====== JFS2 sync time exceeded 600 seconds ======

File system level:
--> the jfs2 buffers need to be increased (dynamic):
<cli prompt='#'>
# ioo -p -o j2_dynamicBufferPreallocation=256
</cli>

service queue_depth on the hdisk devices:
--> I would recommend you to increase the service queue_depth from 32 to 48 or to 64.
--> please talk to the storage support about this also, as this is not the only LPAR connected to this storage box.

For example, I start with a queue_depth of 32, which is confirmed by looking at lsattr (ODM) and kdb (running config) output:
<cli prompt='#'>
# lsattr -El hdisk6 -a queue_depth
queue_depth 32 Queue DEPTH True
</cli>

<cli prompt='#'> 
# echo scsidisk hdisk6 | kdb | grep queue_depth
    ushort queue_depth  = 0x20;        < In Hex.
# echo "ibase=16 ; 20" | bc
          32
</cli>