Francisco Jose Montilla wrote:
>
> On Fri, 22 Oct 1999, Thomas Seidel wrote:
>
> Hi,
>
> > Here is the output of df -k:
> > Filesystem 1024-blocks Used Available Capacity Mounted on
> > /dev/md0 5916736 811879 4798422 14% /
> > /dev/md1 3106031 41673 2903712 1% /var
> > /dev/sda1 83561123 11922926 67127549 15% /data
> >
> > To backup I use:
> > mt -f /dev/nst0 rewind
> > mf -f /dev/nst0 datcompression 2
> > dump 0uBf 96000000 /dev/nst0 /
> > dump 0uBf 96000000 /dev/nst0 /var
> > dump 0uBf 96000000 /dev/nst0 /data
> >
> > The third dump stops at 97% with "end of tape". The sum of the used blocks of
> > the filesystems is about 12 GB.
>
> That's right. It seems that you aren't really setting compression
> on, the math is clear :)
>
> I'd check the jumpers to see if the unit allows hardware
> compression to be set by software. Check either hp.com for this or the
> unit documentation. Once you're sure that the unit allows it, use mt-dds
> to set it. I found that mt-st don't do it properly...
from the mt manpage... if you set the count to 1 after setting the
compression it should give you a status of the compression...
# mt -f /dev/nst0 datcompression 2
# mt -f /dev/nst0 datcompression 1
datcompression
(some SCSI-2 DAT tapes) Inquire or set the compres
sion status (on/off). If the count is one the com
pression status is printed. If the count is zero,
compression is disabled. Otherwise, compression is
enabled. The command uses the SCSI ioctl to read
and write the Data Compression Characteristics mode
page (15). ONLY ROOT CAN USE THIS COMMAND.
