Legacy HDS Forums

USP capacity and HSSM

Discussion created by Legacy HDS Forums on Jan 30, 2007
Latest reply on Mar 5, 2007 by Legacy HDS Forums

Originally posted by: stephen2615



Greetings,

Perhaps someone could explain what I see as it has often puzzled me no end. It was never explained even during my HDS training.

When I look at Storage Navigator in the Licence Key, I see a total storage size in TB which has to be raw sizes. It is roughly what I expect considering the number and size of the disks we have in the USP. I also assume that that figure includes any external raw storage virtualised into the USP.

Now when I look at Device Information, I see different information.

I see Open Volume figures and Mainframe figures and also external storage figures but all these added together comes well short of the total raw storage. So I would expect that the LDEV capacity is actually the usable disks. So if every disk is in a 7D+1P parity group, that would mean we loose about one eighth of the capacity plus the spare disks. This figure is still well short. It is a considerable amount that does not seem to be visible.

When I look at HSSMs report on the USP, the figure are confusing. Could someone explain what the following actually mean?

Total Internal.

That figure is basically what I would expect to have usable in the USP but it is nothing like what is in the Storage Navigator Device Information.

Actually, a full description of all the fields in the report "Storage_Capacity_by_Vendor_Over_Time" would be most helpful.

Device Manager gives nearly the same information as HSSM so I think they may use each other.

It is very hard to do capacity management when you don't know just how much storage you have. I am talking about significant differences between the two "capacity" systems.

Cheers

Stephen

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