Completing the migration to a new level of IBM Spectrum Scale

It is a good idea to use the cluster for a while with the new level of IBM Spectrum Scale™ installed, until you are sure that you are ready to permanently migrate the cluster to the new level.

mmchconfig release=LATEST <parameterN=value> <parameterN+1=value>...

1. Verify that the SHA message digest and the cipherList configuration variable are set to valid values.
   Note:

   • The SHA message digest is a hash result that is generated by a cryptographic hash function.
   • The cipherList variable specifies the security mode for communications among nodes in the cluster and with nodes in other clusters. For more information, see mmchconfig command.
   Follow these steps:
   1. Display the current values by entering the following command. The listing shows both the command and example output:

      # mmauth show .
      Cluster name:        zounds.cluster (this cluster)
      Cipher list:         (none specified)
      SHA digest:          (undefined)
      File system access:  (all rw)

   2. If the value for the SHA digest is (undefined), follow these steps:
      1. Enter the following command to generate a public/private key pair and an SHA message digest:

         mmauth genkey new

      2. Enter mmauth show . again and verify that the value for SHA digest is no longer (undefined).
   3. If the value for cipherList is (none specified) or EMPTY, do one of the following actions:
      • If you want a level of security in communications between nodes and with other clusters, follow these steps:
        1. Set cipherList to AUTHONLY or to a supported cipher:

           mmauth update . -l AUTHONLY

        2. Enter mmauth show . again and verify that the value for cipherList is no longer (none specified) or EMPTY.
      • If you do not want a level of security cluster communications, let cipherList remain set to (none specified) or EMPTY.
2. Enter the following command to migrate the cluster configuration data, migrate the file systems, and enable new functionality. You can add the parameters that are described in Table 1 to the command line:

   mmchconfig release=LATEST

   Note: If the mmconfig command fails with an error message that indicates that cipherlist is set to EMPTY, do one of the following actions:

   • If you want the cluster to run with a higher security mode than EMPTY, set cipherList to AUTHONLY or to a supported cipher:

     mmauth update . -l AUTHONLY

     Return to the first part of Step 2 and run the mmchconfig command as before.
   • If you want the cluster to continue with the security mode set to EMPTY, return to Step 2 and run the mmchconfig command with the additional parameter --accept-empty-cipherlist-security.
3. If you have not already done so, assign an appropriate GPFS license to each of the nodes in the cluster. See IBM Spectrum Scale license designation for a detailed description of the GPFS license types. To see what the minimum required GPFS license is for each of the nodes in the cluster, enter the following command:

   mmlslicense -L

   To assign a GPFS server license to the nodes that require it, enter the following command:

   mmchlicense server -N NodeList

   To assign a GPFS client license to the nodes that require it, enter:

   mmchlicense client -N NodeList

4. Enable backward-compatible format changes or migrate all file systems to the latest metadata format changes.
   Attention: Before you continue with this step, it is important to understand the differences between mmchfs -V compat and mmchfs -V full:

   • If you enter mmchfs -V compat, only changes that are backward compatible with GPFS 3.5 are enabled. Nodes in remote clusters that are running GPFS 3.5 will still be able to mount the file system. Nodes running GPFS 3.4 or earlier will no longer be able to mount the file system.
   • If you enter mmchfs -V full, all new functions that require different on-disk data structures are enabled. Nodes in remote clusters that run an older GPFS version will no longer be able to mount the file system. If any nodes that run an older GPFS version have mounted the file system at the time this command is entered, the mmchfs command fails. This consideration might also apply to minor releases within the same major release. For example, release 4.1.0.x and release 4.1.1.x might have different metadata formats.
   To enable backward-compatible format changes, enter the following command:

   mmchfs FileSystem -V compat

   To migrate all file systems to the latest metadata format changes, enter the following command:

   mmchfs FileSystem -V full

   Certain new file system features might require more processing that cannot be handled by the mmchfs -V command alone. To fully activate such features, in addition to mmchfs -V, you must also run the mmmigratefs command. An example of such a feature is enabling fast extended attributes for file systems older than GPFS 3.4.

   Note: The first mount of a file system after you run mmchfs -V might fail with a no-disk-space error. This situation might occur if the file system is relatively low on metadata disk space (10% or less free). If so, enter the command again. Typically the file system is mounted without a problem after the initial failed mount.
   To activate fast extended attributes, enter the following command:

   mmmigratefs FileSystem --fastea

5. If you use the mmbackup command to back up your file system and you have not done a full backup since GPFS 3.3 or later, a full backup might be necessary. For more information, see File systems backed up using GPFS 3.2 or earlier versions of mmbackup.