There are situations when IBM Spectrum Scale needs to be uninstalled. Here a step by step guide for doing this.
What is IBM Spectrum Scale
IBM's clustered file system that provides parallel data access from multiple nodes was branded as Spectrum Scale. It is now re-branded as IBM Storage Scale.
To know more about IBM Spectrum Scale, please visit https://www.ibm.com/docs/en/storage-scale/5.1.8?topic=overview-storage-scale
IBM Spectrum Scale is a file system. But not an ordinary file system running locally on a single computer. Spectrum Scale runs on multiple computers. These computers together make a cluster. They are known as the nodes of the cluster. Some of the nodes are arranged access to a storage that is present in the network. The storage is available to the nodes in the form of Network Shared Disks (NSDs). The available NSDs are used to create file system. Customers use the file system to store and access data, via NFS, CIFS, or object protocols.
IBM Spectrum Scale provides concurrent high-speed file access. Applications that access the data may be running on multiple systems and accessing the data in parallel.
A Spectrum Scale cluster may consist of 1 to 56 nodes. The nodes could be assigned the roles of quorum nodes and data nodes.
Before we begin
A spectrum scale cluster consists of one or more nodes. At every node of the cluster, the spectrum scale packages are installed. Apart from the packages, some files and directories are present which are required for the functioning of the node. This procedure is of uninstalling Spectrum Scale from a single node.
Pre-checks
Before uninstalling spectrum scale from a node, please check :
(a) Is the node part of a spectrum scale cluster? Run command mmlscluster to check this.
(b) Does the node have NSDs? Are the NSDs local to the node or are they shared NSDs? Are any of the NSDs being used? Run command mmlsnsd to check these.
(c) Are any spectrum scale file systems mounted at this node? Run command mmlsmount to check this.
Uninstallation Procedure
1. If the node has any file systems mounted, then all file systems must be unmounted from this node. Unmount all file systems from the node by running command mmumount all
Verify that the node does not have any spectrum scale file system mounted by running command mmlsmount all
2. If the node has shared NSDs, then all shared NSDs should be removed. In this case, please think for a while "why are we really uninstalling spectrum scale from this node? Is this really necessary?" If answer is affirmative, then please proceed to remove all the shared NSDs. For doing so, the shared NSDs must be in unused state. Please check if any of the shared NSDs are being used in any spectrum scale file system(s). If yes, then remove the NSDs from the file system(s) using command mmdeldisk
Verify that the NSDs in question are in unused state by running command mmlsnsd
Delete the NSDs by running command mmdelnsd
Verify that the NSDs in question are deleted by running command mmlsnsd
3. If the node has local NSDs, then all local NSDs should be removed. Please check if any of the local NSDs are being used in any spectrum scale file system(s). If yes, then remove the NSDs from the file system(s) using command mmdeldisk
Verify that the NSDs in question are in unused state by running command mmlsnsd
Delete the NSDs by running command mmdelnsd
Verify that the NSDs in question are deleted by running command mmlsnsd
4. If the node is part of a spectrum scale cluster, then it should be removed from the cluster. To do so, login to any other node in the cluster, and run command mmdelnode
Verify that the node is not part of the cluster by running command mmlscluster
5. If the spectrum scale software is running at the node, stop it by running command mmshutdown
6. Remove all spectrum scale packages that are currently installed.
Some of the spectrum scale packages have dependencies, and can not be removed individually. So all spectrum scale packages should be removed together using a single command.
