Tape configuration guidelines

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Review these guidelines before attempting backup operations to tape storage.

Preparing for backup to tape

Windows operating systemsLinux operating systemsBefore attempting a backup to tape, these parameters must be set on the IBM Storage Protect server for your tape backups:
  1. Define the management class:
    define mgmtclass <domain name> <policy set name> <mgmtclass name>
    For example:
    define mgmtclass tape tape DISK
  2. Define the copy group:
    define copygroup <domain name> <policy set name> <mgmtclass name>
destination=<stgpool name>
    For example:
    define copygroup tape tape DISK destination=Diskpool
  3. Activate the policy set:
    activate policyset <domain name> <policy set name>
    For example:
    activate policyset tape tape
When configuring backup to physical tape, there are additional configuration requirements. You must always keep IBM Storage Protect metadata (control files) on disk and the actual VM backup data on tape.
  • Use the VMMC option to store the VMware backups (and VMware control files) with a management class other than the default management class.
  • Use the VMCTLMC option to specify the management class to use specifically for VMware control files during VMware backups. The management class that you specify overrides the default management class. It also overrides the management class specified by the VMMC option. The VMCTLMC management class must specify a disk storage pool, with no migration to tape.
  • The VMMC option is always used to control the retention on VM backups. This option applies to both disk and tape configurations. VMCTLMC is not used for the retention of the control files. The control and data files are part of the same grouping and are expired together based on the retention policy of the VMMC option. When both options are set, VMMC is used for data files and VMCTLMC is used for control files.
Restriction: Restore operations that use storage agents in LAN-free configurations might restore files from a copy storage pool even though the data might be retrievable from a primary storage pool. This might happen if the restore request is for a specific file, or the restore request is not using the no-query method, and the primary copy of the file is stored in a storage pool that is not accessible through a LAN-free path. This can also affect non-restore situations such as Data Protection for VMware backup operations. In a Data Protection for VMware environment, the preferred storage method for VM control files is disk, such that a mount is not needed to restore the file during the incremental backup process. These VM control files not only need to be placed on disk, but they should not be backed up to a copy storage pool that is available through a LAN-free path. If they are, a tape mount will be used to restore the files during a LAN-free incremental backup from a Data Protection for VMware client.
If the IBM Storage Protect server environment uses disk to tape migration, consider the following guidelines before migrating:
  • Set the disk storage pool MIGDELAY to a value that supports most mount requests to be satisfied from disk. Typical usage patterns indicate that a high percentage of individual file recoveries occurs within few days. For example, usually 3 - 5 days from the time a file was last modified. Therefore, consider keeping data on disk for this brief period to optimize recovery operations.

    In addition, if client side deduplication is being used with the disk storage pool, set the MIGDELAY option that accommodates frequent full VM backups. Do not migrate data from the deduplicated storage pool to tape until at least two full backups are completed for a VM. When data is moved to tape, it is no longer deduplicated. For example, if full backups are run weekly, consider setting MIGDELAY to a value of at least 10 days. This setting ensures that each full backup identifies and uses duplicate data from the previous backup before being moved to tape.

  • Use a device class file storage pool rather than a DISK device class storage pool. A typical value for a volume size, specified by a device class MAXCAPACITY parameter, would be 8 GB to 16 GB. For the associated storage pool, consider applying collocation by file space. Each VM that is backed up is represented as a separate file space in the IBM Storage Protect server. Collocating by file space saves the data from multiple incremental backups for a given VM in the same volume (disk file). When migration to tape occurs, collocation by file space locates multiple incremental backups for a given VM together on a physical tape.
Use the Settings dialog to set the Tape Mode value.

A backup operation becomes interrupted when a mount or instant restore operation requires the same tape storage simultaneously in use by the backup operation.