I have found what I wanted (changing retention days) but that was through the forums rather than my being able to locate the option myself, so just wondering where the documentation for the above is kept, Veeam.Backup.Model.CDomBackupStorageOptions in this case for retention days
This is most comprehensive and detailed documentation regarding our PS snap-in.
As to different internal properties, methods, etc., those are typically not documented due to their changeable nature (might be modified with every product release, update, etc.). Thus, it's more or less trial and error approach of correlating PS properties with their GUI analogues.
Fortunately, a lot of them have self-descriptive names.
no worries.. as i say, i have working what i was trying to do, but i dont like just cutting and pasting powershell commands without knowing where they came from in terms of learning how it hangs together but i guess at this point i will just have to accept that some things are just black magic
The general approach to change job settings is the following:
1) You get particular job(s) settings of which you want to modify. (Get-VBRJob)
2) Assign it to a variable. ($Job)
3) Get its options. ($Job.GetOptions())
4) Assign it to a variable. ($Options)
5) Working with the $Options variable, understand what specific settings need to be changed.
6) Specify new values for those.
7) Assign modified $Options variable to the $Job variable ($Job.SetOptions($Options)).