From: Howard E. Arnold (arnoldh@celerent.com)
Date: Fri Oct 18 2002 - 11:15:34 EDT
Thanks to everyone that replied.
Does anyone know if there are any diags or performance tools that can be run
from the San Appliance box? Something like dilx and vtdpy.
Following are the questions and the responses I got back.
> 1) I have read through most of the manuals and I can't seem to find
anything
> about the disk placement in the disk shelves. The shelves were configured
> with 8 disk in each starting in Bay location 4 going to 11. My question,
can
> I move the disks to start in Bay location 1 and go to 8 and would the
> performance be the same. I know with the EMA12000 and the split shelves
you
> would want to do something like this, but on these shelves I don't think
> this matters.
In EVA all disks share the same bus (like scsi bus in MA8000 in
single-channel disk shelves), only they are connected to two FC busses
at once. There's no "location-based" priorities in FibreChannel like
there is in Scsi. Furthermore, all disks have unique FC_AL IDs that are
the same regardless of their placement in the shelves.. :)
So it really doesn't matter at all where the disks are placed in the shelf.
> 2) This configuration came in with four San switches in the cab to connect
> the disk shelves and the controllers. Does it matter where the fiber
cables
> get plugged into?
Yup. AFAIK. Between the controllers and the shelves, they run on an
arbitrated
loop (at least on an HSV110). Don't move the connections as the guys who
stage it at compaq/hp usually know what they are doing.
> I have one other question concerning the configuration of Disk Groups
versus
> Virtual Disk folders. Does it make any sense to create multiple Disk
Groups
> or add all the disks into one disk group and then create virtual folders
for
> the different classification of disks. My though was to create one Disk
> Group for the OS disk and then one for the Oracle Database, but to have 8
36
> gig drives in the OS disk group seem to be a lot of over kill so I'm now
> thinking of creating one large disk group with all the disk and creating
> folders for the different classification of disk.
Disk group sets the maximum performance you can have for single unit. So
if you want to lessen performance, go ahead and create multiple disk
groups. Otherwise the only reason you would need to create separate disk
groups is - when application specifically requests that (i.e. that you
have disks "physically different".. :) The other reason is to separate
disks with different speed (i.e. 10k and 15k in case of EVA) if you want
to make sure that application would not share these disks.
Howard Arnold
Consultant Engineer
Email: arnoldh@celerent.com
Phone: (603)685-6060 ext 206
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