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 Post subject: AO related query
PostPosted: Wed Aug 21, 2019 1:43 am 

Joined: Mon Jul 03, 2017 9:05 pm
Posts: 20
Hi Team,

In our environment AO is in suspended state for more than 2 years. We have all the default AO's like cost, balanced and Performance running earlier and one fine day it was stopped as per the request from client.

Many VV's are residing in Balanced AO and i can see that in that itself majority of the data are residing in NL and FC10K. Very less data resides in SSD. I can see that NL and FC10K is oversubscribed. NL is oversubscribed upto more than 3 times the IO it can handle. FC10K also getting hitting with IO double of it can handle. Other disk types in the 3par are fine like FC15k and SSD.

Now, because of this we are facing performance issue in the array. So i have suggested client for enabling AO. But client was suggesting to manually moving all the content of NL to higher tiers.

We cannot move it to FC10K as it is already oversubscribed. Also not to SSD as it is costly and client will not invest more in procuring more SSD's.

So, i insist on enabling AO, so that it will manage the data movement according to the IOPs to different disk types and it should resolve the latency issue.

But one issue is that in between once i tried enabling it and what i noitced is that the disk utilization of SSD which was already above 90% touched 110%, not sure how it can cross 100% and go to 110%.

Also in the AO rules , our IO monitoring happens during BAU hours and data movement happens after midnight. So not sure when i enabled AO at the morning time , how the disk utilization % touched 110% and that within 5 secs time. So there was no actual data movement happens as in 5 sec it will not be possible to fill data that fast.

Also as i noticed it touched 110% , i disabled the AO and within 5 sec all the disk types utilization went down to previous state.

So would like to know that this behavior is normal? Now if i enable again AO after a gap of nearly 2 years what are all precautions i have to take that no unforeseen issues occur.

TIA for your help.


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 Post subject: Re: AO related query
PostPosted: Wed Aug 21, 2019 6:56 am 

Joined: Mon Sep 21, 2015 2:11 pm
Posts: 933
Location: Europe
From what I read, you can't make it worse with AO ... You might not fix it, but it shouldn't become any worse.

As for 110%, where are you seeing this?

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 Post subject: Re: AO related query
PostPosted: Wed Aug 21, 2019 7:07 am 

Joined: Mon Jul 03, 2017 9:05 pm
Posts: 20
MammaGutt wrote:
From what I read, you can't make it worse with AO ... You might not fix it, but it shouldn't become any worse.

As for 110%, where are you seeing this?


In IMC, it is showing in the disk utilization, % utilized by each disk types


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 Post subject: Re: AO related query
PostPosted: Wed Aug 21, 2019 8:38 am 

Joined: Mon Sep 21, 2015 2:11 pm
Posts: 933
Location: Europe
Never trust IMC.... It refreshes about once every decade and hasn't been tested or qualified since 3.2.1 GA or something.... Could possibly even be 3.1.3 ...

If you get the same display in CLI or SSMC I would worry.

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 Post subject: Re: AO related query
PostPosted: Wed Aug 21, 2019 9:54 pm 

Joined: Mon Jul 03, 2017 9:05 pm
Posts: 20
MammaGutt wrote:
Never trust IMC.... It refreshes about once every decade and hasn't been tested or qualified since 3.2.1 GA or something.... Could possibly even be 3.1.3 ...

If you get the same display in CLI or SSMC I would worry.


we are on 3.2.2 MU4 and our arrays are 7400 series.. SSMC also shows same utilization...


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 Post subject: Re: AO related query
PostPosted: Thu Aug 22, 2019 4:47 am 

Joined: Mon Sep 21, 2015 2:11 pm
Posts: 933
Location: Europe
nishanth wrote:
MammaGutt wrote:
Never trust IMC.... It refreshes about once every decade and hasn't been tested or qualified since 3.2.1 GA or something.... Could possibly even be 3.1.3 ...

If you get the same display in CLI or SSMC I would worry.


we are on 3.2.2 MU4 and our arrays are 7400 series.. SSMC also shows same utilization...


What about showpd -c in CLI?

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 Post subject: Re: AO related query
PostPosted: Sun Aug 25, 2019 8:10 pm 

Joined: Mon Jul 03, 2017 9:05 pm
Posts: 20
MammaGutt wrote:
nishanth wrote:
MammaGutt wrote:
Never trust IMC.... It refreshes about once every decade and hasn't been tested or qualified since 3.2.1 GA or something.... Could possibly even be 3.1.3 ...

If you get the same display in CLI or SSMC I would worry.


we are on 3.2.2 MU4 and our arrays are 7400 series.. SSMC also shows same utilization...


What about showpd -c in CLI?


Yes, it is touching 110% in seconds while enabling AO and if we suspend it , within seconds it is coming back to normal disk utilization % as well.


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 Post subject: Re: AO related query
PostPosted: Mon Aug 26, 2019 4:14 am 

Joined: Mon Sep 21, 2015 2:11 pm
Posts: 933
Location: Europe
nishanth wrote:
MammaGutt wrote:
nishanth wrote:
we are on 3.2.2 MU4 and our arrays are 7400 series.. SSMC also shows same utilization...


What about showpd -c in CLI?


Yes, it is touching 110% in seconds while enabling AO and if we suspend it , within seconds it is coming back to normal disk utilization % as well.


I would log a case with HPE ... Sounds like a bug when even CLI states it.

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