Performance problems (solved)

Joerg Schilling was, as one may expect, right: I must read more careful the man pages. 
(as excuse: there are so many man pages and it worked for years).

I now use as commandline for the backup:

    /opt/schily/bin/star VOLHDR="rmnd-ux4.rmnd.in.aoc:20050905-02:30"  
    -c -v -sparse   artype=exustar -acl -xattr  -fifo bs=1M fs=144m
    -time -fifostats   f=/dev/st0 ./home/... ./home/.. etc.

The option fs=144m  is important for the speed of the backup. With the Sony AIT SDX-
700C I managed to get a speed of +/- 20.000 kBbytes/sec.  The servers has 1 Gb of 
memory. The streamer has a buffer of 18 Mb.  I found hardly any speed difference 
between fs=90M and fs=256M. Only the fifo statistics were different. 

Some statistics:
    /opt/schily/bin/star: fifo had 1836497 puts 76736 gets.
    /opt/schily/bin/star: fifo was 115 times empty and 572 times full.
    /opt/schily/bin/star: fifo held 150994944 bytes max, size was 150994944 
    bytes
    /opt/schily/bin/star: 76736 blocks + 0 bytes (total of 80463527936 bytes = 
    78577664.00k).
    /opt/schily/bin/star: Total time 8432.992sec (9317 kBytes/sec)

We maintain 4 identical servers on 4 different locations. The overal backup speed is now 
between 6.000 kBytes and11.000 kBytes/sec. I did not have time to find out why 
20.000 kBytes/sec is possible 

Furthermore I found that xfsdump is the fastest dump utility. Faster then star. But very 
specific: only XFS filesystems.

Thanks for all the comments. 

Met vriendelijke groet/Regards,
Ruud Baart

Prompt, Kerkstraat 173
5261 CW Vught, Netherlands
Tel: +31 73 6567041
http://www.prompt.nl