Detecting virtual log devices

After a VIOS administrator has created virtual log devices and attached them to a client LPAR , the client LPAR device configuration must be refreshed for the devices to be visible.

The client LPAR administrator refreshes the settings by using one of the following methods:

Rebooting the client LPAR
Running the cfgmgr command

Run the lsdev command to display the virtual log devices. The devices are prefixed with vlog by default. An example of the lsdev command output on an AIX® LPAR on which two virtual logs devices are present is as follows:

lsdev
vlog0		Virtual Log Device
vlog1		Virtual Log Device

Inspect the properties of an individual virtual log device by using the

lsattr –El
<device name>

command, which produces output that is similar to the following :

lsattr –El vlog0
PCM                        Path Control Module            False
client_name    dev-lpar-05 Client Name                    False
device_name    vlsyslog0   Device Name                    False
log_name       syslog      Log Name                       False
max_log_size   4194304     Maximum Size of Log Data File  False
max_state_size 2097152     Maximum Size of Log State File False
pvid           none        Physical Volume Identifier     False

This output displays the client name, device name, and the amount of log data that VIOS can store.

The virtual log stores two types of log data, which are:

Log data: The raw log data generated by applications on the AIX LPAR .
State data: Information about when the devices were configured, opened, closed, and other operations that are used to analyze log activity.

The VIOS administrator specifies the amount of log data and state data that can be stored for each virtual log, and the amount is indicated by the max_log_size, and max_state_size attributes. When the amount of stored data exceeds the specified limit, the earliest log data is overwritten. The VIOS administrator must ensure that the log data is collected and archived frequently to preserve the logs.