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Server configuration
10 Dell EMC SC Series: Red Hat Enterprise Linux Best Practices | CML1031
For local-boot systems, it is recommended to unmount all SAN volumes and reload the module. The module
should be unloaded from memory before it is reloaded as shown in the following.
# modprobe –r qla2xxx
# modprobe qla2xxx
Replace qla2xxx with lpfc if working with Emulex hardware; SAN volumes can be remounted subsequently.
2.1.4 Rebuilding the initial ramdisk image
For configuration persistence, rebuild the initramfs-*.img file so that the new configurations are incorporated
during boot time. The following methods demonstrate rebuilding the initramfs-*.img file. It is recommended to
copy and back up the existing initramfs-*.img file before applying this procedure.
# cp /boot/initramfs-$(uname -r).img /boot/initramfs-$(uname -r).img.$(date
+%Y%m%d-%H%m)
# dracut --force #this replaces the existing version of the initramfs file
Ensure that the grub configuration file points to the correct initramfs-*.img file and reboot the system. Find
the grub configuration file in one of the following locations:
/boot/grub/grub.conf #RHEL 6 and older
/boot/grub2/grub.conf #RHEL 7 and newer
2.1.5 Verifying the parameters
To verify that the configuration changes have taken effect, examine the driver module parameter values in
their respective files.
• QLogic:
# cat /sys/module/qla2xxx/parameters/qlport_down_retry
# cat /sys/module/qla2xxx/parameters/ql2xmaxqdepth
• Emulex:
# cat /sys/module/lpfc/parameters/lpfc_devloss_tmo
# cat /sys/module/lpfc/parameters/lpfc_lun_queue_depth
# cat /sys/module/lpfc/parameters/lpfc_hba_queue_depth
# cat /sys/class/scsi_host/hostX/lpfc_devloss_tmo #where X is the HBA no.
# cat /sys/class/scsi_host/hostX/lpfc_lun_queue_depth
# cat /sys/class/scsi_host/hostX/lpfc_hba_queue_depth