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3PAR System Reporter Adaptive Optimization tier PD disk usage

 
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TimNNIT
Occasional Contributor

3PAR System Reporter Adaptive Optimization tier PD disk usage

I would like to know how to level the disk usage evenly between FC, FATA and SSD PD's. Currently the system uses 70% FC, and only 40% FATA and 40% SSD.

 

I thought changing the AO config could control this - but I don't see much effect when changing it. (I have waited several days after changing it)

 

How can I control the PD usage, if not via the AO configs?

6 REPLIES
Dennis Handly
Acclaimed Contributor

Re: 3PAR System Reporter Adaptive Optimization tier PD disk usage

>I would like to know how to level the disk usage evenly

 

What do you think "evenly" should be doing?

The whole purpose of AO is to move less frequently accessed data to to a lower tier like NL and more frequent to SSD.

TimNNIT
Occasional Contributor

Re: 3PAR System Reporter Adaptive Optimization tier PD disk usage

I would like to make rules which end up using an equal percentage of my FC, NL and SSD PD's.

 

I don't want to run out of FC PD's before NL's are also about to run out.

 

I thought I could control this by altering the AO config rules along the way, in order to keep having Performance, Balanced and Cost configurations with different configs.

 

Is that not possible?

Do I risk running out of FC space - or will AO by itself start using more NL when needed?

Sheldon Smith
Honored Contributor

Re: 3PAR System Reporter Adaptive Optimization tier PD disk usage

Sounds like you want to set your configuration mode to "Cost". It will weight things more toward the Tier-2 storage. You can set an Allocation Warning on the Tier-1 CPG, then AO will not use past that when moving things around.

 

Are you focusing AO measurement on the busier time of the system, or are you just looking at the last (24?) hours of activity? Typically over the course of a day, there's a window when the system is busier, and usually, that's a recurring trend over the course of a week. For example, a fairly common business environment is busiest 10a to 4p Monday thru Friday.

You may be including "slow" times which are skewing the movement calculations.

 

  1. "createaocfg" and "setaocfg" to set tiers and mode.
  2. "startao" to set report start and end times prior to the movement.
  3. "createsched" and "setsched" to set the schedule for the AO report.

Note: While I work for Hewlett Packard Enterprise, all of my comments (whether noted or not), are my own and are not any official representation of the company.
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Kenneth Walters
Occasional Contributor
Solution

Re: 3PAR System Reporter Adaptive Optimization tier PD disk usage

TimNNIT,

I do not believe that AO works the way you desire. It looks at the IO reporting period you defined and then, based on IO levels it sees in that window, combined with the MODE setting you selected, distributes the data across the three (or two) tiers that you have configured - usually SSD, FC, NL (what I use for prod) or FC and NL (what I use for dev/test). It is not trying to balance the disk utilization - rather, cost effectively distribute the data accross tiers taking into account performance characteristics.

 

Remember to make the the USR CPG for the VV the Tier 1 (not 0 or 2) CPG in the AO config. In this way your new data will be written to the mid-grade performance disk initially. If you sent it to NL first it could take a  few days to warm up. I would rather have it need to be cooled off than warmed up.

 

If there are VVs you know should always be in NL, then don't put them under AO in teh first place. Create or tune them to use NL. I force nothing to SSD, just let AO use that space.

 

To tweak AO you could also create multiple AO configurations - maybe a second one with just FC and NL and/or a different MODE. Place different VVs in each depeding on their need. Multiple AO configs with different tiering and different modes are the only way I know how to nudge AO in certain directions.

 

You do not have to worry about AO filling up a CPG from what I can tell. It takes CPG utilization into account and will not move regions to a full CPG.

 

There is a 3PAR best practices guide you should read if you have not. Note the cautions on setting limits and warnings as well as how to tier your AO configs.

 

How long are you allowing your AO config to run each evening? Is it finishing within the time limit? If not it may take a few days to get stuff moved around (check the detailed status). I have noticed that AO will run compactCPG now automatically but often does not. I am told that it won't run comapctCPG unless it thinks it can finish the command within the specified window. I have also been told that it has its own formula for when to run compactCPG and may decide it is not necessary (things need to be bad enough to cross some threshold).

 

Hope this helps, I don't pretend to be an expert so anyone else feel free to chime in and/or correct me.

Ken

 

 

 

 

TimNNIT
Occasional Contributor

Re: 3PAR System Reporter Adaptive Optimization tier PD disk usage

Thanks to both of you for answering me.

 

I read the Best Practices guide, but I just could not find the answer you just gave me.

 

I will relax and not worry about running out of FC for now. I suspected AO might work as you explain but did'nt quite believe it - thanks for the explaination.

 

:-)

Kenneth Walters
Occasional Contributor

Re: 3PAR System Reporter Adaptive Optimization tier PD disk usage

For what it is worth I had logged a call with HP 3PAR support and they confirmed that AO will not fill up a CPG. That tid-bit is not in the BP guide. You can limit how much space a CPG can use, but both allocation limits and warnings are not best practice for AO CPGs.