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Performance tuning
41 Dell EMC SC Series: Red Hat Enterprise Linux Best Practices | CML1031
The following output presents the active tuning profile (default) as well as the list of alternative tuning profiles
that can be applied. It is recommended to use the default tuning profile, throughput-performance, with any
SC Series storage implementation. The discussion of each tuning profile and its merits are outside the scope
of this paper, and further discussion of this topic can be found in Red Hat documentation.
Show currently active tuning profile:
# tuned-adm active
Current active profile: throughput-performance
Show all available tuning profiles:
# tuned-adm list
Available profiles:
- balanced
- desktop
- latency-performance
- network-latency
- network-throughput
- powersave
- sap
- throughput-performance
- virtual-guest
- virtual-host
Show the contents of tuning profiles:
The contents of the tuning profiles are located in /usr/lib/tuned/<PROFILE_NAME>/tuned.conf.
# cat /usr/lib/tuned/throughput-performance/tuned.conf
Apply a tuned profile:
# tuned-adm profile latency-performance
4.2 Using multiple volumes
A volume is only active on one SC Series controller at any one time. Where possible, distribute the volume
workload evenly across both SC Series storage controllers to most effectively leverage simultaneous I/O
processing. A larger number of smaller-sized volumes will often result in better performance than fewer
larger-sized volumes. From a Linux perspective, having multiple target volumes can result in performance
improvements by leveraging the kernel to process I/O in parallel to addressing multiple paths and SCSI
devices.
In SAS-connected environments, paths from both controllers are presented to the connected host
(active/optimized and standby). However, only the active/optimized path is used for all active I/O at any one
time. When the active/optimized path becomes unavailable, the SC Series array will dynamically determine
which one of the remaining standby paths will assume the role of the active/optimized path and continue to
stream active I/O to the new active/optimized path. This is accomplished by explicitly pinning volumes to a
different controller when mapping these volumes to the server object. This feature is accessible using the
Advanced Options on the mapping dialog shown as follows.