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sanman999
1 Nickel

SRDF R1-R2 device attributes

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Hi,

What are the limitations of R2 device attributes, in reference to R1.

I have few  devices which are stripped 80gb( few 3 way meta and few no meta) devices. By new standard we are following 4 way stripped 100gb device.Usually SRDF we do same config as R1 device, but can I change the size and meta members for R2 device?? Please let me know if I can find any documentation on it. symm code is 5876

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PaulCork
2 Iron

Re: SRDF R1-R2 device attributes

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Below are the restrictions if you are looking at larger R2.

All swap and SRDF/Star operations are blocked.


If SYMAPI_RDF_CREATEPAIR_LARGER_R2 is set to DISABLE in the options file, all operations are blocked.

Data mirrored to a larger R2 device cannot be restored back to its R1 device.

Concatenated metadevices are not supported but striped metadevices are supported.

Usually we only see this used in migration activities because of the restrictions.

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4 Replies
christopher_ime
4 Beryllium

Re: SRDF R1-R2 device attributes

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Please consider moving this question as-is (no need to recreate) to the proper forum for maximum visibility.  Questions written to the users' own "Discussions" space don't get the same amount of attention and can go unanswered for a long time. 

You can do so by selecting "Move" under ACTIONS along the upper-right.  Then search for and select: "Symmetrix Support Forum".

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sauravrohilla
3 Argentium

Re: SRDF R1-R2 device attributes

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R2 size can be bigger but you wont be able to restore from a bigger R2 to smaller R1 in case of a disaster. If its okay with you then go for a larger R2 (you will need to enable a parameter in option file to do this).

Meta member number needs to be same.

regards,

Saurabh

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PaulCork
2 Iron

Re: SRDF R1-R2 device attributes

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SanMan999, if you are looking at expanding your RDF devices to 4 way meta then you can do this but you have to break the RDF relationship and do a full establish afterwards.

KB Article 6543 talks about online expansion of an RDF device.

You will need to repeat the process at the R2. R1, R2 must have the same number of meta members and config,(concat or striped) or you will get a meta mismatch when you try to pair.

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PaulCork
2 Iron

Re: SRDF R1-R2 device attributes

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Below are the restrictions if you are looking at larger R2.

All swap and SRDF/Star operations are blocked.


If SYMAPI_RDF_CREATEPAIR_LARGER_R2 is set to DISABLE in the options file, all operations are blocked.

Data mirrored to a larger R2 device cannot be restored back to its R1 device.

Concatenated metadevices are not supported but striped metadevices are supported.

Usually we only see this used in migration activities because of the restrictions.

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