Building Disaster Tolerant Serviceguard Solutions Using Metrocluster with EMC SRDF
Building a Metrocluster Solution with EMC SRDF
Chapter 5324
R1/R2 Swapping using Metrocluster SRDF
The Metrocluster SRDF package can be configured to automatically do
R1/R2 swapping upon package failover. To enable R1/R2 swapping in the
package, set the environment variable AUTOSWAPR2 in the
<package_name>_srdf.env file to 1 or 2. Since the swap is done
automatically upon package start up, the Metrocluster SRDF software
will only do the swap if the Symmetrix frames and the SRDF links
between them are working properly, that is, the SRDF state of the device
group is in Synchronized state. If the failover and swap operations
succeed, the devices will have their personalities switched, and the data
replication will continue from the new R1 devices to the new R2 devices.
Prior to Metrocluster performing an R1/R2 swap, if the failover operation
fails, the package will not be automatically started. If the failover
operation succeeds, but R1/R2 swapping fails, then either the package is
automatically started or fails depending on the value of the environment
variable AUTOSWAPR2.
The environment variable AUTOSWAPR2 can be set to either “1” or “2”.
This will depend on whether the package needs to be started
automatically on R2, in case of R1/R2 swap failure.
If AUTOSWAPR2 is set to “1”, the package will fail to start if R1/R1
swapping fails. In this scenario it is necessary to start the package
manually by doing the swap operation. If preferred, this can be done at a
later time.
If AUTOSWAPR2 is set to “2”, the package is automatically started
regardless of a R1/R2 swap failure. In this scenario the data will not be
protected remotely.
NOTE When failing over a package with R1/R2 swapping, the package startup
time will be longer than without the swapping.
R1/R2 Swapping using Manual Procedures
It is also possible to do R1/R2 swapping manually. There are two
scenarios where manual swapping is supported by Metrocluster with
EMC SRDF.