RE: Load Source Placement - Best Practices.

["Jim Oberholtzer" <midrangel@xxxxxxxxxxxxxxxxx>]

Kenneth, 

You can add far more reliable devices at the controller and storage device
layer to your list.
Also:  SSDs are so much faster for the type of workload like an IPL or other
OS layer operations.  Larry and I both posted some stats earlier.  Include
in those operations SAVE operations.  You could potentially cut the
restricted state save operations by quite a bit by A) moving the load source
to a controller that does not control the tape, and B) the speed of data
transfer is higher.  SAS will outrun SCSI most anytime.  

--
Jim Oberholtzer
Chief Technical Architect
Agile Technology Architects


-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of
Graap, Kenneth
Sent: Monday, March 16, 2015 1:43 PM
To: Midrange Systems Technical Discussion
Subject: RE: Load Source Placement - Best Practices.

> Are you using VIOS?
> Rob Berendt

Not at this time Rob. I'm just looking for some good reasons why it would be
advantageous to have load source on SSD. 

This is being driven due to a recent "incident" where one of the mirrored
load source disk located in the CEC, failed. No big deal usually... but the
second mirrored disk threw "noise" on the SCSI bus at the same time,
resulting in the system shutting down to protect the data. A system crash
occurred!

I want to move away from disk in the CEC. It will take some downtime to do
this and I'm looking for IBM or industry leader testimony that it is a good
idea to spend time and money on. This would make it easier to convince
management that the downtime is justified...

What can I say... They won't take my advice alone on this matter. Further
documentation, that it is the "best" thing to do would help my cause
considerably...

Maybe Sue Baker could give her opinion (???) 

My reasons: 

1.) Faster access from SSD through modern controller technology (5813 for
example)
2.) Faster access to load source could decrease the IPL time resulting in
less downtime.
3.) Dual path protection to the disk would provide better data protection.
4.) Moving away from the older MFIOP technology into newer SAS technology. 




Kenneth

 
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