Re: [Networker] Verifying data written
2006-10-31 15:24:45
> Uhh, the error underlying this is that data has been overwritten, and that's
> not recoverable.
Not if you weren't writing during the reset . Then nothing has been put on
tape, and I doubt
that any media index is updated either during a read
>
> SCSI resets will generally be caught by NetWorker and all savesets marked
> suspect anyway. There is some software out there (regularly for system
> health monitoring, ironically) which will simply try to open tape handles to
> check that things are working and will use things like /dev/rmt/0. The OS
> will rewind that as soon as it's closed. There's no error apart from a delay
> in accessing the tape drive during this time (a retryable EBUSY or similar
> when it encounters the file lock). NetWorker will generally check its
> position on tape before writing, but I'm sure there are a couple of instances
> where it just expects to be in the same place as before.
Actually the drive will generate an error but the driver usually ignores it as
it is
the same status that he drive will generate after a power on (Drive reset if I
remember rightly).
> 7.3 should get around this, but that means using 7.3. I'm not sure if its
> SCSI reserve is enabled by default or not. It won't block a reset, but it
> will block a rewind. If you're on HP, set the st_no_rewind (I think) kernel
> parameter to disable rewind-on-close devices, but this will only protect SAN
> tape drives in the event that software issuing (effectively) those rewinds is
> running on HP.
Yep.
Dag
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