From: microcom@tindrum.tng.oche.de (Wolfram Seidel)
Subject: Probs with Mylex Raid-Controller
Date: 1998/05/09
Message-ID: #1/1
Organization: Deja News - The Leader in Internet Discussion
Newsgroups: fido.novell


Hi,

I've got a Server system with the following configuration:

PPro 200, 512MB, Mylex DAC960 Raid Controller, 9 Disc-Drives (all Seagate
9GB). Currently they are configured as 3 Disc Packs with 3 drives each (RAID
5); OS is Netware 4.11


Problem #1:
When a drive is being rebuild (i have simulated this by disconnecting a drive
and reconnecting it later) the performance of the array drops to less than
1/30 of the original performance... this means, it is NOT possible to work
seriously with the server until the rebuild is finished. There exists a
parameter "Rebuild rate" which -according to the manual- sets the priority of
the rebuild process... but even on the  lowest setting "0" the speed of the
array is not acceptable.
However we have about 100 Users which need to work on the server... even if a
drive fails. (that is why we bought the raid system in the first place).

Is there any solution to this? I dont care if the rebuild process takes a long
time but the server must be usable during this time.


#2: Is it a good idea to configure the drives as we did? (3 packs with 3
drives each) or would other possibilities be better? Our first consideration
is security, not speed.  What about one pack with 8 drives (or two with 4) and
one as a standby drive? Would a different configuration perhaps help solving
my problem?


#3: If I down the server, disconnect one harddisk and switch it on again, the
Mylex BIOS refuses to configure the array... thus the system disk is
unavailable. I have to boot from floppy disk, start the Config-Program and
manually save the new configuration (one dead disk)... then reboot and then
the system drive will be available (in state "critical").
Is there no way to let the controller do this automatically?


If you know any answers to these questions....  I'd be happy


Yours
Wolfram

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