[comp.sys.alliant] No. of IP and IO performance

eschle@forty2.physik.unizh.ch (Patrik Eschle) (10/29/90)

We are about to upgrade our system from Multibus (MB) to VME and will
have more disk then with *less* IP.

The current configuration is something like:

       MB IP   -- disk tray (2 disks)
                - exabyte / magtape
                - floppy
       MB IP   -- serial IO
       MB IP   -- disk tray (2 disks) 
                - ethernet
       VME IP  -- disk tray (2 disks)
                -  exabyte

This means one IP per disk tray.
In the new configuration there will 4 disk trays, but only 3 VME IP.

Although our local Alliant representative claims, that VME IP are
twice as fast as MB IP, a quick test shows that IO-performance is the
same for the VME and MB disks (about 350 kB/sec).

Question: What is your experience with IO-performance? 
          What's your IO configuration?


Thanks,
Patrik

(PS1: The quick test is :
         for write: 'time dd if=/dev/full of=bla bs=4k count=2500'
         for read:  'time dd if=bla of=/dev/null bs=4k count=2500'

 PS2: Has anybody an MX sendmail running on an Alliant?
)

-- 
Patrik Eschle, Physics Institute University of  Zuerich (Switzerland)
inet: eschle@physik.unizh.ch (bang: uunet!chx400!forty2!eschle)
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