Rebuild logging

Question

Hello, There is a white paper titled 'EMC CLARiion Global Hot Spares and Proactive Hot Sparing, Best Practiceslanning'. On page 10, it writes about Rebuild logging. Is this log configurable? Where is the log being stored? is it on the hot spare? Thanks, Mouis

mouis1 · Answer

the document says that rebuild logging is avaialble as of Flare 24. I guess then this feature is not available to AX4-5, since the latest flare is 23. Am i correct?

kelleg · Answer

yes - AX4 uses flare 23 - there should be a newer flare coming out in the near future - not sure if the logging feature will be included as we have not seem the release notes yet.glen

RyanP2 · Answer

First off the rebuild log is not configurable by any means.

The newer flare codes have a new drive state (drive in probation) while the drive is unavailable for whatever reason. The probational state only lasts for less than 5 minutes, and if the drive does not respond in this 5 minutes, the drive is marked dead.

This state is used so that less drives are failed because they were unresponsive for a second or two.

The rebuild log is just a log that says what data block changed on that drive while the SP couldn't talk to it. If the drive comes back up, all changed data is sent to the drive from write cache and no need for further rebuilding. If the drive goes to failed, a full rebuild is needed to the hot spare.

Log is most likely saved on the SP as the hot spare is not engaged for a drive in probation.

DGM3 · Answer

Please also see the whitepaper 'EMC CLARiiON Global Hot Spares and Proactive Hot Sparing - Best Practices Planning' on Powerlink, for discussion of Rebuild Logging.Regards,DGM

mouis1 · Answer

Thanks to all.

CLARiiON

Rebuild logging

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