1) Netbackup agents and their licensing ?
http://www.symantec.com/business/products/licensing/index.jsp
2) Does separate license will be required for adding clients like UNIX (Solaris, Linux), Windows , Databases (Oracle, Sybase etc) , ESX (Vmware)
for windows and unix normal standard client is fine, For databases seperate application client license is reqiuired, for ESX you require enterprise client.
3) like in my environment, i have 4 Oracle databases running on SUN E2900 system and only 1 license is purchased.
My query is that, if i want to run another database like SYBASE on same server, do i have to buy another license ? or per server license will be enough ?
yes, you need to buy another license for that application even though it is active in the same server which has database client for another application.
Another query related to databse is that, 4 database are running on Primary Site, and 1 system V890 is on DR site as a Standby, Does that V890 system will reqiure a separate NBU database License ? same case for MS-SQL.
yes, here license is based on application per single server, so two different applicaitons within single server, then two licenses are required.. in your case since DR is another physical box you require an paper license for that too.
4) If in NBU environment, i have a TAPE Library like SL500 with 4 drives and i want to add more drives ? whats in this scenario ?
license is based on tape drive, buy license for one more drive
5) Does a special License will be required for a single Tape library with NO Drive ?
good question, there cannot be a scenrio like a tape library without drive.. ha ha aha ha
Specially i want to know information about licensing in tape Library environment.
just check with your pre-sales guy. he shall claify this all...