>Originally, we had the tape settings to high, allowing the
>DLT 7000 drive with DLT IV tapes, 34,000 megs with a filemark
>of 8k. ...
Those numbers seem reasonable. Why do you think they are too high?
Are you using hardware compression (put a different way, what device name
are you using for the tape drive)? Are you using software compression?
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I considered these numbers too high because of the end of tape errors.
The magic word assume factors in there, but I don't want to say it
out loud.
The tape device I am using is 0lbn. We are using software compression
on the dumps.
>That began to fail when the amount of data reached
>a significant size. ...
What do you mean by "significant"?
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The original number of disks and volume of information we
were archiving was small, so no errors, when we started
adding more disks, the system eventually began showing
problems. "significant" was around 40 gigs, ie around 20
compressed.
>We got the traditional
>"*** A TAPE ERROR OCCURRED: [[writing file: short write]]."
>The filemark was killing us as was the length of the tape.
The filemark and length of tape values are **only** used by Amanda to
do the estimates. Once the actual backups start, Amanda keeps writing
until it gets an error. So when it reported the short write, that's
exactly what it meant -- you banged into physical end of tape.
There should have been a line something like this in the NOTES section:
taper: tape 041138/champion kb 43321088 fm 34 writing file: short write
---------------
Our last short dump line:
taper: tape VOL2 kb 19915968 fm 99 writing file: short write
>So, we ran the tapetype program and got a new tape size of
>19,457 megs. Now this has failed us with a short write.
That looks like you used the wrong density or forced it on the front
panel. What device name did you use? Did you make certain the tape
mounted at 35.0 GByte density?
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The device name we use is /dev/nrst1. As for the tape mounting at 35.0 gig
density, I did not consider any change in it since Amanda was mounting
the tape (again, the tricky word assume creeps in)
Michael Campfield
