Storage capacity requirements

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With IBM Storage Protect Snapshot, you need storage space for the product installation, space to store IBM Storage Protect Snapshot metadata, and space on the storage device for the snapshot backups.

Product installation

The space that you need for the product installation of IBM Storage Protect Snapshot depends on the components that are installed. Space requirements also depend on required maintenance updates and required operating systems, applications, and other software currency support.

When you plan a product installation, the following components is required depending on the data that you want to protect:
  • Microsoft Management Console (MMC) and the VSS Requestor are required components. You install MMC when you install the software by running the setupfcm.exe file. The VSS Requestor is automatically installed for all installations.
IBM Storage Protect Snapshot metadata

IBM Storage Protect Snapshot uses disk space to store product metadata that tracks and manages snapshots (point-in-time consistent copies of application data).

The amount of space that is required is directly proportionate to the number of snapshots that you maintain on the system. For each snapshot that you plan to retain on the system, ensure that at least 1 MB of free disk space is available to store the metadata.

The amount of disk space that is required to store metadata depends on the configuration of your environment.
Configuration with only IBM Storage Protect Snapshot
If you are protecting Microsoft Exchange Server data, IBM Storage Protect Snapshot retains mailbox history information in the metadata to support individual mailbox restore (IMR) processing. The amount of space that is required to store the metadata is proportionate to the number of mailboxes and log files in the entire organization. For each user mailbox in an organization, ensure that at least 50 KB of disk space is available to store the metadata.
Configuration with IBM Storage Protect and IBM Storage Protect Snapshot
If you are protecting Exchange Server data, IBM Storage Protect Snapshot retains the mailbox history information that is stored on the IBM Storage Protect server. In this configuration, no disk space is required for IBM Storage Protect Snapshot.
Snapshot copies

Snapshot copies of application data require the most storage space. The amount of space that is required depends on the following factors:

  • The VSS provider that you use and the configuration of the VSS provider
  • The total size of all source volumes that contain the application data
  • The rate at which the source volumes are altered after a snapshot is taken

Full snapshots are the standard type of FlashCopy® snapshot. On SAN Volume Controller, DS8000®, and Storwize® V7000 storage devices, full snapshot copies require the same amount of space as the corresponding source volumes. However, with the Windows System VSS provider, space-efficient copies on SAN Volume Controller and the XIV® system initially require space for only the metadata. The space requirement for snapshot copies increases with every volume block that changes on the corresponding source volume. As more source volume blocks change, more space is required for the target volumes that represent a snapshot copy of those applications.