How to configure device-mapper-multipath for EMC

At  this post I will add  a brief  explanation  of “how to configure RHEL native multipath(device-mapper-multipath) for EMC storage”.

Environment:

  • Red Hat Enterprise Linux 6-7
  • device-mapper-multipath (DM Multipath)
  • ECM  Clariion/VNX/Unity

Resolution: 

Multiple LUNs for RHEL 6.0 and later

Step 1: Check installed  HBA modules  with  lspci

Step 2:  Add scsi_mod.max_report_luns and  scsi_mod.max_luns to ‘kernel’ line  in  /etc/grub.conf and reboot system.

kernel /vmlinuz-2.6.32-573.12.1.el6.x86_64 ro root=/dev/mapper/vgroot-lvroot rd_NO_LUKS  KEYBOARDTYPE=pc KEYTABLE=trq LANG=en_US.UTF-8 rd_NO_MD rd_LVM_LV=vgroot/lvswap SYSFONT=latarcyrheb-sun16 crashkernel=128M rd_LVM_LV=vgroot/lvroot rd_NO_DM rhgb quiet  scsi_mod.max_report_luns=32768 scsi_mod.max_luns=32768

Step 3: Configure  multipath.conf  file

**Please check EMC Host Connectivity Guide for Linux for multipath configuration on  page  194-207. I added a  simple configuration sets  for  RHEL6.x and  RHEL7.x . But don’t forget to check your RHEL subversion  to find out spesific config sets. For example  RHEL 6.5  supports ALUA option. So maybe  you need to configure  multipathd  with  ALUA options. And also  RHEL 7.2 and  later has an option  “retain_attached_hw_handler” that can recognize PNR and ALUA automatically and does not need changes to the multipath.conf file.

Multiple LUNs for RHEL 7.0 and later

Step 1: Check installed  HBA modules  with  lspci

*So I’ll follow to define configuration for  QLogic. If  you have  Emulex  adapter and then  check  EMC Host Connectivity Guide for Linux.

Step 2:  Add scsi_mod.max_report_luns and  scsi_mod.max_luns to grub.conf

Step 3: Mkconfig  for  Grub

 

Step 4: Configure  multipath.conf  file

*Since RHEL7.2, the default stanza parameter retain_attached_hw_handler yes can recognize PNR and ALUA automatically and does not need changes to the multipath.conf file. However, the manual configuration of PNR and ALUA will still work.

 

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Abdurrahim

I'm a System Engineer with extensive experience and administration skills and works for Interbank Card Center Of Turkey.I provide hardware and software support for the following Unix/Linux and Windows platforms.(Oracle Solaris,HP-UX, Linux, IBM-AIX, Windows Servers)
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