AaronNortonEMC
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ProSphere 2.0.1.0 Subscription and VMAX with FAST-VP

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I have a ProSphere environment that has discovered multiple VMAX arrays. Each VMAX array has 3 Thin Pools and all are using FAST-VP. I upgraded ProSphere to 2.0.1.0 because of the ability to see Subscription % for the VMAX arrays. I understand from the release notes that I will still not see the % Subscribed for the individual pools but I will be able to see it on the Block Capacity reports for the arrays as a whole. I believe the reasoning I read was because with FAST-VP a LUN is not really subscribed to 1 individual pool but instead to multiple pools.

That all makes pretty good sense to me but the numbers I see in ProSphere don't seem to match my understanding. I would expect the numbers I see in ProSphere to match the numbers I see when I run the command "symcfg list -pool -thin -detail -gb". When I run that command there is a line right before the legend that says "Total GBs". This line adds up the total available, usable, free, used from all 3 thin pools and then calculates the %Full and %Subscribed based on those numbers.

One particular array now has all LUN's bound to the FC pool. The symcfg command above reports the "Total" % Subscribed for the array to be 78%. However when I look in ProSphere it shows 199.96% Pool Subscribed when I view the Block Capacity report.

I have looked through a lot of numbers and I believe I have figured out how the application comes up with that number. The command "symcfg show -pool POOL_NAME -thin -detail -gb" will show the number of GBs total size for LUN's that are either bound to the pool or devices that are bound to other pools but consuming some number of tracks in the current pool. ProSphere seems to be adding that number from every pool together and using that with the total size of the array to come up with a % Subscribed.

The problem with that approach is it could essentially double your subscription rate when you are talking about the array as a whole. If I have a LUN that is bound to the FC pool and FAST-VP has moved some extents of that LUN into each of the 3 pools then the total size of that LUN will be added for each pool. That to me is not an accurate subscription % because that LUN could never grow that large.

Has anyone else noticed this? Is my thinking correct or am I not understanding the intent of the % Subscribed numbers shown in ProSphere?

Sorry for the long post.

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AaronNortonEMC
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Re: ProSphere 2.0.1.0 Subscription and VMAX with FAST-VP

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It was fixed in the recent 2.0.1.3 release. The subscription numbers now appear much more accurate.

Aaron

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Craig_Stewart
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Re: ProSphere 2.0.1.0 Subscription and VMAX with FAST-VP

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Did you ever get to the bottom of this Aaron?

I'm currently looking at this sort of thing from a Unisphere for VMAX perspective and trying to get numbers for the aggregate capacities across the 3 tiers.  Be keen to understand if you got to the bottom of how it is operating.

Cheers


Craig Stewart

Senior Systems Engineer

UK/I

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AaronNortonEMC
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Re: ProSphere 2.0.1.0 Subscription and VMAX with FAST-VP

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It was fixed in the recent 2.0.1.3 release. The subscription numbers now appear much more accurate.

Aaron

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