10.1.9 Notes on using ETERNUS VS900 (virtualization switch)

Note the following points about the copying of virtual disks created in ETERNUS VS900, as explained in this section.

Copy function

EC/REC is the only copy function that can be used in ETERNUS VS900. For this reason, you should copy virtual disks using the synchronous-type replication of the replication function.
OPC functionality is not supported in ETERNUS VS900. Therefore, the backup function (that uses OPC for restore) cannot be used.

REC operation modes

Operation modes (Transfer mode, Recovery mode, Split mode) that can be used in ETERNUS VS900 are shown in the table below.

Table 10.4 Operation modes
Operation mode type	Operation mode that can be used
Transfer mode	Synchronous mode only
Recovery mode	Manual Recovery mode only
Split mode	Automatic Split mode only

Accordingly, the options for the operation mode that can be specified in swsrpstartsync (Synchronous processing start command) are different from the ETERNUS disk array.

Table 10.5 Transfer mode-related options
Option	ETERNUS disk array	ETERNUS VS900
-i (Consistency mode specified)	Operation is possible	Operation is not possible
-k (Stack mode specified)	Operation is possible	Operation is not possible
-y (Synchronous mode specified)	Operation is possible	Operation is possible (*)
None of -i, -k, or -y options specified	Operation is possible (in Asynchronous mode)	Operation is not possible

Table 10.6 Recovery mode-related options
Option	ETERNUS disk array	ETERNUS VS900
-g (Manual Recovery mode specified)	Operation is possible	Operation is possible (*)
-g option not specified	Operation is possible (in Automatic Recovery mode)	Operation is not possible

Table 10.7 Split mode-related options
Option	ETERNUS disk array	ETERNUS VS900
-a (Automatic Split mode specified)	Operation is possible	Operation is possible
-v (Manual Split mode specified)	Operation is possible	Operation is not possible
-a and -v options not specified	Operation is possible (in Automatic Split mode)	Operation is possible (in Automatic Split mode)

(*) In ETERNUS VS900, transfer mode and Recovery mode must be explicitly specified.

Consequently, specify the following format to start or restart REC when executing the replication start command. "-a" option can be omitted.

swsrpstartsync -y -a -g From-Volume-Name To-Volume-Name

The REC Operation modes that can be used in ETERNUS VS900 (Transfer mode, Recovery mode, Split mode) are fixed, however, therefore the operation mode cannot be modified using swsrpchsync (Synchronization mode change command).

EC/REC reversal

EC/REC reversal cannot be executed in ETERNUS VS900.

Displaying/modifying REC transfer buffer information

There is no REC transfer buffer in ETERNUS VS900. For this reason, the following commands cannot be executed for ETERNUS VS900: