/cx/u
x migrate type=
RaidType [disk=
p:-p]
[group=3|4|5|6|7|8|9|10|11|12|13|14|15|16] [stripe=
Stripe] [noscan] [nocache] [autoverify]
The unit that results from the migration is subject to the same rules and policies that apply when creating a new unit with the
/cx add command. For example, a valid number of disks and parameters must be specified.
Note: Rapid RAID Recovery is always disabled for units that are migrated.
The destination unit must use all source disks and potentially augment the number of disks in the
disk=p:-p disk list.. (An exception to this is when migrating a RAID 1 to a unit of type single. For details, see the note below.) Unspecified parameters are assigned the default values (stripe size of 64K, write cache enabled, autoverify disabled, and ignoreECC disabled). Both source name and serial number will be carried over to the destination unit.
Note: A special case of this command is when the source unit has a type of RAID1 and destination unit has a type of single. In this case, the migrate command splits both drives into two identical single disks. (If you do this, unmount the unit first before splitting). The disk name will be duplicated on the destination units, but the source unit serial number will not be carried over to the new unit. The new destination unit will have its own serial number. In this case, the disk-specifier of the migration command [
disk=p:-p] must not be included in the command, because the source drives are the destination drives. Specifying more drives with the
disk= option would return an error
type=RaidType specifies the RAID type of the destination unit. Possible unit types include
raid0,
raid1,
raid5,
raid6,
raid10,
raid50, or
single.
For example, type=raid5 indicates the destination unit is RAID-5. The
type=single is a special case of the migrate command. It splits the source unit RAID-1 or TWINSTOR into multiple Single units.
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Note: You can only migrate a unit to a RAID level that has the same or more capacity as the existing one. A four-drive RAID 5 unit can migrate to a four-drive RAID 0, but a four-drive RAID 0 unit cannot migrate to a four-drive RAID 5, without adding another drive, due to the need for additional storage capacity for parity bits.
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disk=p:-p.. consists of a list of ports or VPorts (disks) to be used in addition to the source disks in the construction of the destination unit. One or more ports can be specified. Multiple ports can be specified using a colon (:) or a dash (-) as port index separators. A dash indicates a range and can be mixed with colons. For example
disk=0:1:2-5:9:12 indicates port or VPort 0, 1, 2 through 5 (inclusive), 9 and 12.
group=3|4|5|6|7|8|9|10|11|12|13|14|15|16 indicates the number of disks per group for a RAID 50 type. (This attribute can only be used when type=raid50.) Recall that a RAID 50 is a multi-tier array. At the bottom-most layer, N number of disks per group are used to form the RAID 5 layer. These RAID 5 arrays are then integrated into a RAID 0. This attribute allows you to specify the number of disks in the RAID 5 level. Valid values are 3 through 12. For example
group=3 indicates 3 disks of RAID 5 at the bottom layer of RAID 50.
Note: You can have a maximum of 4 subunits in a RAID 50 unit
Note that a sufficient number of disks are required for a given pattern or disk group. For example, given 6 disks, specifying 3 will create two RAID 5 arrays. With 12 disks, specifying 3 will create four RAID 5 arrays under the RAID 0 level. With only 6 disks a grouping of 6 is not allowed, as you would basically be creating a RAID 5.
The default RAID 50 grouping varies, based on number of disks. For 6 and 9 disks, default grouping is 3. For 8 disks, the default grouping is 4. For 10 disks, the default grouping is 5, and for 12 disks, the disks can be grouped into groups of 3, 4, or 6 drives (the group of 4 drives is set by default as it provides the best of net capacity and performance). For 15 disks, the disks can be grouped into groups of 5 drives (3 drive groups would make 5 subunits, you can have a maximum of 4 subunits). For 16 disks, the disks can be grouped into groups of 4 or 8 drives.
Note that RAID-10 always has group=2, so an attribute specifying it’s group is not necessary.
stripe=Stripe consists of the stripe size to be used. The following table illustrates the supported and applicable stripes on the respective unit types and controller models. Stripe size units are in KB (kilobytes).
noscan attribute instructs CLI not to notify the operating system of the creation of the new unit. By default CLI will inform the operating system. One application of this feature is to prevent the operating system from 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 but 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 (uninterruptible power supply) installed.
autoverify attribute enables the autoverify attribute on the unit to be migrated. For more details on this feature, see
/cx/ux set autoverify=on|off.
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 ‘remove’ and ‘rescan’ the unit so that the operating system can see the new capacity, and then remount the unit. For details see
/cx/ux remove [noscan] [quiet] and
/cx rescan [noscan].
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Warning: It is important that you allow migration to complete 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.
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//localhost> /c1/u3 migrate type=single
Sending migration message to /c1/u3 ... Done.
In this case, the command indicates that u3 should be split into Single units. In this case, u3 is a RAID 1 and the Migrate command splits u3 into u3 and u
x, each with a RAID type of Single.
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Warning: Make sure that no I/O is pending and that the unit is unmounted before splitting a mirror. If the RAID 1 is the boot device, you should boot from a different device before splitting the mirror.
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//localhost> /c0/u3 migrate type=raid10 disk=10-11 stripe=16
Sending migration message to /c0/u3 ... Done.
In this case, the command indicates that the source unit is u3 and the destination unit has a RAID type of raid10 and has added the disks 10 and 11 to the disks in the existing unit u3.
