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Re: 70GB load source and 5 other drives



fixed

"It Depends" :-)

If this is only for a couple users doing testing and development for example you may find this config provides acceptable performance. It WILL IPL more slowly as that is a very intense period of I/O and PTFs will be more slow to apply but those are not daily things.

If you are running any production things here and you see that one drive's percent busy going to 100 frequently then yes you will want to redo this. Unfortunately the ONLY way to make the load source drive smaller is with Save and Restore. You cannot copy the load source using service tools to a smaller drive.

- Larry "DrFranken" Bolhuis

www.frankeni.com
www.iDevCloud.com
www.iInTheCloud.com

On 4/25/2014 9:31 AM, Steinmetz, Paul wrote:

Larry,

Thanks for that explanation. The virtual IO q then is the bottleneck.
So the below is not good, 1 200 gb storage space which results in 1 drive.
So I should redo my config?
Is it really necessary?.
1st storage space 80 gb
2 thru 6 - ??
Work with Disk Status PENCOR08
04/25/14 09:15:49
Elapsed time: 00:00:00

Size % I/O Request Read Write Read Write %
Unit Type (M) Used Rqs Size (K) Rqs Rqs (K) (K) Busy
1 6B22 186417 30.6 .0 .0 .0 .0 .0 .0 0

Paul

-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of DrFranken
Sent: Friday, April 25, 2014 9:17 AM
To: Midrange Systems Technical Discussion
Subject: Re: 70GB load source and 5 other drives

You WILL want more than one drive for the guest if you do any significant I/O. It's NOT for the benefit of the host as you are correct that workload on the host is spread across all available drives there. The rub is that on the client you now have ALL your I/O through one queue. That queue has limited depth. So while the host partition can handle lots of I/O the guest can only get a limited amount into the queue for the host to do. IBM i has ALWAYS wanted arms, arms are good, and it's true even when they are virtual. The minimum recommended for good performance is 6 arms which is then 6 storage spaces on the host.

- Larry "DrFranken" Bolhuis

www.frankeni.com
www.iDevCloud.com
www.iInTheCloud.com

On 4/25/2014 9:11 AM, Steinmetz, Paul wrote:

Rob,

I only created one storage space.
If one storage space is spread across all host drives, why would need more than 1 storage space.
I'm not seeing where additional storage spaces will gain performance.

My guest LPAR is only used for creating DSLO images and/or testing the install of a DSLO image.

My guest LPAR actually IPLs quicker than the hosted LPAR.
I would think it would be the opposite.

Paul

-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of rob@xxxxxxxxx
Sent: Friday, April 25, 2014 8:49 AM
To: Midrange Systems Technical Discussion
Subject: RE: 70GB load source and 5 other drives

Replace "drives" by "storage spaces".
You should not just create one big storage space for the guest.
You should create 6 or more for performance reasons.
Yes, when you do a CRTNWSSTG it will spread that over all the drives in the ASP you create it.
However, the guest still needs 6 'logical units' or LUNs as they talk about it in the SAN world.
You CAN do just 1. I have. Those lpars are also very slow.
Where do you see that your bottleneck is the lack of LUNs in performance tools? I haven't a clue. I'm just standing on the shoulders of giants.

Ok?


Rob Berendt
--
IBM Certified System Administrator - IBM i 6.1 Group Dekko Dept 1600 Mail to: 2505 Dekko Drive
Garrett, IN 46738
Ship to: Dock 108
6928N 400E
Kendallville, IN 46755
http://www.dekko.com





From: "Steinmetz, Paul" <PSteinmetz@xxxxxxxxxx>
To: "'Midrange Systems Technical Discussion'"
<midrange-l@xxxxxxxxxxxx>
Date: 04/25/2014 08:39 AM
Subject: RE: 70GB load source and 5 other drives
Sent by: midrange-l-bounces@xxxxxxxxxxxx



Rob and Pete,

I'm confused. When you create a network server storage for a guest
LPAR, you only give it the size, no where do you tell it the number of drives.
If the host lpar has 8 drives, 8 will be used. If the host lpar has24
drives all 24 will be used. The guest storage will be evenly spread
across the number of drives of the host.
Is this correct?

Paul

-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx [
mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Pete Massiello -
ML
Sent: Friday, April 25, 2014 7:42 AM
To: Midrange Systems Technical Discussion
Subject: RE: 70GB load source and 5 other drives

Rob,

7.2 will need a 70GB load source, and that means
when you create it on the guest side you have to create it larger than
70 to get 70 on the hosted (or client) side. I have been using
approximately 79GB when I create them, and they have worked fine for
7.2. Then if the others are significantly smaller, I end allocations
on that drive to keep the I/Os more balanced on the spread of the I/Os
across the drives

Pete

--
Pete Massiello
iTech Solutions
http://www.itechsol.com
http://www.iInTheCloud.com





-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx [
mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of rob@xxxxxxxxx
Sent: Friday, April 25, 2014 7:18 AM
To: midrange-l@xxxxxxxxxxxx
Subject: 70GB load source and 5 other drives

I know that we covered this in a thread but I'm having a devil of a
time finding it. I found it alluded to in
http://archive.midrange.com/midrange-l/201401/msg00542.html

I have a guested system that is currently 279GB. And it's only 30%
utilized. I am doing an unload/reload and I want the 6 "luns".

I figured that I'd make the first one slightly over 70GB (like 75 or 80).
The reason being that it is a very hard halt with the next version of
OS, especially with virtualized disks, and IBM will publish the 'pad'
needed for VIOS, etc.

~300GB - 80GB = 220GB
220GB/(5drives/GB) = 44GB/Drive
So am I better off having 5 'luns' of 44GB each, or,
220GB/(35GB/drive)~=6 drives of 35GB each and having 6 drives of a
somewhat standard size?

Or refigure the whole thing since it's only 30% utilized.
279 * .3 = 81GB

80GB load source and how many of what size additional CRTNWSSTG spaces?
Cause you can see just how much wasted space I'll have with 6 drives
of 80GB.


Rob Berendt
--
IBM Certified System Administrator - IBM i 6.1 Group Dekko Dept 1600
Mail
to: 2505 Dekko Drive
Garrett, IN 46738
Ship to: Dock 108
6928N 400E
Kendallville, IN 46755
http://www.dekko.com

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