> > DDS-2 should give 500kB/s uncompressed speed. compressed differs frm data
> > type
> 
> Oh yes, I was thinking of the compressed rate.  I can't find the numbers
> anywhere in HP documentation (argh, I _want_ technical information!!).

compressed speed depends of data and raraely is more than 2xuncompressed.
 
> Anyway, I couldn't fit more than 3.2 GB on a 4 GB tape (uncompressed
> capacity), so something was (is?) wrong.

mt compress 1

> On Sun, Apr 01, 2001 at 08:11:36PM +0200, wojtek@wojtek.from.pl wrote:
> > try doing it without "buffer"
> > 
> > tar cvf - <data to backup>|ssh host "dd bs=32k of=/dev/rst0"
> 
> Does dd do double buffering?  If not, the tape would stop streaming if
> there was a slight delay in network or on the other machine?  I wanted
> to use buffer because it does double buffering and simultaneous read/write
> to the buffer.

tape drive has it's own buffer (mine about 1MB)
 
> On Sun, Apr 01, 2001 at 09:55:18PM +0200, Bernd Sieker wrote:
> > > what blocks does "buffer" program use?
> > > 
> > > try setting blocks to 0 (mt setblk 0) and set 32kB output block size in
> > > "buffer". i do not use buffer no i don't know what's the options
> > > 
> > 
> > Also try to use the "buffer" program on both computers, not only on
> > the one with the tape drive.
> 
> I increased the block size in buffer to 32k and things got better.
> 
> I'm not sure if using buffer at the other end would help - in this case,
> I'm copying a bunch of large (> 100 MB each) .tgz files to tape - reading
> them off the disk fast enough is not a problem.  I understand that another
> buffer could make a huge difference when archiving lots of small files.
> 
> Is it normal that every now and then (every 3-4 minutes or so) the DAT drive
> does something odd and stops receiving data for a while?  I'm monitoring
> the network traffic with netstat -w 10 and the numbers drop every now and
> then.  Maybe I should install my old drive and see if it does the same..
> but it started eating my tapes :-I
> 
> Thanks to all.
> 
>   -jm
> 

-----------------------------------------------
UNIX *is* user friendly.
It is just a bit selective about his friends.