The following is an example of how migrating units will be displayed. In this example, the report indicates that
/c0/u3 is a migrating unit with 39% completion. The report also indicate that Source Unit
su0 is of type RAID-1 and Destination Unit
du0 is of type RAID-10.
3ware CLI> /c0 show
Unit UnitType Status %RCmpl %V/I/M Stripe Size(GB) Cache AVrfy
---------------------------------------------------------------------------
u0 RAID-5 OK - - 64K 596.004 ON OFF
u2 SPARE OK - - - 149.042 - OFF
u3 Migrator MIGRATING - 39 - 149.001 ON OFF
VPort Status Unit Size Blocks Serial
---------------------------------------------------------------
p0 OK u0 149.05 GB 312581808 WD-WCANM1771318
p1 OK u0 149.05 GB 312581808 WD-WCANM1757592
p2 OK u0 149.05 GB 312581808 WD-WCANM1782201
p3 OK u0 149.05 GB 312581808 WD-WCANM1753998
p4 OK u2 149.05 GB 312581808 WD-WCANM1766952
p5 OK u3 149.05 GB 312581808 WD-WCANM1882472
p6 OK u0 149.05 GB 312581808 WD-WCANM1883862
p7 OK u3 149.05 GB 312581808 WD-WCANM1778008
p8 OK - 149.05 GB 312581808 WD-WCANM1770998
p9 NOT-PRESENT - - - -
p10 OK u3 149.05 GB 312581808 WD-WCANM1869003
p11 OK u3 149.05 GB 312581808 WD-WCANM1762464
3ware CLI> /c0/u3 show
Unit UnitType Status %RCmpl %V/I/M Port Stripe Size(GB)
------------------------------------------------------------------------
u3 Migrator MIGRATING - 39 - - -
su3 RAID-1 OK - - - - 149.001
su3-0 DISK OK - - p5 - 149.001
su3-1 DISK OK - - p7 - 149.001
su3/v0 Volume - - - - - 149.001
du3 RAID-10 OK - - - 16K 298.002
du3-0 RAID-1 OK - - - - -
du3-0-0 DISK OK - - p5 - 149.001
du3-0-1 DISK OK - - p7 - 149.001
du3-1 RAID-1 OK - - - - -
du3-1-0 DISK OK - - p10 - 149.001
du3-1-1 DISK OK - - p11 - 149.001
du3/v0 Volume - - - - - 149.001
The migration path of raidtype Single to RAID-1 is a special case. Since the single unit would become a mirrored array, technically this is not a migration. As a result this command shows a different status than other migration paths. In addition, the status of the newly specified disk will show DEGRADED until the “migration/rebuild” is complete.
For example, below is a system with two migrating units, /c0/u0 and /c0/u1. u0 is migrating from a RAID-10 to a RAID-0 array, while u1 is migrating from Single to a RAID-1, initiated by the following commands:
/c0/u0 migrate type=raid0
/c0/u1 migrate type=raid1 disk=5
Note the difference in UnitType and
Status of u0 and u1, even though they are both migrating units.
3ware CLI> /c0 show
Unit UnitType Status %RCmpl %V/I/M Stripe Size(GB) Cache AVrfy
---------------------------------------------------------------------------
u0 Migrator MIGRATING - 26 - 298.002 ON OFF
u1 RAID-1 REBUILD-PAUSED 0 - - 372.519 OFF OFF
Port Status Unit Size Blocks Serial
---------------------------------------------------------------
p0 OK u0 149.05 GB 312581808 WD-WCANM1883862
p1 OK u0 149.05 GB 312581808 WD-WCANM1754124
p2 OK u0 372.61 GB 781422768 WD-WMAMY1661939
p3 OK u0 372.61 GB 781422768 WD-WMAMY1579179
p4 OK u1 372.61 GB 781422768 WD-WMAMY1662720
p5 DEGRADED u1 372.61 GB 781422768 WD-WMAMY1576310
p6 NOT-PRESENT - - - -
p7 NOT-PRESENT - - - -
3ware CLI> /c0/u3 show
Unit UnitType Status %RCmpl %V/I/M Port Stripe Size(GB)
------------------------------------------------------------------------
u0 Migrator MIGRATING - 26 - - -
su0 RAID-10 OK - - - 64K 298.002
su0-0 RAID-1 OK - - - - -
su0-0-0 DISK OK - - p0 - 149.001
su0-0-1 DISK OK - - p1 - 149.001
su0-1 RAID-1 OK - - - - -
su0-1-0 DISK OK - - p2 - 149.001
su0-1-1 DISK OK - - p3 - 149.001
su0/v0 Volume - - - - - 298.002
du0 RAID-0 OK - - - 64K 596.004
du0-0 DISK OK - - p3 - 149.001
du0-1 DISK OK - - p2 - 149.001
du0-2 DISK OK - - p1 - 149.001
du0-3 DISK OK - - p0 - 149.001
du0/v0 Volume - - - - - N/A
3ware CLI> /c0/u1 show
Unit UnitType Status %RCmpl %V/I/M Port Stripe Size(GB)
------------------------------------------------------------------------
u1 RAID-1 REBUILD-PAUSED 0 - - - 372.519
u1-0 DISK OK - - p4 - 372.519
u1-1 DISK DEGRADED - - p5 - 372.519
u1/v0 Volume - - - - - 372.519