Overwrite LTO tape

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Botolo
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Overwrite LTO tape

Post by Botolo » August 7th, 2012, 11:21 am

Hi, we are using SEP 4 attached to a single LTO Drive.
The media pool configuration is standard:

Media Stretegy: OLD
Change Strategy: TIME
Locked Days: 2

Every day my backup job write the daily tape in append, and now I'm out of space in each tape.
How can I set the media pool (or the single media) to overwrite its content after X days?
In alternative, there's a way to erase (manually or automatically) the tape content withour re-initialize it?

Thanks

jgb
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Re: Overwrite LTO tape

Post by jgb » August 7th, 2012, 2:24 pm

Hello,

if the end of the media (EOM) is reached, the media will be closed and a new one will be initialized for the pool. At this moment the 2 days lock (end of live -> EOL) starts. If you splitt a job over 2 medias, the counter for the first media will start at the end of the splitted backup job.

So normally the media will be EOL free 2 days after the last bit was written to the media. I you have FULL -> DIFF/INC chains, all medias in the chain must be save until the last saveset is EOL free. You can see the EOL in the GUI under "components" -> "media" in the column "locked until".

jgb

Botolo
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Re: Overwrite LTO tape

Post by Botolo » August 7th, 2012, 3:42 pm

Thanks for your reply, but the situation is a bit more complex.
Tonight will start a new job and I know that the next tape is writable (EOL expired 5 days ago), but it's also almost full. SEP will ask for a new tape and there will be nobody until tomorrow morning to do the change. In the meantime the job will expire.

So my question is: may I ask SEP to erase (or overwrite since the beginning) a tape?

jgb
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Joined: June 27th, 2011, 11:11 am
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Re: Overwrite LTO tape

Post by jgb » August 8th, 2012, 9:22 am

Hello,

Sesam locks the whole media, so you can't overwrite/erase a part of the media. This is "work as designed", because Sesam writes multiple streams (multiplex) at the same time to the media.

If possible, you can change the start time of your new day event from 8:00 AM to somewhere later. So the new day will not cancel the job and you can change the media in the morning.

jgb

Botolo
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Re: Overwrite LTO tape

Post by Botolo » August 9th, 2012, 7:57 am

Thank you, I just changed the newday start time to 11:00 am so the operatore can change the media and the job will have time to complete.
But this is still a problem during the week end job.

How do you handle this? New tape every week?
Instead of erasing the tape, may I set manually the EOM flag? If i understand well, an EOM tape after the EOL time will be overwritten.

jgb
Posts: 55
Joined: June 27th, 2011, 11:11 am
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SEP sesam: Software

Re: Overwrite LTO tape

Post by jgb » August 9th, 2012, 8:43 am

Hello,

the solution depends on the amount of data you must backup.

If you know that one Tape have enough space for a FULL backup, the best way is to use a new tape every friday evening. You can switch off the new_day event for sunday and saturday, so the job can run over the weekend.
If you need more then one tape for a FUll -> buy a loader.

Sesam overwrite only EOL free medias. In a single drive environment, Sesam expect the last used media (active media -> blue padlock) in the drive.

If this media is in drive, sesam appends the saveset.

If another media is in the drive, sesam looks in his database, if the media is EOL free.
If YES, the old active media will be closed and the media is locked (red padlock) and the media in drive will be initialized (all data on media will be deleted) and the media becomes the active media (blue padlock)
If NO, Sesam will ask for another (EOL free) media.

jgb

Botolo
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Re: Overwrite LTO tape

Post by Botolo » August 9th, 2012, 9:18 am

Thanks again :)

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