Hi @Anantha123 ...
1). on DMC, you can get the index size details.
2). Using dbinspect command you can get the index size
| dbinspect index=myindex | eval GB=sizeOnDiskMB/1024 | stat sum(GB)
3). rest command
| rest /services/data/indexes | stats values(currentDBSizeMB) by title
4) eventcount command:
| eventcount summarize=false index=* report_size=true | eval GB=(size_bytes/1024)/1024/1024 | stats sum(GB) by index, server
5) collect command: (not sure of this... pls test this one)
|collect index=myindex