As always, performance issues can be prefaced with "it depends on your
circumtances but"
to which I will add, the cpu you have is slow enough that it isn't likely to
be able to keep dozens of drives seeking and transferring away all at once.
I think you would be fine with 9 or 18gb drives for most applications,
especially if you add some more memory, which can really improve
performance.
If you are running a 20 gigabyte data set being randomly accessed by hordes
of users all at the same time, having lots of smaller drives, spread over
a number of controllers, would be best.
You didn't say how your system is configured (home many SCSI channels, and
what is on each, etc.) Assuming you have 3 channels (the built-in one and 2
add ons) then spreading the discs over all the controllers. Since the system
disc (ldev 1) gets hit harder than most, I would put the least amount of
other drives on its controller (typically just the other internal drives.)
I would put the external drives on their own controller. Used SCSI
interfaces
are only $500 or so, so there is no good reason not to have the extra
expansions slots used for two more. (You have to add an expansion option
to get even more slots inside the chassis, but can get a total of 4 full
length slots suitable for the HP 16 bit FW SCSI card.
Once you get too much disc, you will want a faster backup system. However,
DLT7000 or 8000 drives need a dedicated SCSI controller. Backing up to a DLT
7000,
I see speeds in the 4mb/second range, with all our drives on a single
controller.
On another, faster machine, with drives spread over 3 controllers, I see
more like 6mb/sec on a full system backup (this is with drive compression
on,
and the INTER option on, etc.)
At this point you really need to look into the 2 slot I/O expansion,
or perhaps moving to a new N series with much better I/O.
-----Original Message-----
From: Paul Thompson [mailto:[log in to unmask]]
Sent: Tuesday, February 27, 2001 4:59 AM
To: [log in to unmask]
Subject: [HP3000-L] Disk Size/Performance
Hi
Just a quick question - we have a HP3000 939-020 and are looking to increase
the number of non_raid disks we have. We currently have 4.3Gb disks
installed but are considering buying 9 or 18Gb disks. I was mainly wanting
to know if there will be any issues regarding performance, etc or would we
be better sticking to 4.3Gb disks?
TIA
Paul Thomspon
Spark Response
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