Backup procedure with SOBAR

This section provides a detailed example of the backup procedure that is used with SOBAR.

Throughout these procedures, the sample file system that is used is called smallfs. Where appropriate, replace this value with your file system name.

  1. Back up the cluster configuration information.

    The cluster configuration must be backed up by the administrator. The minimum cluster configuration information that is needed is: IP addresses, node names, roles, quorum and server roles, cluster-wide configuration settings from mmchconfig, cluster manager node roles, remote shell configuration, mutual ssh and rsh authentication setup, and the cluster UID. Complete configuration information can be found in the mmsdrfs file and CCR.

  2. Preserve disk configuration information.

    Disk configuration must also be preserved to recover a file system. The basic disk configuration information needed, for a backup that is intended for disaster recovery, is the number of disk volumes that were previously available and the sizes of those volumes. To recover from a complete file system loss, at least as much disk space as was previously available is needed for restoration. It is feasible to restore the image of a file system on to replacement disks only when the disk volumes available are of similar sizes. This enables to restore data to the new disks. At a minimum, the following disk configuration information is needed:

    • Disk device names
    • Disk device sizes
    • The number of disk volumes
    • NSD server configuration
    • Disk RAID configurations
    • Failure group designations
    • The mmsdrfs file contents
  3. Back up the GPFS file system configuration information.
    In addition to the disks, the file system that is built on those volumes has configuration information that can be captured by using the mmbackupconfig command. This information includes block size, replication factors, number and size of disks, storage pool layout, file sets and junction points, policy rules, quota information, and a number of other file system attributes. The file system configuration information can be backed up into a single file by using a command similar to the following example:
    mmbackupconfig smallfs -o /tmp/smallfs.bkpcfg.out925
    Ensure to copy the temporary file that is created by the preceding command to a secure location so that it can be retrieved and used during a disaster recovery.
  4. Pre-migrate all newer file data into secondary storage.
    File contents in a space-managed GPFS reside in secondary storage that is managed by IBM Storage Protect. If IBM Storage Protect, disk and tape pools typically hold the offline images of migrated files. IBM Storage Protect can also be used to pre-migrate all newer file data into secondary storage, so that all files have either a migrated or pre-migrated status (XATTR) recorded, and their current contents are copied or updated into the secondary storage. The IBM Storage Protect command dsmmigrate can be used as follows:
    dsmmigrate -Premigrate -Recursive /smallfs
    Optionally check the status of the files that were pre-migrated with the previous command, use the following command:
    dsmls /smallfs/*
  5. Create a global snapshot of the live file system, to provide a quiescent image for image backup, by using a command similar to the following:
    mmcrsnapshot smallfs smallfssnap
  6. Choose a staging area in which to save the GPFS metadata image files.

    The image backup process stores each piece of the partial file system image backup in its own file in the shared work directory that is typically used by policy runs. These files can become large depending on the number of files in the file system. Also, because the file system that is holding this shared directory must be accessible to every node that is participating in the parallel backup task, it might also be a GPFS file system. It is imperative that the staging directories chosen are accessible to both the tsapolicy archiver process and the IBM Storage Protect Backup-Archive client. This staging directory is specified with the -g option of the mmimgbackup command.

  7. Back up the file system image.
    The following command backs up an image of the GPFS metadata from the file system by using a parallel policy that is run with the default IBM Storage Protect backup client to back up the file system metadata image:
    mmimgbackup smallfs -S smallfssnap -g /u/user/backup -N aixnodes

    The metadata of the file system, the directories, inodes, attributes, symlinks, and so on, are all captured in parallel by using the archive module extension feature of the mmapplypolicy command. After completing the parallel execution of the policy-driven archiving process, a collection of image files in this format will remain. These image files are gathered by the mmimgbackup command and archived to IBM Storage Protect automatically.

    If you are using the -N nodes option, it is a good idea to use the same operating system when running mmimgbackup. Also, the directory that was created with the -g GlobalWorkDirectory option to store the image files must exist and must be accessible from all the nodes that are specified.

  8. After the image backup is complete, delete the snapshot that is used for backup with the following command:
    mmdelsnapshot smallfs smallfssnap