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creating block special devices such as /dev/sdb and /dev/sdc as some
implementations might create naming fragmentation and a moving target.
nocache attribute instructs CLI to disable the write cache on the migrated
unit. Enabling write cache increases write performance at the cost of potential
data loss in case of sudden power loss (unless a BBU or UPS is installed). By
default the cache is enabled. To avoid the possibility of data loss in the event
of a sudden power loss, it is recommended not to set nocache unless there is a
BBU (battery backup unit) or UPS (uninterruptable power supply) installed..
autoverify attribute enables the autoverify attribute on the unit that is to be
migrated. For more details on this feature, see "/cx/ux set autoverify=on|off"
on page 59.
Migration Process
In all cases of migration, the background migration process must be
completed before the newly sized unit is available for use. You can continue
using the original unit during this time. Once the migration is finished, a
reboot will be required if you are booted from the unit. For secondary storage,
depending on your operating system, you may need to first unmount the unit,
then use CLI commands to 'export' and 'rescan' the unit so that the operating
system can see the new capacity, and then remount the unit. For details see "/
cx/ux export [noscan] [quiet]" on page 57 and "/cx rescan [noscan]" on
page 39.
You may also need to resize the file system or add a new partition. For
instructions, consult the documentation for your operating system.
Example of
//localhost> /c1/u3 migrate type=single
Indicates that u3 is a TWINSTOR or RAID-1 and the Migrate command splits
u3 to u3 and ux with a RAID type of Single.
Example of capacity expansion
//localhost> /c0/u0 migrate type=raid10 disk=3-4 stripe=16
Indicates that the destination unit has a RAID type of raid10 and has the disk
3 and 4 in addition to all the disks in the existing unit u0.
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It is important that you allow migration to complete
Warning:
before adding drives to the unit. Making physical changes to the
unit during migration may cause the migration process to stop, and
can jeopardize the safety of your data.
splitting a mirror
Unit Object Commands
65
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