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According to the HDS knowledge article HDS17320, the following will apply
if the AIX settings are not the same for each AIX host attached to the same port.
SSB - D052 means  incorrect AIX configuration
The error paramchgnotify can potentially cause significant host performance
degradation
SSB error code D052 afcuaext  paramchgnotify
This is created when the port detects an AIX Host access to a LUN and the
AIX Host has different AIX Characteristics Parameters than the last AIX
Host access down this port.
This situation arises when multiple AIX Hosts can access the same port (SAN
Switched environment), but the Hosts have not been setup properly with
identical AIX Characteristics Parameters. The AIX Characteristics
Parameters are:
1.  Q-Depth
2.  Q-Type
3.  R/W-TOV
4.  Q-Err bit
There is a fair amount of overhead in the routines associated with adapting
from one set of Host parameters to another which can lead to significant
Host Performance Degradation.  After adding disks to an AIX server you
should ensure that the QDEPTH, QTYPE and TIMEOUT value are correctly set.
Please refer to the current server / storage configuration guide to find
out the correct values and how to set them in the server.
These values MUST be consistent per port and per volume group.

1. Enter smit on the command line to start SMIT?.
2. On the SMIT? System Management panel, select Devices to bring up the
Devices panel.
3. Select Fixed Disk to bring up the Fixed Disk panel.
4. Select Change/Show Characteristics of a Disk to bring up the Disk panel.
5. Select the desired device from the Disk menu to bring up the Change/Show
Characteristics of a Disk panel.
6. Enter the desired queue depth, queue type [simple], and read/write
time-out value [60]. Press Enter to complete the parameter changes.
7. Repeat steps 5 and 6 for each new device on the 9900V subsystem.
8. Verify that the parameters for all devices were successfully changed by
entering the following command:
#lsattr -E -1 hdiskx
Example of SMIT:
Change/Show Characteristics of a Disk
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[MORE...4]
Status
Location
Parent adapter
Connection address Physical volume IDENTIFIER
ASSIGN physical volume identifier          no
Queue DEPTH                               [8]
Queuing TYPE                              [simple]
Use QERR Bit                              [yes]
Device CLEARS its Queue on Error          [no]
READ/WRITE time out value                 [60]
START unit time out value                 [60]
REASSIGN time out value                   [120]
APPLY change to DATABASE only              no
F1=Help F2=Refresh F3=Cancel F4=List F5=Reset F6=Command F7=Edit F8=Image
F9=Shell F10=Exit Enter=Do
To change the device parameters from the AIX? command line:
1. To display the parameters for the specified device, at the AIX? command
line prompt, enter:
#lsattr -E -l hdiskx
Note:  hdiskx  is the device file name, for example, hdisk2.
#lsattr -E -1 hdisk1
scsi_id                 0xef
lun_id                  0x0
location
ww_name                 0x500490e802757500
pvid                    000432871c6bbceb0000000000000000
queue_depth             2
q_type                  simple
q_err                   yes
clr_q                   no
rw_timeout              60
start_timeout           60
reassign_to             120
2. Change the device parameters by using:
#chdev -l hdiskx -a rw_timeout= 60  -a q_type= simple  -a queue_depth= x
Note: x is used to indicate the desired queue depth
3. Repeat steps (1) and (2) for each new device on the 9900.
4. Verify that the parameters for all devices were successfully changed by
entering the following command:
#lsattr -E -1 hdiskx

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