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 Post subject: Default paramerters
PostPosted: Tue Sep 29, 2020 4:25 pm 

Joined: Thu Apr 28, 2016 1:29 pm
Posts: 24
Hi all,
I realize in the latest versions of SSMC, you don`t set certain things anymore that we were given option when we used IMC.
For example when you create CPG, it doesn`t show you "step size" "chunklet location" anymore.
Array determines itself. But you can still set them via CLI.
Do you guys bother setting them anymore? Does it matter on a system with 480drives?


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 Post subject: Re: Default paramerters
PostPosted: Tue Sep 29, 2020 11:52 pm 

Joined: Mon Sep 21, 2015 2:11 pm
Posts: 1158
Location: Europe
bbarbaros wrote:
Hi all,
I realize in the latest versions of SSMC, you don`t set certain things anymore that we were given option when we used IMC.
For example when you create CPG, it doesn`t show you "step size" "chunklet location" anymore.
Array determines itself. But you can still set them via CLI.
Do you guys bother setting them anymore? Does it matter on a system with 480drives?


Did you ever change it from the default when you could? :)

The type of system doesn't matter for those system, just the load. Increased set size is good for large IO sequential IO, but will create hot spot with smaller/normal and/or random IO.

Chunklet location was a really weird one. In the outer part of the platter you would read more blocks per rotation. So do you want that minor performance increase on the first or last bit of data you write... probably an interessting parameter in 2007, today you just add flash and get a lot more performance for close to nothing.

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 Post subject: Re: Default paramerters
PostPosted: Wed Sep 30, 2020 10:38 am 

Joined: Thu Apr 28, 2016 1:29 pm
Posts: 24
MammaGutt wrote:
Did you ever change it from the default when you could? :)

The type of system doesn't matter for those system, just the load. Increased set size is good for large IO sequential IO, but will create hot spot with smaller/normal and/or random IO.

Chunklet location was a really weird one. In the outer part of the platter you would read more blocks per rotation. So do you want that minor performance increase on the first or last bit of data you write... probably an interessting parameter in 2007, today you just add flash and get a lot more performance for close to nothing.


It`s been a while I haven`t created new CPGs...I realized it now after we doubled the size in one of our arrays and now I`m gonna rebalance the system into the new CPGs...For example Old CPG step size is 64KiB but now HPe suggest 128KiB...I oculdn`t find any document towards pros or cons of old settings...So I`ll just trust 3PAR and keep things default


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 Post subject: Re: Default paramerters
PostPosted: Thu Oct 01, 2020 2:17 am 

Joined: Mon Sep 21, 2015 2:11 pm
Posts: 1158
Location: Europe
bbarbaros wrote:
MammaGutt wrote:
Did you ever change it from the default when you could? :)

The type of system doesn't matter for those system, just the load. Increased set size is good for large IO sequential IO, but will create hot spot with smaller/normal and/or random IO.

Chunklet location was a really weird one. In the outer part of the platter you would read more blocks per rotation. So do you want that minor performance increase on the first or last bit of data you write... probably an interessting parameter in 2007, today you just add flash and get a lot more performance for close to nothing.


It`s been a while I haven`t created new CPGs...I realized it now after we doubled the size in one of our arrays and now I`m gonna rebalance the system into the new CPGs...For example Old CPG step size is 64KiB but now HPe suggest 128KiB...I oculdn`t find any document towards pros or cons of old settings...So I`ll just trust 3PAR and keep things default


Just checking, you do know there is a command called tunesys that will rebalance everything for you? If you want to change any parameters on the CPG you can do that before you start tunesys and it will fix that for you as well ... in one single input from you :)

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 Post subject: Re: Default paramerters
PostPosted: Sat Oct 03, 2020 4:18 pm 

Joined: Thu Apr 28, 2016 1:29 pm
Posts: 24
MammaGutt wrote:
Just checking, you do know there is a command called tunesys that will rebalance everything for you? If you want to change any parameters on the CPG you can do that before you start tunesys and it will fix that for you as well ... in one single input from you :)


Yep, I know all that. You can change anything, still available in CLI. My question was, if I need to be even bothered with it if they are not given to you as an option when you do stuff via SSMC?


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 Post subject: Re: Default paramerters
PostPosted: Sun Oct 04, 2020 1:03 am 

Joined: Mon Sep 21, 2015 2:11 pm
Posts: 1158
Location: Europe
bbarbaros wrote:
MammaGutt wrote:
Just checking, you do know there is a command called tunesys that will rebalance everything for you? If you want to change any parameters on the CPG you can do that before you start tunesys and it will fix that for you as well ... in one single input from you :)


Yep, I know all that. You can change anything, still available in CLI. My question was, if I need to be even bothered with it if they are not given to you as an option when you do stuff via SSMC?


The simple answer would be "as a best practice don't bother unless another relevant best practice states otherwise". There has always been a lot of parameters only available in CLI that are there for corner cases. I know as an example thar both dedicated Exchange and SAP whitepapers go outside the best practice but unleds you have a 3PAR dedicated to Exchange or huge SAP installation I would care.

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 Post subject: Re: Default paramerters
PostPosted: Sat Oct 24, 2020 2:13 pm 
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Joined: Tue Oct 07, 2014 8:34 am
Posts: 192
The way is to simplify the GUI for the Customer.
Take a look at the Primera GUI, everything should be as simple as can and Self Serviced.


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