Use the Modifying Virtual Disks panel in the SAN Volume Controller Console to
change the attributes of a selected virtual disk (VDisk).
Introduction
You
can update the name, I/O group, and VDisk copy attributes on this
panel.
Important: - Do not move VDisks to an offline I/O group. Ensure that the I/O
group is online before you move VDisks to avoid any further data loss.
- Suspend I/O operations at the host level before you move VDisks.
You can migrate a single VDisk to a new I/O group to
manually balance the workload across the nodes in the cluster. This
avoids having a pair of nodes that are overworked and another pair
that are underworked. You can repeat this task for all VDisks to migrate
to a new I/O group.
Attention: - Determine which hosts use this VDisk. On these hosts, quiesce
all I/O operations for the VDisk and update the multipathing device
drivers configuration to remove all device identifiers that are presented
for a VDisk prior to moving the VDisk.
- Stop and delete all FlashCopy® mappings and Metro
Mirror or Global Mirror relationships
that use this VDisk.
Attributes
The
following attributes are displayed in the table:
- VDisk Name
- Displays the name of the selected VDisk.
- VDisk ID
- Displays the system-assigned ID for the selected VDisk.
- I/O Group
- Displays the I/O Group for which the selected VDisk is a member.
Note: If
you modify this value, you will be taken to the Modify VDisk Confirmation
panel.
- I/O Governing Rate
- Displays the maximum amount of I/O activity that host objects
can send to the selected VDisk.
- Unit Device Identifier
- Displays the unit device identifier as a decimal or hexadecimal
value. This field is used only by hosts that are using the OpenVMS
operating system. For other operating systems, setting a unit device
identifier is not required.
- Preferred Node
- Displays the current preferred node for the selected VDisk.
- Primary
- Displays the copy identifier for the primary VDisk copy. The
primary copy is chosen preferentially for read operations and in other
circumstances.
- Synchronization Rate
- Displays the current mirror synchronization rate for the VDisk
copies.
The following table shows the relationship of the
rate value to the data copied per second.
Table 1. Relationship between the rate value
and the data copied per second| User-specified rate attribute value |
Data copied/sec |
|---|
| 1 - 10 |
128 KB |
| 11 - 20 |
256 KB |
| 21 - 30 |
512 KB |
| 31 - 40 |
1 MB |
| 41 - 50 |
2 MB |
| 51 - 60 |
4 MB |
| 61 - 70 |
8 MB |
| 71 - 80 |
16 MB |
| 81 - 90 |
32 MB |
| 91 - 100 |
64 MB |
Fields
You
can update the following fields:
- New Name
- Enter the new name for the VDisk. You must use the following format:
- The name can be from 1 - 15 characters long.
- The name can include letters, numbers, hyphens, and underline
characters. It is not case-sensitive.
- The first character cannot be a number.
- The name cannot begin with the type of object. For example, vdisk0001 is
not valid.
- The first character cannot be a dash [ - ].
- I/O Group
- Select a new I/O group. Only I/O groups that are currently available
are listed.
- Preferred Node
- Select the preferred node for the VDisk. The nodes that are available
for selection are based on the selected I/O group.
- Force
- Select the force option to force the changes of the I/O group.
Use the force option in the following situations:
- The VDisk has the Fast Write State of either Not Empty or Corrupt.
If the state is Not Empty, selecting force discards
the cache and moves the VDisk to the new I/O group. In this case,
data might be lost. For the Corrupt state, the force option moves
the VDisk to the selected I/O group.
- The VDisk is a mirrored and has not finished synchronization of
the copies. If you select Force, synchronization is stopped
and the VDisk moves to the new I/O group. The VDisk is resynchronized
from the beginning in the new I/O group.
- I/O Governing
- Enter a number for the I/O governing rate for this VDisk. The
I/O governing rate allows you to set a limit on the amount of I/O
traffic. No I/O governing rate is set when a VDisk is created. To
reset the governing rate so that there is no I/O governing rate, enter
0.
- Rate
- Select the unit of measure to use for the I/O governing rate.
You can select the rate to be I/Os in seconds or megabytes (MB) in
seconds. The following values are possible:
- Unit Device Identifier
- Enter a unit device identifier as a decimal or hexadecimal value.
Valid input is a decimal number from 0 - 32767 or a hexadecimal value
from 0 - 0x7FFF. Hexadecimal values must be proceeded by 0x. For example,
0x1234. The default value is zero.
- Primary Copy
- Enter the copy identifier for the primary VDisk copy. The primary
copy is selected before other copies for read operations and in other
circumstances.
- Synchronization Rate
- Select the mirror synchronization rate for the VDisk. A value
of zero (0) disables synchronization. The default value is 50 (2 MB
per second).
The following table shows the relationship of the
rate value to the data copied per second.
Table 2. Relationship between the rate value
and the data copied per second| User-specified rate attribute value |
Data copied/sec |
|---|
| 1 - 10 |
128 KB |
| 11 - 20 |
256 KB |
| 21 - 30 |
512 KB |
| 31 - 40 |
1 MB |
| 41 - 50 |
2 MB |
| 51 - 60 |
4 MB |
| 61 - 70 |
8 MB |
| 71 - 80 |
16 MB |
| 81 - 90 |
32 MB |
| 91 - 100 |
64 MB |
- Copy ID
- Select the copy identifier for which you want to change the following
properties:
- Warn when used capacity of the VDisk reaches
- Specify a threshold to send a warning error for the VDisk when
the capacity that is used first exceeds the specified level. You can
either specify a percentage of VDisk capacity or enter a specific
amount of capacity to be allocated. If you enter a specific amount,
you must also select the units for the space. The following units
can be selected:
If you select Autoexpand, the default
value for the warning level is 80% of the virtual disk capacity. If Autoexpand is
not selected, the default value for the warning level is 80% of the
real capacity. To disable warnings, specify 0 or 0%.
- Autoexpand
- Select this option if you want the space-efficient copies to automatically
expand their real capacities by allocating new extents from their
MDisk group. Setting a space-efficient real size will protect the
copy from going offline when its MDisk group runs out of space.
Actions
The
following actions are available:
- OK
- Click this button to change the VDisk.
- Cancel
- Click this button to exit the panel without changing the VDisk.