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42 Dell EMC SC Series: Red Hat Enterprise Linux Best Practices | CML1031
1. Click Advanced Options.
2. Uncheck the Restrict Mapping Paths checkbox and select the controller in which to pin the volume
for mapping to the server object.
4.3 Understanding HBA queue depth
Queue depth refers to the number of pending I/O requests. Modifying this value can lead to an improvement
in I/O performance in some workloads. Generally, increasing queue depth can increase throughput, but
caution should be taken since increasing this value can also lead to higher latency. Different applications may
benefit from increasing this value, such as environments where the bulk of I/O consists of small reads and
writes. In environments defined by lower IOPS requirements that need higher throughput, having a lower
queue depth setting might be sufficient to meet and achieve the optimal levels of performance.
Consult section 2 for details on modifying this value for the particular HBA model being used.
4.4 SCSI UNMAP/TRIM
Since RHEL 6, the storage stack supports the SCSI UNMAP/TRIM specifications. The application and use of
SCSI UNMAP/TRIM in filesystem use cases can be very effective towards storage and cost management in
the business enterprise. However, consideration should also be made in regard to how this function is
implemented.
The discard mount parameter would enable the filesystem to perform real-time, on-demand SCSI UNMAP
commands to the SC Series array. In high-I/O-based application landscapes, this may introduce