Adding a DCM log


Adding a DCM log
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The vxassist addlog command with its parameters enables you to add a log (DRL or DCM) or DCO to a volume. For Volume Replicator purposes, the DCM is the only log that we need to add. The DCM log is a data change map, used for fast resynchronization of a Secondary RVG with the Primary RVG when the Replicator Log overflows. It is also used for failback logging in the case of a takeover with fast-failback.

Syntax for vxassist addlog command

vxassist [-g<DynamicDiskGroupName>] \
addlog <VolumeName|DriveLetter|VmName|DrivePath> \
[LogType=<DRL | DCM | DCO>] [nlog=<#>] [<diskname | p#c#t#l#>...]

Table: Attributes for vxassist addlog command describes the attributes that you can specify with the vxassist addlog command.

Table: Attributes for vxassist addlog command

Attributes	Description
VolumeName	Specifies the DeviceName of the volume. For example, \HarddiskDmVolumes\<diskgroup>\<volume name>
DriveLetter	The drive letter of the volume.
VmName	Specifies the internal name for the volume, which you see when you use the vxvol volinfo <volume> command.
DrivePath	Specifies the drive path to volumes that are NTFS mounted.
Logtype	Specifies the type of log you want to add. This includes: DCM Adds a Data Change Map log. DRL Adds a Dirty Region Log to volumes. This is the default log type for mirrored volumes. DCO Adds a Data Change Object. This is used to implement Persistent FastResync.
nlog <>	Specifies the number of logs that need to be created for the specified volume.
Diskname	Indicates the designated hard disk, which can be specified by the device name (such as Harddisk2) or the internal disk name (such as Disk2).