I have a phyiscal server which is divided into 5 Solaris LDOMS, now I need to give a domain role to each individual server, can anybody help me deciding the same. Each server performs different roles but One is having major role tobe performed. and some of them are also connected to DB server, which is on different physical server. please let me know, if anything else is required.
You need to allocate at least one domain as a dedicated control and service domain, and possibly even as an i/o domain too. This domain should not run any applications, but is used to control resources of the machine and provide a management console.
Then you will need to allocate your 5 guest LDOMs(domains) for applications. These guest domains share resources from the control domain. Their actual function(role) doesn't matter, as the different roles refer to how the server sees each machine, not how the user sees the machine.
You may have to do a bit more research to decide how to allocate resources optimally, depending on the system requirements for each domain.