Problems with Media Sets/Backup Strategy

[CFelder]

I am experiencing the "Media Full" problem where the tape is ejected and a request for a new media is made. I am new to this as well, but the append and overwrite schedules seem to complicate this process.

From the previous post and responses, I gather this is because of the append to media settings.

I don't have any issues or constraints with regards to purchasing additional tapes, I just don't think its necessary.

I swap tapes every night using one tape for each night. They are labeled "Monday"..........."Friday". I have a daily job that runs each night.

When I view the properties of my Media Set and a particular tape ( in this case the one labeled Monday) this is what I see.

Media Set:
Overwrite Protection period: 4 Hours
Appendable period: Infinite - Allow Append

Monday's Tape:
Overwrite Protection until: Overwritable
Appendable Until: Not Appendable (Media Full)

When Monday's tape is in the drive and the daily job runs Monday night, the data that is getting overwritten is last Mondays data, since I recycle the tapes each week. In this scenario, I'll always have the last weeks data right, albeit each day of the previous week would reside on its own tape. Wouldn't my scenario work error free if I change the overwrite settings to "None"?

Any assistance is greatly appreciated.

[RahulG]

The overwrite protection period which you have specified is less as its just four hours . So incase if you left the tape accidently in the drive the next time you run the job it would overwrite the information backed up.  you can increase the overwrite protection period accordingly
for example if you are want the monday tape to be overwritten on next monday
you can set an overwrtie protection perion to 6 day and appen period to 1 day on the media set . so every monday you monday tape would be overwriten .

[Ken_Putnam]

i am experiencing the "Media Full" problem where the tape is ejected and a request for a new media is made.

With this symptom, I would suspect that your jobs are Append rather than Overwrite, assuming that the data  backed up is less than the capacity of the tapes.  What kind of tapes do you use, and how much data is backed up before the "Insert Overwriteable media" is displayed

[CFelder]

HP Ultrium LTO. Capacity 400 GB. I'm trying to back up about 250 GB of data. When it stops it

I changed the Overwrite protection period to 6 days and the Append period to 1 day on the Media Set settings.

My last good backup was this past Friday. The properties on that tape say;

General
Overwrite Protection Until:7/17/2009 4:54:30 AM
Appendable Until: Not Appendable

Statistics
Hours in Use: 21.6
Data: 239.47 GB
Used Capacity: 178.7 GB of 195.8 GB
Available capacity: 17.07 GB
Total Capacity: 195.8 GB
Compression Ratio: 1.3:1
Bytes Written: 463.5 GB
Bytes Read: 357.8 GB
Mounts: 20
Seeks: 208

I think my confusion lies in the relationship between apend and overwrite.

The tape I have in now is labeled "Monday".  The properties on this one are;

General
Overwrite Protection Until: Overwritable
Appendable Until: Not Appendable (Media Full)

Statistics
Hours in Use: 20
Data: 250.25 GB
Used Capacity: 188.3 GB of 195.8 GB
Available capacity: 7.41 GB
Total Capacity: 195.8 GB
Compression Ratio: 1.3:1
Bytes Written: 370.8 GB
Bytes Read: 369 GB
Mounts: 24
Seeks: 202

I have another concern now. I run two jobs on the same tape. The one we've been discussing is called Daily. The other one I run is called Exchange. The second job is backing up data on a totally different server. Not much data there comparatively speaking (its about 4 GB). My question is will the second job completely overwrite the first one now that the the Media Set is overwritable?
 

[Ken_Putnam · Accepted solution]

I think my confusion lies in the relationship between apend and overwrite.

OPP is figured from the time that the last job on a tape (or BKF append family) is closed, and thus changes every time an Append job is run

APP   is figured from the time the first backup set is started on a tape and never changes

So if

OPP = 7 days, APP = 5 days

Job daily is defined as Append, runs Mon - Fri

Monday no appendable is found, new tape is Overwritten, Tue - Fri, job appends to the tape.  On Saturday the Append is now 0 , not appendable (it is more than 5 days since the first job ran)  but the opp is NEXT Saturday (7 days from today) not Monday (7 days from the original overwrite)


My question is will the second job completely overwrite the first one now that the the Media Set is overwritable?

if the job is APPEND and the same media set is used, absolutely not,   If however it uses a different media set, and if no appendable tapes in THAT set are found, and the tape just written is the only one Overwriteable, then yes it will overwrite the first job of the night.  If it can see anyother Overwritable tapes, it should use them first

If you have one tape for each night, I'd set the daily OPP to 6 days. APP to 1 day (or 12 hours, maybe)

[CFelder]

Yes thats what I did. I have one tape for each day Mon - Fri. I don't run any jobs on Saturday or Sunday as nothing happens on those days. So basically it is a 5 day rotation.

[CFelder]

If my backup is successful tonight I will mark this problem as solved.