Hi Marcy,
another option to be considered is to use SCSI devices under z/VM. You
might define a large SCSI LUN and address this - including multiple
paths to that device - like a DASD.
More information can be found in z/VM docu here:
http://publib.boulder.ibm.com/infocenter/zvm/v6r1/index.jsp?topic=/com.ibm.zvm.v610.hcpa5/edev.htm
And by the way, Linux also supports DASDs with more than 65520
cylinders, but this is afaik not yet supported in RHEL5.3 (These DASDs
are referred to as Model-A).
With kind regards
Thorsten Diehl
System Test Linux on System z
IBM Deutschland Research & Development GmbH
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Marcy Cortes schrieb am 04/16/2011 02:41 AM:
Oh, it's not so bad. It's only about 22 mod 54 per Terabyte.
Once it is out there and done (scripts are your friend) there's little
management to it.
We have one server with> than 110 mod 54.
What are you going to put on it Kyle? That may indicate whether the
performance will work for you w/o PAV.
Marcy
-----Original Message-----
From: Linux on 390 Port [mailto:[email protected]] On Behalf Of Mark Post
Sent: Friday, April 15, 2011 5:31 PM
To: [email protected]
Subject: Re: [LINUX-390] Largest DASD Volume to Use with RHEL 5.3 under z/VM 6.1
On 4/15/2011 at 08:21 PM, Kyle Stewart<[email protected]> wrote:
We are implementing another RHEL 5.3 under z/VM 6.1. The folks we are doing
this for would like 1-2TB of data. Can RHEL 5.3 use mod 54s?
Yes. Linux doesn't care about model numbers.
What are the
down sides?
Without the use of PAV, performance. z/VM can only start one I/O to a
subchannel at a time. The more data you have on one subchannel, the more you
might wait to get at it.
Would I be better off with mod 27s and if so, why? Thanks in
advance.
I would say that for that amount of data, you would be better off using SCSI
over FCP. Trying to build up very large file systems with DASD (and LVM) is a
pain to manage.
Mark Post
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