Re: ontape back-up/restore to remote device
The following reply from David was incorrect:
for the backup there is only one open and one close
only at restore time, two open calls occur in the described manner.
David Williams wrote:
>
> In article <34650EED.7ECD@netcomuk.co.uk>, Neil Truby
> <ntruby@netcomuk.co.uk> writes
> >John Miller wrote:
> >>
> >> Neil:
> >>
> >> On a restore the tape is open, read to verify that it has the correct
> >> information,
> >> closed to reposition at the begin of the tape, then re-openned. If the
> >> close
> >> did not get completed by the tape device by the time the open is issued any
> >> subsequent reads fail. There is an easy solution to this(if I remeber my
> >> shell script):
> >>
> >> 1. Create a shell script (lets say /work/bin/tape_wait.sh)
> >> #!/bin/sh
> >> /usr/bin/sleep 60; rsh $*
> >>
> >> 2. now in you ontape environment set DBREMOTECMD
> >> to /work/bin/tape_wait.sh
> >>
> >> Hope this helps,
> >> John Miller
> >
> >Thanks John. I had subsequently worked out that the problem was the
> >/dev/rmt/0n (no rewind) device. It works fine with /dev/rmt/0.
> >Informix tech. support told me that this was tough - ie , even on a 40G
> >DLT tape, you can only have one OnLine archive, and it must be the first
> >archive on the tape.
>
> Correct, Ontape
>
> a) open the tape device
> b) writes a tape header to the device
> c) close the device....AND EXCPECTS IT TO REWIND THE TAPE ONCE IT IS
> CLOSED I.E. A REWIND DEVICE RATHER THEN A NO-REWIND DEVICE.
>
> d) opens the tape.
> e) reads the header from the tape (THIS WILL FAIL ON A NO-REWIND
> DEVICE)
>
> f) writes the archive to the tape.
>
> >
> >I'm not at work, so I can't look up DBREMOTECMD, which I've never used!
> >
> >Regards
> >Neil
>
> --
> David Williams