Jerlique Bahn wrote:

> It seems Amanda is going through the process of reading the whole tape and
> therefore will take several hours to restore about 10Mb in selected files?

Yes, it will do a read of the entire tape.  There is a config file option
called amrecover_do_fsf that if set to true will fsf your tape to the correct
spot if your drive supports it, which is much faster than a linear read.

> 
> My tape only seems to work at about 3 Mbps. The scsi disks it reads from
> (holding space) and writes to are capable of much more than that (U320, raid
> 5 array).

Best way to figure this out is to post the report that gets emailed
at the end of your run.  It shows dump and tape speeds for each DLE
and is very informative once you learn what you're looking for.
Two possibilities:
   You're bypassing the holding disk and going directly to tape due
to too small a holdingdisk or your reserve set too high to allow
fulls to go there.
   Contention on the disk, especially if it is also used for other
tasks, and compounded if inparallel is set very high.  RAID5 is often
not high-performance.  I've seen some that do well on a single read
or write, but seriously degrade with a few simultaneous  operations.
   Either way, if the dump can't feed the tape fast enough, the tape
keeps stopping and repositioning itself, vastly slowing your throughput
(and wearing out your drive and tape).  You might consider increasing
tapebufs in your config to buffer more data in memory.

Try dd-ing a large file from your disk to /dev/null, /dev/zero to
your disk, and /dev/zero to a blank tape, and see what the limits of
your particular hardware are.

Frank

> 
> JB
> 


-- 
Frank Smith                                      fsmith AT hoovers DOT com
Sr. Systems Administrator                       Voice: 512-374-4673
Hoover's Online                                   Fax: 512-374-4501