About data migration during an online migration:
cw-ch is right, when you do a online migration package, Pulse does not migrate data ( .cub file are not migrated). For attributes it's different because attribute definition is stored .dimx file and attributes values is stored in .dimd.
During an online migration:
If the dimension has less elements than MaximumElements parameter value in Pulse.cfg (by default it is set to 5,000), then Pulse will create the dimension, create the elements and then populate the attributes.
If the dimension has more elements than MaximumElements value, the dimension will be created without any elements so attributes won't be migrated as-well.
About Security objects:
Pulse does not migrate security objects during online migration. There are many reasons for that, one of them is that it is very likely that the security between 2 instances is different. If you want to migrate security objects you'll have to use the offline mode.
To summarize what has been said let's take an example:
In tm1srv01, we have a Account dimension, with attributes (Description...) and there is an element security cube with a rule:
Let's migrate the Account dimension from tm1svr01 to tm1svr05:
We include only the Account dimension:
In the changes we can see that dimd and dimx will be created:
No dependencies are picked up:
Let's create both packages (Feeders, Views and subsets are included only on offline mode):
If you go to View Packages we have now 2 packages (OFFLINE and LIVE):
Let's execute the Live one on tm1svr05 instance:
Now if we check tm1svr05, we can see that Account dimension has been created and attributes has been populated:
Attributes and elements have been migrated because the Account dimension has less than 5,000 elements (default value of MaximumElements).
If we have a look at the OFFLINE package, we can see that the security objects have been included:
I hope this example helped to understand better how the migration works. If not feel free to reply to this post.