how to migrate svn directory

Hi, buddies,
     my team need to migrate our working svn directory from server A to
another server B, is there any tool or suggestions?
I have rw right of A & B, and admin of server A/B is callable.
     we wannar migrate our code with change logs.

I tried to use hg-subversion to check out all the svn changes and push to
server B. I got a error message:
                        "abort: unable to operate on unrelated repository"

server A
|
|___Dir-0
|
|___Dir-1(migrate from here) +r +w
|
.
.
|___Dir-N

server B
|
|___Dir-0
|
|___Dir-1(migrate to here) +r +w
|
.
.
|___Dir-N

-- 
weyllor