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Dell HPC Lustre Storage solution with Intel Omni-Path
The max_pages_per_rpc parameter is a tunable that sets the maximum number of pages that
will undergo I/O in a single RPC to that OST.
[root@node057 ~]# lctl set_param osc.*.max_rpcs_in_flight=64
The max_rpcs_in_flight is a tunable that sets the maximum number of concurrent RPCs in
flight to the OST. This parameter in majority of cases will help with small file IO patterns.
[root@node057 ~]# lctl set_param llite.*.max_read_ahead_mb=1024
The max_read_ahead_mb is a tunable that sets the maximum amount of data readahead on a
file. These are read ahead in an RPC sized chunk.
[root@node057 ~]# lctl set_param osc.*.max_dirty_mb=1024
The max_dirty_mb is a tunable that sets how much dirty cache per OST can be written and
queued. This generally benefits large memory IO workloads.
[root@node057 ~]# lctl set_param osc.*.checksums=0
This tunable will disable checksums and overhead associated.
[root@node057 ~]# lctl set_param llite.*.max_cached_mb=40960
The max_cached_mb tunable is the maximum amount of inactive dta that will be cached by
the client.
[root@node057 ~]# lctl set_param llite.*.max_read_ahead_per_file_mb=1024
The max_read_ahead_per_file_mb is a tunable that sets maximum read ahead for each file.
[root@node057 ~]# lctl set_param debug=0
This tuning parameter will disable debugging completely and free the associated overhead.
[root@node057 ~]# lctl set_param subsystem_debug=0
The subsystem_debug parameter will control the debugging logs3 for subsystems.
5.2 Intel OPA specific tunings
[root@ieel3-oss1 ~]# cat /etc/modprobe.d/hfi1.conf
options hfi1 sge_copy_mode=2 wss_threshold=70 krcvqs=20
The sge_copy_mode tuning parameter introduces Adaptive Cache Memcpy feature that could
improve throughput for high concurrency patterns such as outstanding requests in flight.
The wss_threshold parameter is the working set size threshold percentage that works with
sge_copy_mode.
The krcvqs parameter is a tunable (kernel receive queues) that can improve parallel file
system scalability.