Showing posts with label Storage. Show all posts
Showing posts with label Storage. Show all posts

Scan and Configure New LUNS on Redhat Linux (RHEL)

Found another useful thing on the web. This is the quick guide to rescan and configure newly added LUNS in Linux. 


To configure the newly added LUNS on RHEL:


# ls /sys/class/fc_host
 host0  host1  host2  host3

 fdisk -l 2>/dev/null | egrep '^Disk' | egrep -v 'dm-' | wc -l

 echo "1" > /sys/class/fc_host/host0/issue_lip

 echo "- - -" > /sys/class/scsi_host/host0/scan

 echo "1" > /sys/class/fc_host/host1/issue_lip

 echo "- - -" > /sys/class/scsi_host/host1/scan

 echo "1" > /sys/class/fc_host/host2/issue_lip

 echo "- - -" > /sys/class/scsi_host/host2/scan

 echo "1" > /sys/class/fc_host/host3/issue_lip

 echo "- - -" > /sys/class/scsi_host/host3/scan

 cat /proc/scsi/scsi | egrep -i 'Host:' | wc -l

 fdisk -l 2>/dev/null | egrep '^Disk' | egrep -v 'dm-' | wc -l

Alternatively, we can
run the re-scan-scsi script.

To scan new LUNs on Linux operating system which is using QLogic driver 

You need to find out driver proc file /proc/scsi/qlaXXX. 

For example on my system it is /proc/scsi/qla2300/0 

Once file is identified you need to type following command (login as the root
):
 
# echo "scsi-qlascan" > /proc/scsi/qla2300/0
 # cat /proc/scsi/qla2300/0

Now use the script rescan-scsi-bus.sh new LUN as a device. Run script as follows:
 
# ./rescan-scsi-bus.sh -l -w

The output of ls -l /sys/block/*/device should give you an idea about how each device is connected to the system. 

Differentiate local storage from SAN LUN - Quick HOWTO

This is the nice information which i found on web. Its very useful. In many scenarios we want to Differentiate with local disks from SAN LUN. 

In the example below orange is a virtual disk on an internal RAID controller, green is a CD-ROM connected via an IDE controller, and the rest are SAN-connected SCSI disks where "hostN" refers to the instance of the Host Bus Adapter they are connected to.

 # ls -l /sys/block/*/device

lrwxrwxrwx  1 root root 0 Sep 19 02:11 /sys/block/cciss!c0d0/device -> ../../devices/pci0000:00/0000:00:04.0/0000:0d:00.0/disk0 
lrwxrwxrwx  1 root root 0 Sep 19 02:11 /sys/block/hda/device -> ../../devices/pci0000:00/0000:00:1f.1/ide0/0.0
lrwxrwxrwx  1 root root 0 Sep 18 14:58 /sys/block/sda/device -> ../../devices/pci0000:00/0000:00:02.0/0000:13:00.0/host0/target0:0:0/0:0:0:0  
lrwxrwxrwx  1 root root 0 Sep 18 14:58 /sys/block/sdb/device -> ../../devices/pci0000:00/0000:00:02.0/0000:13:00.0/host0/target0:0:0/0:0:0:1 
lrwxrwxrwx  1 root root 0 Sep 18 14:58 /sys/block/sdc/device -> ../../devices/pci0000:00/0000:00:02.0/0000:13:00.0/host0/target0:0:0/0:0:0:64  
lrwxrwxrwx  1 root root 0 Sep 18 14:58 /sys/block/sdd/device -> ../../devices/pci0000:00/0000:00:02.0/0000:13:00.0/host0/target0:0:0/0:0:0:120  ...