jerome

[Colin_Weaver]

The Overwrite period is fixed in length but is not fixed in terms of it start time as that depends on when the last data write occurs on the media in question.

For example Media Set with overwrite protect of 1 week and Infinite Append
Weekly jobs starts at  18:00 and runs for 4 hours ending at 22:00 - at which point job is rescheduled to start again at 18:00 (almost but not quite 1 week later than the end of the job)
Overwrite Protection of 1 week however means that the tape will only be available at 22:00 1 week later so when the job starts it can't use the tape and goes and finds another

Another example: You want your tapes to be appended to Monday through Thursday but you run a weekly backup on a Friday using a different set and your want the tape first used on Monday to be available on the next Monday

You set Append to 4 days (for Mon-Thursday, but set the overwrite protect to 1 week.)
Tape used by Monday job is not filled, but Tuesday Append job fills the tape and then uses another tape - the first tape then becomes overwritable 1 week after the time in Tuesday job when it was last written to - which again would cause the media not to be available till after the Monday of the next week.

Basically your overwrite protection has to be based on removing the time taken when the tape was being written to otherwise the tape will still be overwrite protected.

First Example would therefore need you to set overwrite protection of 6.5 days (in hours)
Second example would need you to set overwrite protection of 2.5 days (to cover for the possibility that you might append to the tape for 4 days.)

There is a reasonably good drawing in the media Managerment Chapter of the Admin guide that explains the sliding start time for the overwrite protection setting ) Note the append setting applies from when the tape is first overwritten and does not move.

One side point - do not allow appends to keep running forever with spanning from one tape to another as they fill - this is a recipe for an infinitely large media family and possible restore issues if the media family is missing media (from a sequence) at a later date, New families are started when a tape is overwritten (either as an overwrite job or when an append job can't find appendable media and swicthes to start as an overwrite)

[Symboy]

.Thanks Colin for explaining the media concept so well.

Matrixdot , Please  confirm if you have any alert for the media in the alerts tab.

[Matrixdot]

Thanks for the speedy response Colin.

We have had it like this forever and a day and never a issue, as things stand right now my allocation date is today as it had writes to it as it was set to zero as i needed to do my backups.

I changed my Overwrite protection to 6 days and my appendable days to 5.

This should allow me to be able to append until the 20th without overwriting any tape and on 21st allow tape to be overwritten?

However when i run a backup now it goes into a queued state, requesting scratch or overwritable media?

Seems like a bug to me.

Regards,

Jerome

[Matrixdot]

Thanks for the speedy response Colin.

We have had it like this forever and a day and never a issue, as things stand right now my allocation date is today as it had writes to it as it was set to zero as i needed to do my backups.

I changed my Overwrite protection to 6 days and my appendable days to 5.

This should allow me to be able to append until the 20th without overwriting any tape and on 21st allow tape to be overwritten?

However when i run a backup now it goes into a queued state, requesting scratch or overwritable media?

Seems like a bug to me.

Regards,

Jerome

[Ken_Putnam]

I changed my Overwrite protection to 6 days and my appendable days to 5.

This should allow me to be able to append until the 20th without overwriting any tape and on 21st allow tape to be overwritten?


Not quite

every time you append, the OPP is reset as of the time the media set is closed.  So if you create a tape today (the 15),   the OPP will be the 21st

If you append on the fifth day ((the 20th), the OPP will be the 26th

[Colin_Weaver]

The "allocated date" only affects the append period. The overwrite period is based on when data was last written (so probably the modified date)

If you append to the 20th with overwrite protection set to 6 days you will ONLY be able to overwrite the media on 26th - this is assuming you actually do append to the media on the 20th.

[Matrixdot]

Thanks Colin,

So if i set my overwrite protection to say 2 weeks and append to infinite, shouldnt it allow my backups to continue using those tapes? We always had it at 1 week and infinite append which was never an issue. now it wont allow me to append even with minimum write to the tapes.

Ps. i just changed the append period to see how it would behave.

[Ken_Putnam]

So if i set my overwrite protection to say 2 weeks and append to infinite, shouldnt it allow my backups to continue using those tapes? We always had it at 1 week and infinite append which was never an issue. now it wont allow me to append even with minimum write to the tapes.

With an OPP of 2 weeks, and an APP of Infinite, you should always be able to append, assuming there is room on the tape, but will not be able to Overwrite until two weeks after the last append job finishes

[Matrixdot]

Thanks Ken,

This is the way we always had it. OPP 2 weeks and an APP of infinite but it doesn't want to backup and the job just goes into a queued state.

The active alert only requests for a scratch or overwritable media to be loaded.

What i saw was that once my tapes had data on it wont load the tape again even thought only a few megabytes are on it. So that leaves me with a bunch of tapes in the library with little data and plenty of available space.

Not sure what else to try here so the assistance and input i receive here are much appreciated.

 

[Ken_Putnam]

Do you ever run an Overwrite job against this/those tapes?

It is sounding like the tapes have filled up, and thus are no longer APPENDABLE regardless of the OPP and APP settings

[Matrixdot]

The tapes are virtually empty only a few Megabytes written on them

[Colin_Weaver]

So are your jobs set to Append at Start or Overwrite at start?

Note if the answre is Append and you media list shows appendable media then you may need to log a proper support case as there is something odd going on

[Matrixdot]

Its set to append.

I even tried different settings but to no avail.

[Matrixdot]

I made the change and it seems to backup so thanks guys.

I wonder why this has never caused an issue before as the settings have remained the same as far as I know.

Anyway, thanks for the kind assistance

[Ken_Putnam]

Just out of curiosity, what changes did you make?