Veritas Volume Manager 5.0 Administrator's Guide (September 2006)

243Creating volumes
Creating a volume with dirty region logging enabled
# vxdg upgrade diskgroup
For more information, see “Upgrading a disk group” on page 200.
2 Use the following command to create the volume (you may need to specify additional
attributes to create a volume with the desired characteristics):
# vxassist [-g diskgroup] make volume length layout=layout \
logtype=dco dcoversion=20 [drl=on|sequential|off] \
[ndcomirror=number] [fastresync=on] [other attributes]
Set the value of the drl attribute to on if dirty region logging (DRL) is to be used
with the volume (this is the default setting). For a volume that will be written to
sequentially, such as a database log volume, set the value to
sequential to enable
sequential DRL. The DRL logs are created in the DCO volume. The redundancy of
the logs is determined by the number of mirrors that you specify using the
ndcomirror attribute.
By default, Persistent FastResync is not enabled on newly created volumes. Specify
the
fastresync=on attribute if you want to enable Persistent FastResync on the
volume.
For more information, see the vxassist(1M) manual page.
Note: See “Determining the DCO version number” on page 269 for details of how to
determine the version number of a volume’s DCO.
Creating a volume with dirty region logging enabled
Note: The procedure in this section is applicable to volumes that are created in disk groups
with a version number of less than 110. To enable DRL or sequential DRL on a volume
that is created within a disk group with a version number of 110 or greater, follow the
procedure described in “Creating a volume with a version 20 DCO volume” on page 242,
which creates the DRL logs within the plexes of a version 20 DCO volume.
Dirty region logging (DRL), if enabled, speeds recovery of mirrored volumes after a
system crash. To enable DRL on a volume that is created within a disk group with a
version number between 20 and 100, specify the
logtype=drl attribute to the vxassist
make command as shown in this example usage:
# vxassist [-g diskgroup] make volume length layout=layout \
logtype=drl [nlog=n] [loglen=size] [other attributes]
The nlog attribute can be used to specify the number of log plexes to add. By default, one
log plex is added. The loglen attribute specifies the size of the log, where each bit
represents one region in the volume. For example, the size of the log would need to be
20K for a 10GB volume with a region size of 64 kilobytes.