Problem splitting individual device using SRDF/A in async mode

Question

I have a number of devices configured as SRDF pairs. Currently all are in a single rdf group (RA group by ECC terms) and they are configured in async mode. I have the groups defined in distinct Device Groups. My plan is to be able to establish, split and failover these pairs on a Device Group basis. I tried to do a split on one Device Group and got the following error:
All the devices in the SRDF/A session must be managed together when the devices are in async mode

When in async mode, are we required to do these steps on the entire RA group at once? I have 17 different applications that need to be managed independently in terms of establish, split and failover, some of which are only going to be 1 or 2 devices. Am I going to have to have separate RA groups for each app?

xe2sdc · Accepted Answer

When in async mode, are we required to do these steps
on the entire RA group at once?

Yep.. When your RA group is working in async mode you must modify all devices at the same time. You can switch to sync, split or whatever you want. But only against ALL devices.

Am I going to have to have separate RA groups for each app?

Yep.. That's what I'd do

SKT2 · Answer

we do have multiple db/app in same DG.But each DG is with different RA groups. i think 'single rdf group' and 'distinct Device Groups' is creating confusion to me at the least..

Allen Ward · Answer

We have the same requirements you do, and the only solution we found was to create separate RA groups to match the DGs created for each application group. Fortunately we were able to group some apps together so we got our RA groups down to 7. I expect this to grow in the future, but there isn't a lot of choice in the matter.

xe2sdc · Answer

That's why recent codes raised max num of RDFG

Trouphaz · Answer

Thanks for the replies everyone. I guess I'll just split these devices across multiple RA groups.

pappc · Answer

Trouphaz,Keep in mind, the devices in an SRDF/A group are an implied Consistency Group. If a device or devices need to be take offline on the group, then the entire SRDF/A group must be set to Synchronous or Adaptive Copy Disk. Once Asynchronous is disabled on that group of devices, then the implied CG dissappears and the devices can be individually manipulated as required.Splitting your larger SRDF/A group into smaller groups by placing different DGs into their own groups will provide you many advantages in the future.If the devices are dynamic SRDF devices, and you have 5773, we have a new feature that allows you to move the devices into a different SRDF group, without forcing a full resync of the device pair (which was the case in earlier versions of Enginuity).I second Stefano's statement in saying having many smaller groups versus a few larger groups was one of the major motivational factors in greatly increasing the number of SRDF groups in recent years.Hope this helps,PSE Chris

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Problem splitting individual device using SRDF/A in async mode

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