Permitted Relayout Transformations

The tables below give details of the relayout operations that are possible for each type of source storage layout

Supported Relayout Transformations for Unmirrored Concatenated Volumes

Specifying a Non-Default Layout

You can specify one or more relayout options to change the default layout configuration. Examples of these options are:

ncol=number specifies the number of columns

ncol=+number specifies the number of columns to add

ncol=-number specifies the number of colums to remove

stripeunit=size specifies the stripe width

See the vxassist(1M) manual page for more information about relayout options.

The following are some examples of using vxassist to change the stripe width and number of columns for a striped volume in the disk group dbaseg:

The next example changes a concatenated volume to a RAID-5 volume with four columns:

Specifying a Plex for Relayout

Any layout can be changed to RAID-5 if there are sufficient disks and space in the disk group. If you convert a mirrored volume to RAID-5, you must specify which plex is to be converted. All other plexes are removed when the conversion has finished, releasing their space for other purposes. If you convert a mirrored volume to a layout other than RAID-5, the unconverted plexes are not removed. You can specify the plex to be converted by naming it in place of a volume:

Tagging a Relayout Operation

If you want to control the progress of a relayout operation, for example to pause or reverse it, use the -t option to vxassist to specify a task tag for the operation. For example, this relayout is performed as a background task and has the tag myconv:

See the following sections, Viewing the Status of a Relayout and Controlling the Progress of a Relayout, for more information about tracking and controlling the progress of relayout.

Viewing the Status of a Relayout

Online relayout operations take some time to perform. You can use the vxrelayout command to obtain information about the status of a relayout operation. For example, the command:

might display output similar to this:

In this example, the reconfiguration of a striped volume from 5 to 6 columns is in progress, and is just over two-thirds complete.

See the vxrelayout(1M) manual page for more information about this command.

If you specified a task tag to vxassist when you started the relayout, you can use this tag with the vxtask command to monitor the progress of the relayout. For example, to monitor the task tagged as myconv, enter:

Controlling the Progress of a Relayout

You can use the vxtask command to stop (pause) the relayout temporarily, or to cancel it altogether (abort). If you specified a task tag to vxassist when you started the relayout, you can use this tag to specify the task to vxtask. For example, to pause the relayout operation tagged as myconv, enter:

To resume the operation, use the vxtask command:

For relayout operations that have not been stopped using the vxtask pause command (for example, the vxtask abort command was used to stop the task, the transformation process died, or there was an I/O failure), resume the relayout by specifying the start keyword to vxrelayout, as shown here:

The -o bg option restarts the relayout in the background. You can also specify the slow and iosize option modifiers to control the speed of the relayout and the size of each region that is copied. For example, the following command inserts a delay of 1000 milliseconds (1 second) between copying each 10-megabyte region:

The default delay and region size values are 250 milliseconds and 1 megabyte respectively.

To reverse the direction of relayout operation that is currently stopped, specify the reverse keyword to vxrelayout as shown in this example:

This undoes changes made to the volume so far, and returns it to its original layout.

If you cancel a relayout using vxtask abort, the direction of the conversion is also reversed, and the volume is returned to its original configuration.

See the vxrelayout(1M) and vxtask(1M) manual pages for more information about these commands. See Managing Tasks with vxtask for more information about controlling tasks in VxVM.