This is a brief note about a new capability we have introduced starting GeoSynchrony 5.2. I have been seeing a bunch of questions on our internal mailing lists about this. Hopefully, this note addresses a bunch of them.
Why do you need it?
How the command works
Things to remember
There are a few things to remember while executing this command:
- This command will suspend host I/Os while the cache is being invalidated. Ideally, host I/Os should be stopped prior to invalidating cache. Remember that suspending I/Os on a live system could cause the host to detect a data unavailability (depending on how timing sensitive it is)
- This command performs pre-checks to see if the volume is healthy on all directors before executing. If the volume is not healthy, you will get warnings about this.
- The VPLEX cluster should not be undergoing an NDU while this command is being executed
- There should be no mirror rebuilds or migrations in progress for virtual volumes affected by this command
- No volume expansions (more about this in a later post) when this command is executed
Checking the status of the command
- in-progress: cache-invalidate is running.
- completed: cache-invalidate has completed execution successfully.
- error: cache-invalidate has finished but with error.
- unknown: This status is reported when a particular director where the command needed to be executed cannot be reached
- successful: cache-invalidate completed successfully.
- failure: cache-invalidate finished with failure. Cause field indicates the appropriate reason
- error: cache-invalidate is in error state.
- This is a text string indicating the reason for any failure / error during execution.
And from there you are good to go! Happy cache-invalidating! If you have any questions, please post them in the comments section.
Don Kirouac (@kirostor) made me aware via twitter of a whitepaper that describes the usage of cache invalidate. Thanks Don!
Finally, to all readers of this blog, a very Happy Holiday Season to you and your near and dear ones and Best wishes for 2014! We have some exciting stuff coming your way courtesy of the engineers working on VPLEX and RecoverPoint. And I cannot wait to tell you all about it … Stay tuned!