Archive size

Archive size affects backups, backfilling, frequency of shifting, and total number of points allowed.

To determine archive size, use the following guidelines:

• If you are backfilling data, see Backfilling management.

• Allow at least 2KB for each point in the system.

• An archive file cannot exceed 2TB. However, if your Data Archive server will have 50,000 points or fewer, then you can safely use the default value.

• If you have more than 50,000 points, run 64-bit Data Archive on a 64-bit Windows operating system and set the archive size to 4-8 KB times the total number of points, with the following consideration on memory resources.

  Select a size that allows at least two archive files to fit in the Windows File System Cache (FSC). At most times, Data Archive writes to and reads from the two or three most recent archive files. The FSC is capped at approximately 1GB on 32-bit systems, but can use all of the RAM on 64-bit systems. Therefore, a safe upper limit for archive files is 256 MB for 32-bit systems and (RAM ÷ 3) for 64-bit systems.

  Note: Many administrators size their archives based on a size that is convenient to use with their desired backup media. As a rule of thumb, set your Snapshot Event Queue to half of the archive size.

Archive size and point count limits

The archive size limits the number of points that can be created. No more than half of the archive records of a fixed archive can be primary records. To resolve this, before creating additional points, force the archives to shift into a larger archive. For details, see Force an archive shift.

Archive size and shift frequency

The larger the archive file, the less often an archive shift is necessary. To decide what archive size is optimal for your system, consider the following factors:

• Backup device

• Available disk space

• Average incoming data rate