bad disk does not change mode from srdf/a to acp_disk. it need to be set explicitly.

with srdf/a session consistence enabled you should be able to sync/split.

Could you explain a little more on on srdf setup

When a single pair in a SRDF/A session have issues, the default behaviour of SRDF/A is to "tolerate" a different state for the affected pair. This obviously means that R2 devices won't be consistent since at least an R2 have a different PIT image of your R1 devices.

If you enable consistency, all devices in the same session will drop to Suspended in case of issues with any drive, thus preserving consistency of R2 devices (since all R2 devices have same PIT image).

Santhosh "symrdf enable" is a "lock" you put on your RDFG to preserve consistency of R2 image. While the lock is closed (while consistency is enabled), you can't change the group. And in case a single pair have issues, the whole group drops the session (so that your R2 image is consistent).

you mean it is mandatory to "symrdf disable" before the mode switches operations (like async,acp_disk)

If you "enabled" consistency on your RDFG, you have to disable it before changing mode and/or changing pairs ..

This is what i was experiencing.While the tolerance mode is on,I couldn't perform any SRDF operations until i disable it.

Stefano,Is it better to leave tolerance mode to off so that it doesn't drop the SRDF for any small disruption?

My wording is confusing you ...

1) the default behaviour is to leave tolerance enabled
When you switch mode to "async", you have tolerance enabled. Thus if you have issues on a drive, you have an inconsistent image on the R2 devices.

2) when you disable tolerance (when you enable consistency) you "lock" the whole RDFG.
In case a single pair have issues all pairs drop to Suspend.

The correct behaviour is with TOLERANCE DISABLED (CONSISTENCY ENABLED) since you "pay" SRDF to give you a consistent R2 image and not a fuzzy one

It was consfusing but i got it.So ideally we will leave Tolerance Disabled(Consistency Enabled).But When Split/Suspend/Fail-over needs to be achevied,Disable the Consitency or is there any option?

Also,What would happen if one of the link fails(2-redudant links) while tolerance was off?

Missed this part

Message was edited by:
srichev

Yep you got it .. you have always to keep your RDF/A sessions ENABLED...
If you have to suspend/split/failover you have to disable consistency.
I guess Symcli manuals also explain how to use various "-force" options with symrdf in case you have an issue and can't disable consistency. However the right thing to do is to disable consistency and issue "regular" commands.

-s-