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Monday, May 20, 2013

Increase Cluster File System - CVM Cluster

In this post I would like to discuss and demonstrate about increasing the Cluster File System (CFS) in CVM environment.

    - The requirement is to increase the filesystem by 1TB.

As a best practice, in a CVM/CFS environment, volume should be grown on CVM master and file system should be grown on a CFS Primary. Please note that the CVM Master and the SF CFS node can be two different nodes.

Just off the topic, to know how to grow volume on CVM master & then grow the filesystem on CFS Primary -

To increase the size of the file system, execute the following on CVM master -

# vxassist –g shared_disk_group growto volume_name newlength

And then on CFS node, execute-

# fsadm –F vxfs –b newsize –r device_name mount_point

On other hand, if the system is both CVM master and CFS primary, then "vxresize" command could be executed on the system without any issues.

The above mentioned statement is true below VERITAS version 3.5 but from and above VERITAS version 3.5 vxresize can be run on any nodes within the cluster provided that attribute named 'HacliUserLevel' is set to value "COMMANDROOT". The default value of this attribute is 'NONE' which prevents user to run vxresize command from all the nodes in the cluster.

In my case it is set to "COMMANDROOT"

# /opt/VRTSvcs/bin/haclus -display | grep Hacli
HacliUserLevel         COMMANDROOT

But if the value of attribute 'HacliUserLevel' is set to "NONE" then below is method can be used to change the value.

To change the value to COMMANDROOT, run:

# /opt/VRTSvcs/bin/haconf -makerw
# /opt/VRTSvcs/bin/haclus -modify HacliUserLevel COMMANDROOT
# /opt/VRTSvcs/bin/haconf -dump -makero

This change allows vxresize to call hacli command, which then allows any command to be run on any system within the cluster.

Okay, back to our requirement -

So first let's find out the CFS primary node -

# fsclustadm -v showprimary /u01-zz/oradata

Now let's find out the master CVM node in the cluster by -

# vxdctl -c mode
mode: enabled: cluster active - SLAVE
master: XXXXX

Now that I need to increase the filesystem by 1TB hence I'm checking if disk group has enough space in it.

# vxassist -g dde1ZZGO0 maxsize
Maximum volume size: 2136743936 (1043332Mb)

Well, we have enough space available under disk group dde1ZZGO0.

Let increase the FS by 1TB now -

# vxresize -b -F vxfs -g dde1ZZGO0 ZZGO0_v0 +1000g


# df -kh /u01-zz/oradata
Filesystem             size   used  avail capacity  Mounted on
                       5.0T   5.0T    17G   100%    /u01-zz/oradata


# df -kh /u01-zz/oradata
Filesystem             size   used  avail capacity  Mounted on
                       6.0T   5.0T   954G    85%    /u01-zz/oradata

Good learning about attribute HacliUserLevel, isn't it?