Unable to add data - media saturated

[Unimax]

Hi, 

This is the first time I'm asking a question and since I can't find my answer, it will ask it here.

I got a question. I use Backup Exec 12.5 and the way the backup is set is : 1 tape per day (monday to thursday) used for full backup. I also have 5 tapes for Fridays and 3 tapes for monthly. 1 tape for january-april-july and october, 1 tape for february-may-august and november and 1 tape for march-june-september and december. I have one task for the daily backups, 1 for the fridays and 1 for the monthly with respectives tapes associated.

Tapes are set to overwrite and there is not retention set. I manually change the tapes in the library.

Now my question. I have problem with 2 tapes. They are saturated and it is impossible to add new data even if they are set to be overwritable.

Is it because the tape has reached its end of life ?

This is a problem because one daily backup was complete on a tape used for monthly backup. (it used 2 tapes when normally it takes only 1)

Can anybody help me with this ?

Thanks,

[pkh]

You got to look at the amount of data that is being backed up and see whether they fit onto one of your tape.  It could be that the amount of data that is being backed up exceeds the capacity of your tape.

Also, if you are compressing uncompressible data, you could end up with more data on your tape than you start with.  See my article below

https://www-secure.symantec.com/connect/articles/compression-short-explanation 

[Kiran_Bandi]

As pkh already said first thing you can verify is the amount of data you are backing up. If one media is not enough to write the data BE will use any other tape which is available in library. Because you don't have any overwrite protection on your tapes.

As you said it used 2 tapes and earlier it was using only one. So, i believe it is not a problem with media. Amount of data you are backing up may be increased. 

To keep BE away from using monthly/weekly tapes from using for daily backups either apply overwrite protection on those tapes or keep those tapes away from the library. Also you may have to give some more tapes to daily backups for successful backups.

To check about the media functionality right click on the media in question and click on properties. Under statistics look at errors. 

Regards..

[Unimax]

Thanks for the input. I appreciate the quick response. The amount of data was the first thing that I checked when I saw that 2 tapes were used. I would say that the amount of data is not changing a lot from day to day. A full backup is around 750GB-800GB and we use 1,64TB tapes so there is plenty of space for a daily full backup on 1 tape. 

This morning when I look at last night backup job, I got the same problem. The job used the Thursday tape and the Monday tape. Thursday is now tagged as "impossible to add -saturated media" (french translation). In french it is "Impossible d'ajouter - support saturé". As I was saying in my first post, all my media are set to Overwrite, and there is no Overwrite protection period set on the tape since I am removing the tape from the library after each backup...

Capacity used on the tapes are as follow :

Thursday : 760GB on 781,5GB with a compression ratio of 2,2:1

Friday : 751,8GB on 781,5GB with a compression ratio of 2,4:1

Monday : 134,6GB on 781,5GB with a compression ratio of 3,9:1

The other tapes are out of the library.

If I leave everything like this tonight, i deduct that Friday's backup will be done on Monday tape since the Friday tape is saturated.

Why is my tape not being overwritten since this option is selected ?

[pkh]

I think you are using LTO4 tapes.  When the box says 1.6TB, it means that you would get 1.6TB of compressed data on your tape provided you have achieved a compressioni ratio of 2:1.  The native or uncompressed capacity of the tape is only 800GB.  From your quoted statisttics, you are at the edge of your tape capacity.  For your Thu. tape, you actually have only 20GB of uncompressed space left on your tape.  It is not surprising that your data spill over to another tape.

[Unimax]

Ok. Thanks for your input everyone. After a discussion with Symantec Support, we have changed the amount of data that is backed up to a smaller amount (around 430GB) since we need to use only one tape.

Now I have another problem. Since my backup is set to append data and overwrite if no media is available, I am still facing the issue of the job taking 2 tapes when it should use only 1. 

I see this happening when a tape as been used for 1 or 2 backups and there is not enough space for the entire backup job when it starts. The job will finish to fill the tape and will use another tape, even if the tape is not in the same "media set". 

My question now : Is the tape unit supposed to continue to write data at the beginning of the tape or it is a normal behaviour that it take another tape to complete the job ?

Thanks.

[Ken_Putnam]

My question now : Is the tape unit supposed to continue to write data at the beginning of the tape or it is a normal behaviour that it take another tape to complete the job ?

This should actually be a new thread, but  Yes, this is by design  You can limit this by using the option to "use overwriteable medai in the target media set before scratch media,"

if an append job fills a tape, it will only continue on another, overwriteable tape,  If there is no tape available in the target media set, it will grab on from another media set. 

If it went back and tried to start writing from the start of the mounted tape, it would effectively quick erase the tape, and the first part of hte backup would be gone