User Guide

© 2021 IBM Corporation
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IBM
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Power
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PCIe3 x8 2-port Fibre Channel (32 Gb/s) Adapter
•
https://www.ibm.com/docs/en/aix/7.2?topic=io-
mpio-device-attributes
• https://www.ibm.com/docs/en/power9?topic=ch
annel-npiv-multiple-queue-support
Additional AIX tuning for performance:
• SCSI over Fiber Channel (MPIO) : set multipath
algorithm to round_robin for every hdisk
• NVMe over Fiber Channel : set nchan attribute to
7 for every NVMe over Fiber Channel Dynamic
controller created during discovery phase
NVMe Adapter AIX tuning for performance
• Set nchan attribute to 8 for each NVMe device
Power10 Quick Start Guide – Storage IO Considerations
• If you are using the same storage adapters as your previous system, initially, the same tuning should be used on the new system. If additional performance
is desired from the existing system, then normal tuning should be performed.
• If the storage subsystems are appreciably different on the newer system than the prior system, the following list of considerations could negatively impact
the perceived speed of applications –
o Changing from Direct Attached Storage (DAS or internal) to Storage Area Network (SAN) or Network Attached Storage (NAS) (or external storage) can
increase latency.
o Additional functions such as compression, encryption and deduplication can add latency.
o Reducing the number of Storage LUNs can reduce resources in the server needed to support required throughputs.
o Refer to tuning or setup guides for the new devices to understand these impacts.
o Virtualization does add latency and can reduce throughput compared to native I/O. Besides the backend hardware, ensure VIOS memory and CPU
o Moving to higher speed virtualized adapters in VIOS will require adjusting the VIOS configuration in CPUs and memory.
IBM PowerVM Best Practices
can be very helpful in VIOS sizing.
Tuning guidelines - please refer to the
IBM Knowledge Center for AIX and Linux guidelines.
PCIe3 12 GB Cache RAID + SAS Adapter Quad-port 6 Gb x8 Adapter
Linux:
• https://www.ibm.com/docs/en/power9/9223-42H?topic=availability-ha-asymmetric-
access-optimization
• https://www.ibm.com/docs/en/power9/9223-42H?topic=linux-common-sas-raid-
controller-tasks
AIX:
•
https://www.ibm.com/docs/en/power9/9223-42H?topic=aix-multi-initiator-high-
availability
• https://www.ibm.com/docs/en/power9/9223-42H?topic=aix-common-controller-disk-
array-management-tasks
IBM i:
• https://www.ibm.com/docs/en/power9/9223-42H?topic=configurations-dual-storage-
ioa-access-optimization
• https://www.ibm.com/docs/en/power9/9223-42H?topic=i-common-controller-disk-
array-management-tasks