SRDF/Metro: Array failure - disable witness?

Question

Hi there,

we have been looking for more detailed information what actually happens to the Bias if one VMAX3 in a SRDF/Metro configuration with a witness fails.

Will the Bias be moved to the surviving VMAX3?

What happen if the witness also fails after one VMAX3 failed?

Say during the time the failed VMAX3 get's fixed and during this period the RDF links towards the witness will disconnect.

Can someone provide so more information about the behavior of the surviving array and what happen to the actual device.

Any ideas, hints, explanations are appreciated

Tom

vPert · Answer

Hi there,

I work for a EMC Partner and the questions came up because we do DR planning for one of our customers.

Sorry for saying so, but this was not the question. We are well aware on the failure scenarios mentioned in the Technical Note “EMC VMAX3 SRDF/Metro Overview and Best Practices” and also in the SRDF CLI User Guide.

The things we are not sure about is, what happen if say S1 is down for a longer period of time (eg. DC destroyed during natural disaster and needs to be rebuild from ground up) . S2 and the witness array are up and running. Then the witness or the communication to the witness fails – what will happen on the S2.

Reason for asking: we need to define the steps which need to be performed to make sure the S2 survives a witness failure without disrupting production.

Q1: do we need to move Bias (swap identity) for all volumes to S2 or has this been done by the witness already?

Q2: how can the witness be disabled without disrupting production?

Q3: is there a procedure available how to handle such a case?

Thanks

Tom

Von: deepak_vokaliga

Gesendet: Donnerstag, 3. März 2016 20:05

An: Tom Schmuki

Betreff: Re: - SRDF/Metro: Array failure - disable witness?

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SRDF/Metro: Array failure - disable witness?

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SRDF/Metro: Array failure - disable witness?

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