On a node running Red Hat Enterprise Linux, you could run `rpm -qa | grep gpfs` to get a list of spectrum scale packages that are currently installed. For example :
# rpm -qa | grep gpfs
gpfs.base-5.1.8-2.230821.114705.ppc64le
gpfs.adv-5.1.8-2.230821.114705.ppc64le
gpfs.license.dev-5.1.8-2.230821.114705.ppc64le
gpfs.gpl-5.1.8-2.230821.114705.noarch
gpfs.crypto-5.1.8-2.230821.114705.ppc64le
gpfs.compression-5.1.8-2.230821.114705.ppc64le
gpfs.msg.en_US-5.1.8-2.230821.114705.noarch
gpfs.gskit-8.0.55-19.1.ppc64le
gpfs.base-debuginfo-5.1.8-2.230821.114705.ppc64le
gpfs.docs-5.1.8-2.230821.114705.noarch
#
Remove the packages by running command `rpm -e package_name`. For example :
# rpm -e gpfs.base-5.1.8-2.230821.114705.ppc64le gpfs.adv-5.1.8-2.230821.114705.ppc64le gpfs.license.dev-5.1.8-2.230821.114705.ppc64le gpf
s.gpl-5.1.8-2.230821.114705.noarch gpfs.crypto-5.1.8-2.230821.114705.ppc64le gpfs.compression-5.1.8-2.230821.114705.ppc64le gpfs.msg.en_US-5.1.8-2.230821.114705.noarch gpfs.gskit-8.0.55-19.1.ppc64le gpfs.base-debuginfo-5.1.8-2.230821.114705.ppc64le gpfs.docs-5.1.8-2.230821.114705.noarch
Verify that the packages are removed by running command `rpm -qa | grep gpfs`
On a node running Ubuntu, you could run `apt list | grep gpfs` to get a list of spectrum scale packages that are currently installed. For example :
# apt list | grep gpfs
gpfs.adv/now 5.1.8-2.230821.114705 ppc64el [installed,local]
gpfs.base-debuginfo/now 5.1.8-2.230821.114705 ppc64el [installed,local]
gpfs.base/now 5.1.8-2.230821.114705 ppc64el [installed,local]
gpfs.compression/now 5.1.8-2.230821.114705 ppc64el [installed,local]
gpfs.crypto/now 5.1.8-2.230821.114705 ppc64el [installed,local]
gpfs.docs/now 5.1.8-2.230821.114705 all [installed,local]
gpfs.gpl/now 5.1.8-2.230821.114705 all [installed,local]
gpfs.gskit/now 8.0.55-19.1 ppc64el [installed,local]
gpfs.license.dev/now 5.1.8-2.230821.114705 ppc64el [installed,local]
gpfs.msg.en-us/now 5.1.8-2.230821.114705 all [installed,local]
#
Remove the packages by running command `apt remove package_name`
For example :
# apt remove gpfs.adv gpfs.base-debuginfo gpfs.base gpfs.compression gpfs.crypto gpfs.docs gpfs.gpl gpfs.gskit gpfs.license.dev gpfs.msg.en-us
Verify that the packages are removed by running command `apt list | grep gpfs`. For example :
# apt list | grep gpfs
gpfs.adv/now 5.1.8-2.230821.114705 ppc64el [residual-config]
gpfs.base/now 5.1.8-2.230821.114705 ppc64el [residual-config]
gpfs.compression/now 5.1.8-2.230821.114705 ppc64el [residual-config]
gpfs.crypto/now 5.1.8-2.230821.114705 ppc64el [residual-config]
gpfs.docs/now 5.1.8-2.230821.114705 all [residual-config]
gpfs.gpl/now 5.1.8-2.230821.114705 all [residual-config]
gpfs.gskit/now 8.0.55-19.1 ppc64el [residual-config]
gpfs.license.dev/now 5.1.8-2.230821.114705 ppc64el [residual-config]
gpfs.msg.en-us/now 5.1.8-2.230821.114705 all [residual-config]
#
Notice that the packages are not installed, but the configuration data still remains. To completely remove spectrum scale from the node, the configuration data needs to be removed as well. If this is not done, and later if this node needs to be added to another spectrum scale cluster, then that would be a problem, because of the existing old configuration.
7. Remove the /var/mmfs directory
# cd /var
# rm -rf mmfs/
8. Remove the /usr/lpp/mmfs directory
# cd /usr/lpp
# rm -rf mmfs/
9. Remove all files in the /var/adm/ras directory
# cd /var/adm/ras
# rm -rf *
10. Remove the /tmp/mmfs directory
# cd /tmp/
# rm -rf mmfs/
11. Reboot the node
This is how spectrum scale could be uninstalled from a node. If you want to uninstall spectrum scale from a cluster, then uninstall spectrum scale from all nodes of the cluster.
Summary
Uninstalling spectrum scale from a node is not simply removing the packages that are installed. There are some steps involved before removing the packages and after removing the packages. If the node is part of a cluster, then appropriate care should be taken so that the NSDs in use and the other nodes in the cluster are not affected.
