Configuring SmartDisk deduplication for Oracle (4046103)

Date - 09/10
Affected Product Version - NVSD/NVBU
Affected Module & Version - NVSD 1.0 and above/ NVBU 8.5 and above
OS Version - ALL
Application Information - Oracle (All supported versions)

Description:
It appears that savesets created with our Oracle APM may insert header information (that appears random to SmartDisk) at small, regular intervals in the file. We’ve observed this interval to be 4K bytes in one case.

If you are interested in achieving dedupe within a single full backup for what is perceived to be a sparsely-populated or empty database, you can configure SmartDisk to use smaller chunks sizes.

To set up SmartDisk to use smaller chunk sizes, do the following:

1. Stop the SmartDisk instance

2. Edit the $IDP_ROOT/dedupe/etc/dedupe.cfg file

3. Change the "libchunk.avg_size" variable so that it is set to 1024 bytes or 2048 bytes.
(it's set to 16K bytes by default.)

4. After the change, the dedupe.cfg file should have this entry:

libchunk.avg_size = 1024

If you plan to use lower chunk sizes, make sure you have a machine with a significant amount of memory (baseline of 1 GB plus 0.4 GBytes of memory per terabyte to hold the larger dedupe index), fast processors, and a fast disk subsystem.