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EVA5000 - disk levelling - controller use

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inex
Super Advisor

EVA5000 - disk levelling - controller use

We have an EVA5000. When adding more disk to a diskgroup and the system is doing levelling, will the EVA controllers be evenly used during this process?

-inex
4 REPLIES
Rick vonR
Advisor
Solution

Re: EVA5000 - disk levelling - controller use

As far as leveling goes, the controllers will balance the load but at a low priority with respect to I/O requests. If you have a large number of disks in the group, leveling could take quite some time.
If you are referring to incoming requests and controller load balancing, I/O requests coming into ports on the array is dictated by the hosts attached to the array. If you have multiple EVA ports assigned to a host, that host determines on which path to send the I/O either by which port got assigned first or by the MPIO driver if one is being used.
inex
Super Advisor

Re: EVA5000 - disk levelling - controller use

So lets say with no leveling, controller A has more i/o load than controller B. Then leveling starts, will this extra workload be split equally between controller A and B, or will controller B take more of this extra load, because it was less busy than controller A.

-inex
Rick vonR
Advisor

Re: EVA5000 - disk levelling - controller use

It is based on priorities. If controller B has less incoming requests it will handle more of the leveling. But again, leveling will take a back seat to I/O requests.
Johan Guldmyr
Honored Contributor

Re: EVA5000 - disk levelling - controller use

I thought the leveling was handled only be the owning controller of the vdisk that's being levelled?