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What algorithm does ViPR use for port allocation for Symmetrix provisioning?

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ViPR leverages a lot of EMC storage knowledge; just wondering what's going on here between ViPR and VMAX.

Thank you.

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Re: What algorithm does ViPR use for port allocation for Symmetrix provisioning?

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Hi Mark,

For VMAX, ViPR uses a simplistic port usage metric, which is the count of the number of Initiators in the ViPR system using that port. Once all the redundancy considerations have been met, the port with the lowest usage metric is picked from the remaining candidate list. ViPR uses masking views/port as one of the parameter for choosing port for storage allocation.

Also the following is how it works for VPLEX. The storage ports allocator also considers whether directors are A-side or B-side directors. It will allocate ports from alternating director sets (the A or B set) if possible. This is advantageous in certain VPLEX rolling upgrade scenarios.


Thanks,

Dee

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Re: What algorithm does ViPR use for port allocation for Symmetrix provisioning?

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Hi Mark,

For VMAX, ViPR uses a simplistic port usage metric, which is the count of the number of Initiators in the ViPR system using that port. Once all the redundancy considerations have been met, the port with the lowest usage metric is picked from the remaining candidate list. ViPR uses masking views/port as one of the parameter for choosing port for storage allocation.

Also the following is how it works for VPLEX. The storage ports allocator also considers whether directors are A-side or B-side directors. It will allocate ports from alternating director sets (the A or B set) if possible. This is advantageous in certain VPLEX rolling upgrade scenarios.


Thanks,

Dee

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Re: What algorithm does ViPR use for port allocation for Symmetrix provisioning?

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Port allocation on VMAX is done in 2 steps.
First, number of ports needed per network is decided based on Minimum Paths, Paths Per Initiator and Max Paths (as defined in Virtual Pool). Number of ports are balanced across eligible (that contains host initiators) networks.

Second, ports are selected from each network as shown below:
Eligible ports are decided by applying filters(removing already used ones) on available ports in the following order:
- already allocated ports
- rule17 (applied only to VMAX with directors that can be summed to 17): picks only ports from directors that can be summed to 17
- directory type
- engine
- director
- ports connected to different SAN switches
From these eligible ports a port is chosen with minimum usage (calculated using initiator mappings)
Note: filter is only applied if the remaining set is not empty and it will recycle allocated ones resulting in round robin fashion of selecting ports.