Scanning for new LUNs on Linux servers

   

# ls /sys/class/fc_host

 host0  host1  host2  host3


 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

 

And in other cases I use the following script to prod the sysfs scan and issue_lip entries directly:

 

 #!/bin/bash

SLEEP_INTERVAL=300

echo "Scanning all fibre channel host adapters"

for i in `ls /sys/class/fc_host`
do
    echo "Rescanning /sys/class/fc_host/${i}:"

    echo "  Issuing a loop initialization on ${i}:" 
    echo "1" > /sys/class/fc_host/${i}/issue_lip

    echo "  Scanning ${i} for new devices:"
    echo "- - -" > "/sys/class/scsi_host/${i}/scan"

    echo "Sleeping for ${SLEEP_INTERVAL} seconds"
    sleep ${SLEEP_INTERVAL}
done
 

=================


1) Check the newly assign LUN using below command and compare it using with our backup.


# multipath –ll

-------------------------------------------------------

mpath4 (36006016069502200b2fbd50e3173e011) dm-4 DGC,RAID 5

[size=400G][features=1 queue_if_no_path][hwhandler=1 emc][rw]

\_ round-robin 0 [prio=2][active]

 \_ 3:0:0:4 sdf 8:80   [active][ready]

 \_ 3:0:2:4 sdr 65:16  [active][ready]

\_ round-robin 0 [prio=0][enabled]

 \_ 3:0:1:4 sdl 8:176  [active][ready]

 \_ 3:0:3:4 sdx 65:112 [active][ready]

-------------------------------------------------------------------

In this case mpath4 is newly assign LUN, So continue to do the activity.
 

2)  Create the partition as below.


# fdisk /dev/mapper/mpath4

n

8e

# partprobe /dev/mapper/mpath4*

 
6) Check the newly created partition using below command.

 
# pvs

---------------------------------------------------------

PV                   VG         Fmt  Attr PSize    PFree

  /dev/dm-5            VolGroup01 lvm2 a-   1016.00M    0

  /dev/dm-6            VolGroup01 lvm2 a-     19.99G    0

  /dev/dm-7            VolGroup01 lvm2 a-    399.99G    0

  /dev/dm-8            VolGroup01 lvm2 a-     69.99G    0

  /dev/mapper/mpath4p1 VolGroup01 lvm2 a-    100.00G 4.00M

  /dev/sda6            VolGroup00 lvm2 a-    109.88G    0

--------------------------------------------------------------------------------

# pvcreate /dev/mapper/mpath4p1

 

# vgs

-----------------------------------------------------------------------------

VG         #PV #LV #SN Attr   VSize   VFree 

  VolGroup00   1   4   0 wz--n- 110.47G  56.56G

  VolGroup01   6   4   0 wz--n- 591.96G 200.00M

-------------------------------------------------------------------

 
# vgextend    VolGroup01   /dev/mapper/mpath4p1

# lvs

---------------------------------------------------------

LV          VG         Attr   LSize   Origin Snap%  Move Log Copy%  Convert

  backup      VolGroup00 -wi-a-  54.88G                                     

  home        VolGroup00 -wi-ao  10.00G                                     

  tmp         VolGroup00 -wi-ao   5.00G                                     

  usr         VolGroup00 -wi-ao  10.00G                                      

  var         VolGroup00 -wi-ao  30.00G                                     

  application VolGroup01 -wi-ao 569.96G                                     

  logs        VolGroup01 -wi-ao  20.00G                                      

  redo        VolGroup01 -wi-ao   1.00G 

--------------------------------------------------------------------------------

# lvextend -L +99.99G /dev/VolGroup01/application

# e2fsck –f /dev/VolGroup01/application

# resize2fs /dev/VolGroup01/application