Multi-threading is designed to improve backup performance while the database is running. This feature is enabled by default for online and offline backups in OpenEdge 13.0.

To disable multi-threading, specify -thread 0 on the command line when running the backup, as follows: 

probkup online newb testdb.bk -thread 0
Note: Changes to the -thread parameter do not persist. You must set -thread to 0 every time you want to disable multi-threading in the PROBKUP utility.
When the multi-threaded backup feature is enabled, you can use the -threadnum parameter to specify the number of threads the PROBKUP utility will create during the backup, with the maximum being twice the number of CPUs on the running system.

In the following example, -threadnum is unspecified, so the default value is used. The default value is equal to the number of CPUs on the system, with a maximum value of 6. In this example, the default value is 4 . The write buffer factor, which controls the amount of memory used to write data to buffers, defaults to 1024. 

probkup online testdb testdb.bk -com
...
Number of threads not specified. The default number of threads used is 4. (20669)
Write buffer factor (-wbf): 1024 (20786)
Backup has spawned 4 worker threads. (20857)
Backup will be compressed using ZSTD compression. (20279)
Compression level set to 3. (20280)

1079 active blocks out of 1098 blocks in testdb will be dumped. (6686)
256 BI blocks will be dumped. (6688)
Backup requires an estimated 6.2 MBytes of media. (9285)
Restore would require an estimated 1595 db blocks using 6.2 MBytes of media. (9286)
Backed up 1335 db blocks in 00:00:01
Wrote a total of 18 backup blocks using 2.4 MBytes of media. (13625)

Backup complete. (3740)

The following multi-threaded backup example shows how PROBKUP adjusts a specified thread number greater than the maximum number to be the maximum value. This example occurs on a system with four CPUs. Because the user sets -threadnum to more than twice the number of CPUs on the system, the utility resets the maximum number of threads to eight, which is twice the number of CPUs: 

probkup online newb testdb.bk -threadnum 50
...
Thread number specified exceeds the max/available CPUs. 
Maximum number of threads that will be used is 8. (20671)
Write buffer factor (-wbf): 1024 (20786)
Backup has spawned 8 worker threads. (20857)

10596116 active blocks out of 10596147 blocks in testdb will be dumped. (6686)
256 BI blocks will be dumped. (6688)
Backup requires an estimated 89.9 GBytes of media. (9285)
Restore would require an estimated 1595 db blocks using 6.2 MBytes of media. (9286)
Backed up 10596372 db blocks in 00:05:20
Wrote a total of 311959 backup blocks using 80.9 GBytes of media. (13625)

Backup complete. (3740)

For more information on PROBKUP syntax and usage, see PROBKUP utility.