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Server configuration
12 Dell EMC SC Series: Red Hat Enterprise Linux Best Practices | CML1031
2.3.1 SAS drivers
Since RHEL 6.5, SAS drivers are preloaded into certain Linux kernels. The existence of the SAS drivers can
be validated with the following commands. As a best practice, validate the driver versions with the Dell EMC
Storage Compatibility Matrix and use the latest supported driver as indicated.
# lsmod | grep sas
mpt3sas 188001 4
scsi_transport_sas 35588 1 mpt3sas
raid_class 4388 1 mpt3sas
megaraid_sas 96205 2
# modinfo mpt3sas | grep description
description: LSI MPT Fusion SAS 3.0 Device Driver
2.3.2 FC/iSCSI and SAS
The use of a mixed FC/iSCSI and SAS-connected environment on the same Linux system is not validated nor
supported. Maintain and operate a SAS-connected Linux system separately from other Linux systems using
FC/iSCSI connectivity.
2.3.3 SAS queue depth
Currently supported SAS HBAs default to a queue depth of 254 for each volume. Keep this factory-default
value unless directed by support- or application-specific directives.
# lsscsi -l
[1:0:0:1] disk COMPELNT Compellent Vol 0606 /dev/sdb
queue_depth=254
[1:0:1:1] disk COMPELNT Compellent Vol 0606 /dev/sdc
queue_depth=254
2.3.4 Boot-from-SAS
Boot-from-SAS functionality is not validated nor supported in use with Dell EMC 12Gbps SAS HBAs on Linux.
2.4 Software iSCSI
Most major Linux distributions support iSCSI and include a software iSCSI initiator. RHEL systems utilize the
open-iSCSI implementation of software iSCSI on the Linux platform. While iSCSI is a mature technology that
allows organizations to economically scale, it has grown in complexity at both the hardware and software
layers. The scope of this document is limited to the default Linux iSCSI software initiator, open-iSCSI. For
more advanced implementations (for example, leveraging iSCSI HBAs or drivers that make use of iSCSI
offload engines) consult the vendor documentation and services.
For instructions on setting up an iSCSI network topology, consult the SC Series Deployment Guide for the
respective model at the SC Series customer portal (login required).