Did you follow the directions at
This is the only way to get reasonable performance when
using the POWER8 high function backplane or features 5913, ESA3, & EJ0L
I suspect on POWER7 you were using either its CEC high function backplane
or the feature 5903 adapters.
Kirk Goins <kirkgoins@xxxxxxxxx> wrote on Fri, 22 Aug 2014
Brand New 6core 128GB Mem
18 disk bay backplane with High Cache Internal Controller
EXP24S with 20 300GB drives
VIOS with3cores an d16GB Mem
Created 20 100GB vSCSI Drives for IBM i ( sees 95.5GB each )
10 each on 2 vSCSi Controllers
IBM i LIC install 8-10min ( normal is 3 to 5min )
IBM i Group1 DVD just took over 3.5hrs to install
VIOS TOPAS shows Disk at or near 100% Busy
Spent almost 3hrs on the phone with IBM and best thay could do
is have me collect snap and a perf collection and send it.
They tell that from VIOS or AIX they can't tell if the Disk
Cache is working or not. Best I can Tell from smit is it look
like the controllers are working, but I can't get IBM to help
look and tell if what I see is right , wrong or ??
Any Help or ideas would be of great in trying to diagnose this