Ledger Set – we can combine multiple ledgers sharing the same COA and accounting calendar/period type.
After defined ledger set while closing the window system will run a request ‘General Ledger Accounting Setup Program’.
Create separate GL responsibility and attach this data access set through profile option ‘GL: Data Access Set’. When we configure this we can see consolidated results without performing consolidation. All the journals created in different ledger can be seen in this responsibility. We can run consolidated reports, trial balance, define FSG etc.
Data access set – we can combine multiple ledgers sharing the same COA and accounting calendar/period type. After defined when closing the window system will run a request ‘General Ledger Accounting Setup Program’.
Create separate GL responsibility and attach this data access set through profile option ‘GL: Data Access Set’. When we configure this we can see consolidated results without performing consolidation. All the journals created in different ledger can be seen in this responsibility. We can run consolidated reports, trial balance, define FSG etc.
Both looks similar then what is the difference

SL.NO	Particulars	Ledger Set	Data Access Set
1	Access set up type – Full ledger / Management segment value / Balancing segment value – we can define particular access	Not possible	Possible
2	Privilege – Read only access or read and write access	Not possible	Possible
3	Access setup type – when configuring management segment value / balancing segment value - can give access all the balancing segment values / management segment values or particular values -	Not possible	Possible
4	Access entries created in different ledger	Possible	Possible
5	Run standard or FSG reports for different ledgers	Possible	Possible

Ledger set can group only multiple ledgers defined and used whereas data access can combine multiple ledgers and / or multiple ledger sets.