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EMC Timefinder Commands

The following are the Timefinder Procedural Commands

It outlines everything that needs to be done from start to finish. Realize that for routine operations, some of these steps won’t be needed; however, for the sake of completeness.

Prepare EMC structures

1. Create a Symmetrix disk group

symdg -t [ Regular | RDF1 | RDF2 ] create ${group}

2. Add devices to the disk group

symld -g ${group} add pd /dev/dsk/c#t#d#
symld -g ${group} add dev 01a

3. Associate BCV devices to the disk group

symbcv -g ${group} associate pd ${bcv_ctd}
symbcv -g ${group} associate dev ${bcv_dev}

Establish BCV mirrors

1. ID the logical device names: Timefinder defaults to using the logical device names. You can id the logical device names by:

symmir -g ${group} query

2. First time establish, execute a full establish:

symmir -g ${group} -full establish ${std_log_dev} bcv ${bcv_log_dev}

3. Use symmir query to monitor progress.

symmir -g ${group} query

Break BCV mirrors

1. Types of splits:

1. Instant split: Split is performed in the background after the completion of the split I/O request.
2. Force split: Splits the pair during establish or restore operations; invalid tracks may exist.
3. Reverse split: Resyncs the BCV with the full data copy from its local or remote mirror.
4. Reverse differential split: Enables a copy of only out-of-sync tracks to the BCV from its mirror.
5. Differential split: Enables a copy of only the updated tracks to the BCV’s mirror.

2. Commands:

symmir -g ${group} split
symmir -g ${group} split -instant
symmir -g ${group} split -differential
symmir -g ${group} reverse split -differential

Reestablish or restore BCV mirrors

1. Restore copies data from BCV back to standard pair. >Reestablish, on the other hand, does a differential update of the BCV from the standard device.

2. Commands:
symmir -g ${group} establish Differential reestablish from standard device to BCV
symmir -g ${group} -full restore Full restore of all tracks on BCV to standard device.
symmir -g ${group} restore Differential restore of BCV data to standard device.

The Timefinder Strategies are as follows

1. Maintain BCV mirrors with the standard device; break the mirrors when you want to backup, test, or develop on a copy of the original.

This is probably the most common way of running Timefinder. The advantage is that the split operation will happen almost instantly as the mirrors are fully synced all the time. The disadvantage is that anything towards that happens to the standard device will be reflected in the BCV mirror.

2. Maintain the BCV as a split device to keep an online backup of the original data.