The BAR_MAX_BACKUP parameter specifies the maximum number of parallel processes that are allowed for each onbar command. Although the database server default value for BAR_MAX_BACKUP is 4, the onconfig.std value is 0. If you set BAR_MAX_BACKUP to 0, the system creates as many onbar processes as needed. The number of onbar processes is limited only by the number of storage spaces or the amount of memory available to the database server, whichever is less.
If you have a large number of storage spaces and set BAR_MAX_BACKUP to 0, you may encounter an onbar timeout followed by a failure.
You have 40 dbspaces and set BAR_MAX_BACKUP to 0 in the onconfig.std file.
This situation can fork 1 backup thread on each of the dbspaces, which would be 40 in total.
The result could be that some backup threads have to wait for the device and potentially reach the limit of BAR_TIMEOUT, which could lead to a stalled situation, followed by a failure of the onbar backup.