HP StorageWorks XP Disk Array Configuration Guide (T5278-96047, May 2011)

Table 24 Device parameters-queue depth (IBM AIX)
Recommended ValueParameter
32
Queue depth per LU
1024
Queue depth per port (MAXTAGS)
The recommended queue depth settings might not provide the best I/O performance for your
system. You can adjust the queue depth setting to optimize the I/O performance of the disk array.
Displaying the device parameters using the AIX command line
At the command line prompt, enter lsattr -E -l hdiskx, where hdiskx is the device file
name.
Example
# lsattr –E -l hdisk2
Changing the device parameters using the AIX command line
1. To change the R/W timeout parameter, enter:
chdev –1 hdiskx –a rw_timeout='60'
2. To change the queue depth parameter, enter:
chdev –l hdiskx –a queue_depth='x'
where x is a value from the previous table.
3. To change the queue type parameter, enter:
chdev –l hdiskx –a q_type='simple'
For example, enter the following command to change the queue depth for the device hdisk3:
# chdev –l hdisk3 –a queue_depth='2'
4. Verify that the parameters for all devices were successfully changed.
For example, enter the following command to verify the parameter change for the device
hdisk3:
# lsattr –E –l hdisk3
5. Repeat these steps for each OPEN-x device on the disk array.
TIP: The lsattr command also shows useful information, such as LUN ID of the mapped
LDEV, worldwide name of the disk array FC port, and N-Port ID.
Another useful command for determining the slot position and port worldwide name of the
FCA is the lscfg –v –l hdiskx command.
Changing the device parameters using SMIT
1. Start SMIT. (Optional) For an ASCII session, use the smit –C command.
2. Select Devices.
Example
System Management
Move cursor to desired item and press Enter.
Software Installation and Maintenance
Software License Management
Devices
System Storage Management (Physical & Logical Storage)
108 IBM AIX