7.3.7
Formatting a Logical Unit
Note 1: For the logical unit that is being formatted in the background, it is best to perform
operations to the host installation.
If a volatile failure for data in cache memory occurs due to subsystem power-off during
formatting, the logical unit will be unformatted and data can be lost. Therefore, host
installation operation should be performed from the first step for the logical unit.
Note 2: When logical units are formatted, the user data will be initialized and completely
deleted.
Note 3: RAID group allocated to NAS system LU used and user LU at the time of NAS
connection cannot be deleted without releasing the allocation.
Note 4: Formatting will impact the host access performance, especially on the logical unit
being formatted and on the logical unit in the same RAID group as the logical unit being
formatted. Execute formatting during off-hours with less host access.
When formatting the logical unit in the same RAID group as NAS system LU, do not boot or
reboot the NAS OS. This could result in boot failure or increase in boot time of NAS OS.
Format
This mode enables the subsystem to start its operation earlier by formatting the
specified LU in the background to make it usable by a host. Up to 512 LUs can be
specified for formatting. This number can also be increased; however, the number of
LUs that can be simultaneously formatted in the background is six per CTL. When
executing formatting, the Storage Navigator Modular program can perform operations
(such as a RAID group creation) while the formatting is being executed.
When the Storage Navigator Modular program is terminated while formatting is executed,
the formatting function is continued. When the Storage Navigator Modular program is
terminated while formatting is executed, the formatting progress is displayed by
percentage in the logical unit status column when the Storage Navigator Modular
program is activated again.
When the host I/O is executed for the LU in formatting, Format completion may be
delayed; from the 99 % progress status, it may take 400 seconds (maximum).
To format a logical unit, follow these steps:
1. Click the icon of a logical unit in the Unit window. On the Settings menu, select Logical
Unit, and then click Format.
Note 1 When you select multiple logical units, hold down the Ctrl key and click the icons of
the logical units to format.
When a logical unit is incorrectly specified, press the Cancel button and redo processing by
selecting a logical unit to be reformatted.
Note 2: In the ShadowImage in-system replication, or Copy-on-write SnapShot, PAIR cannot
be defined for the LU being formatted. LU defined as PAIR cannot be formatted.
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