rspo/spool_id/chunk is a SAP Parameter attribute which is used to control Determines the number of spool IDs reserved at one time information. This is available within R/3 SAP systems depending on the version and release level.
Below is the standard documentation available and a few details of the attributes values .
This parameter sets the number of spool number to be fetched
consecutiuvely from the number range Server. The default value is 100.
Maximum 15000 / number of spool work processes (with 32000 spool
numbers) 49500 / number of spool work processes (with 99000 spool
numbers)
Recommendations
Do not set higher than 768 (with 32000) or 2414 (with 99000). In special
cases, larger values can be set. This has to be decided on a
case-by-case basis.
See SAP Parameter Documentation for full SAP documentation for this profile parameter.