cannot create tree quota

I have 2 NSG40 repl v2.

Both have sym_std pool which is almost full have only 80GB available space on source and 200GB available on target ( potential storage is bit more and AVM is avalable)

Now therew was already an FS replicating fs_test_001 between the two. FS is 90% full.

I extended the above fs_test_001 by 1024MB  successfully, both source and destianation are at same size.

I am trying to create now a tree quota : /abc/xyz/fudge with hard limit of 10MB and it has just stuck giving the below error:

I don't know whats causing this as 10MB of data is still ok, i guess.

Another quesiton : What is the minimum threshold i should keep in a FS or SAvPool before issues start like backup fails etc.

Severity:	Warning
Brief Description:	Slot 2: Source=275_00029010_0180_467_00029010_0182(alias=Repln_fs_test_001), starting transfer. Destination has no space available. Source is retrying.
Full Description:	The system tried to start the data transfer but there was not enough object space or SavVol space available on the destination side.
Recommended Action:	Ensure that the destination object and SavVol space is extendable on the destination side using the nas_fs -info -all command. The system will start data transfer when space becomes available.
Message ID:	86174859288

Thanks for your help.