Developers Guide

Server configuration
33 Dell EMC SC Series with Red Hat Enterprise Linux 7x | CML1071
3.3.2 SAS /etc/multipath.conf
Add the following device schema to the /etc/multipath.conf file that is used exclusively for SAS-connected
Linux hosts. This schema defines the configuration parameters for all devices identified by
vendor=”COMPELNT” and product=”Compellent Vol”. This schema is typically added after the defaults
schema and before the blacklist_exceptions schema.
devices {
device {
vendor COMPELNT
product "Compellent Vol"
path_checker tur
prio alua
path_selector "service-time 0"
path_grouping_policy group_by_prio
no_path_retry 24
hardware_handler "1 alua"
failback immediate
rr_weight priorities
}
}
3.3.3 FC/iSCSI and SAS
The use of a merged FC/iSCSI and SAS-connected environment on the same Linux host is not validated nor
supported. Maintain and operate a SAS-connected Linux host separately from other Linux hosts using
FC/iSCSI connectivity.
The SAS-specific multipath.conf configuration schema can be merged with a FC/iSCSI-based
/etc/multipath.conf file.
3.3.4 Identify SAS devices on Linux
This sample script parses the Linux /sys filesystem and displays the contents of the files located and identified
as host_sas_address. The contents of this file represents the device name of the installed SAS HBA.
In the following instance, two SAS HBA cards are identified with their device names shown accordingly. This
script works for both RHEL 6.x and RHEL 7.x Linux hosts.
# for i in `find /sys/devices -name host_sas_address`; do echo "=== $i"; cat $i;
echo; done
===
/sys/devices/pci0000:40/0000:40:01.0/0000:41:00.0/host1/scsi_host/host1/host_sas
_address
0x544a842007902800
===
/sys/devices/pci0000:40/0000:40:03.0/0000:42:00.0/host2/scsi_host/host2/host_sas
_address
0x544a84200792ce00