Transferring dump file to tape?

[Viren Patel]

> On Mon, May 16, 2005 at 11:36:18AM -0500, Viren Patel
> wrote:
>> Hello. I am using 'dump' to backup client filesystems to
>> a
>> disk file on an NFS mounted partition, e.g.
>>
>>    dump -0aLu -f /bk/var-20050516 /var
>>
>> Now I'd like to take the backup file (var-200500516) and
>> move it to tape (on the NFS server). However I'd like
>> the
>> tape to have the data just as if it had been created
>> directly by 'dump', e.g.
>>
>>    dump -0aLu -f /dev/nsa0 /var
>>
>> Any way to do this? I could use rdump/rmt to backup
>> directly to the remote tape, but I am doing it this way
>> to
>> do fast disk-based backups during night and move to
>> slower
>> tapes during day. For normal restores I can use
>> NFS-based
>> files but have tapes for single-user-mode type restores.
>> Thanks.
>
> You can use dd to write a file to a device (e.g. tape).
>
> Kris
>

I thought so too, but it doesn't work. When I issue

   dd if=var-20050516 of=/dev/nsa0

I get the following error:

dd: /dev/nsa0: Invalid argument
1+0 records in
0+0 records out
0 bytes transferred in 0.000786 secs (0 bytes/sec)

Since 'dump' works with /dev/nsa0 I am not sure what the
problem is.

Viren