How to change qdepth for Red Hat

The default Max Queue Depth setting is 32 for  Red Hat. You can change  it  to configure  /etc/modprobe.conf [RHEL 5] and  also add  new  config  file to /etc/modprobe.d/ [for  RHEL 6].

In some particular situations, you should change this to a higher or lower value. It depends on your storage vendor. Please before set it to ask your vendor what is the recommended value for the storage side.

Check your Red Hat  version and also  qdepth value:

#cat /etc/redhat-release
Red Hat Enterprise Linux Server release 6.6 (Santiago)[/shell]

[shell]# modinfo qla2xxx | grep ql2xmaxqdepth
parm: ql2xmaxqdepth:Maximum queue depth to report for target devices. (int)

# cat /sys/module/qla2xxx/parameters/ql2xmaxqdepth


Just add this configuration to  /etc/modprobe.conf file and restart the server.

#vi  /etc/modprobe.conf[/shell]

alias scsi_hostadapter1 qla2xxx
options qla2xxx ql2xmaxqdepth=16


Step 1:Create  a config file under modprobe.d

Changing qdepth on Red Hat  6 is a bit complicated but very clear steps. First off all you need to re-create  "initramfs" file. Before start operation takes a  backup of initramfs.


# vi  /etc/modprobe.d/qlx.conf
options qla2xxx ql2xmaxqdepth=16

Step 2:Copy current  initramfs and  create new  one


# ls -ld /boot/initramfs-$(uname -r).img
-rw-------. 1 root root 24217151 Mar 2 09:24 /boot/initramfs-2.6.32-573.18.1.el6.x86_64.img

# cp /boot/initramfs-$(uname -r).img /boot/initramfs-$(uname -r).img.$(date +%m-%d-%H%M%S).bak

Re-create new  initramfs file

# dracut -f -v

The last line 'll be same as  like  this which  depends on your kernel version

I: Wrote /boot/initramfs-2.6.32-573.18.1.el6.x86_64.img
I: -rw-------. 1 root root 24216130 Mar 2 11:21 /boot/initramfs-2.6.32-573.18.1.el6.x86_64.img

***If you are in a kernel which different from initrd version you should run dracut command with kernel option.

#dracut -f /boot/initramfs-2.6.32-220.7.1.el6.x86_64.img 2.6.32-220.7.1.el6.x86_64

Step 3: Restart Server and  check new  qdepth

#shudown -r  now

# cat /sys/module/qla2xxx/parameters/ql2xmaxqdepth


I'm a IT Infrastructure and Operations Architect with extensive experience and administration skills and works for Turk Telekom. I provide hardware and software support for the IT Infrastructure and Operations tasks.

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