Sun Java System Application Server Enterprise Edition 8.1 2005Q2 High Availability Administration Guide

Getting Device Information

Monitor free space in HADB data (disk storage) devices:

Use the hadbm deviceinfo command to get information about free space in data devices. This command displays the following information for each node of the database:

The command syntax is:

hadbm deviceinfo  [--details]  
[--adminpassword=password | --adminpasswordfile=file]  
[--agent=maurl]  [dbname]

The dbname operand specifies the database name. The default is hadb.

The --details option displays the following additional information:

See General Options for a description of other command options.

For more information, see hadbm-deviceinfo(1).

To determine the space available for user data, take the total device size, then subtract the space reserved for HADB: four times the LogBufferSize + 1% of the device size. If you do not know the size of the log buffer, use the command hadbm get logbufferSize. For example, if the total device size is 128 MB and the LogBufferSize is 24 MB, the space available for user data is 128 – (4 x 24) = 32 MB. Of the 32 MB, half is used for replicated data and around one percent is used for the indices, and only 25 percent is available for the real user data.

The space available for user data is the difference between the total size and reserved size. If the data is refragmented in the future, the free size must be approximately equal to 50% of the space available for user data. If refragmentation is not relevant, the data devices can be exploited to their maximum. Resource consumption warnings are written to the history files when the system is running short on device space.

For more information about tuning HADB, see the Sun Java System Application Server Performance Tuning Guide.

Example 3–16 Example of getting device information

The following command:

hadbm deviceinfo --details

Displays the following example results:

NodeNO Totalsize Freesize Usage NReads NWrites DeviceName
0      128       120      6%    10000  5000    C:\Sun\SUNWhadb\
1      128       124      3%    10000  5000    C:\Sun\SUNWhadb\
2      128       126      2%     9500  4500    C:\Sun\SUNWhadb\
3      128       126      2%     9500  4500    C:\Sun\SUNWhadb\