IBM N Series, Hardware Manual

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IBM System Storage N series Hardware Guide
Revert considerations
The N series does not support NDU for the revert process for DOT 8 7-mode. The following
restrictions apply to the revert process:
򐂰 User data is temporarily offline and unavailable during the revert.
򐂰 You must plan when the data is offline to limit the unavailability window and make it fall
within the timeout window for the Host attach kits.
򐂰 You must disable DOT 8.x 7-mode features before reverting.
򐂰 The 64-bit aggregates and 64-bit volumes cannot be reverted. Therefore, the data must be
migrated.
򐂰
You cannot revert while an upgrade is in progress.
򐂰 The revert_to command reminds you of the features that must be disabled to complete
the reversion.
򐂰 FlexVols must be online during the reversion.
򐂰 Space guarantees should be checked after the reversion.
򐂰 You must delete any Snapshots that are made on Data ONTAP 8.0.
򐂰 You must initialize again all SnapVault relationships after the revert because all snapshots
that are associated with Data ONTAP 8.0 are deleted.
򐂰
SnapMirror sources must be reverted before SnapMirror destinations are reverted.
򐂰 A revert cannot be nondisruptive, so plan for system downtime.
Example 21-1 shows details of the revert_to command.
Example 21-1 revert_to command
TUCSON1> revert_to
usage: revert_to [-f] 7.2 (for 7.2 and 7.2.x)
revert_to [-f] 7.3 (for 7.3 and 7.3.x)
-f Attempt to force revert.
TUCSON1>
You cannot revert while the upgrade is still in progress. Use the command that is shown in
Example 21-2 on page 300 to check for upgrade processes that are still running.
Example 21-2 WAFL scan status
TUCSON1> priv set advanced
Warning: These advanced commands are potentially dangerous; use
them only when directed to do so by IBM
personnel.
TUCSON1*> wafl scan status
Volume vol0:
Scan id Type of scan progress
1 active bitmap rearrangement fbn 454 of 1494 w/ max_chain_len 7
...