Below query can be used to check Sybase replication disk space usage.

select 'Partition_Name'=substring(name,1,30),'Logical_Name'=substring(logical_name,1,10),id as 'Partition_Id',num_segs as 'Total_Segs',SUM(rs_segments.used_flag) as 'Used_Segs',
CASE
when status >=1 then "On-Line"
else "Off-Line"
END as State
from rs_diskpartitions join rs_segments
ON rs_diskpartitions.id=rs_segments.partition_id
group by rs_diskpartitions.id
order by rs_diskpartitions.id

Sample Output: