For Linux workload migrations, PlateSpin Migrate supports the use of freeze and thaw shell scripts to provide an additional means of control over your Linux block-level migration process.
Migrate executes these scripts during Linux workload migrations, at the beginning and end of block-level data transfer sessions. Specifically, they interject in the migration process in the following fashion:
First pass of all volumes without snapshots:
Regular (non-LVM) volumes
LVM without enough space to take a snapshot
Freeze script
Take snapshots
Second pass of all non-snapshot volumes
Thaw script
Transfer volume snapshots
You can use this capability to complement the automated daemon control feature provided through the user interface. See Services or Daemons to Stop before Replication or Cutover.
For example, you might want to use this feature to cause an application to flush its data to disk so that the workload remains in a more consistent state during migration.
To use the feature, do the following before setting up your migration job:
Create the following files:
platespin.freeze.sh is a shell script to contain the freeze logic.
platespin.thaw.sh is a shell script to contain the thaw logic.
platespin.conf is a text file that defines any required arguments, along with a timeout value.
The required format for the contents of the platespin.conf file is:
[ServiceControl]
(optional) FreezeArguments=<arguments>
(optional) ThawArguments=<arguments>
(optional) TimeOut=<timeout>
Replace <arguments> with the required command arguments, separated by a space, and <timeout> with a timeout value in seconds. If unspecified, the default timeout is used (60 seconds).
Save the scripts, along with the .conf file, on your Linux source workload, in the following directory:
/etc/platespin/