rebalance failure may happen during etimedout errors

Enviroment:
8 nodes centos 6.2 64-bit (each has 32 GB RAM and SSD )
1:10.6.2.42
2:10.6.2.43
3:10.6.2.44
4:10.6.2.45
5:10.6.2.66
6:10.6.2.68
7:10.6.2.69

8:10.6.2.89

Setup:
Create a 7 nodes cluster with couchbase server 2.5.0-1024
Create 2 buckets:
sasl-1 with 1 replica, 1 doc with 1 view
sasl-2 with 2 replica, 1 doc with 1 view

Load items with size from 128 bytes to 512 bytes into cluster.
Load dgm until active resident got 90% at each bucket.
Then test
Warmup test without load: passed
Warmup test with load: passed
Add a node (89) and rebalance: failed with error

Rebalance exited with reason {unexpected_exit,
{'EXIT',<0.7063.546>,
{badmatch,
[{'EXIT',
badmatch,{error,etimedout,

}}]}}}
ns_orchestrator002 ns_1@10.6.2.42 16:10:48 - Thu Jan 9, 2014
<0.6159.546> exited with {unexpected_exit,
{'EXIT',<0.7063.546>,
{badmatch,
[{'EXIT',
badmatch,{error,etimedout,

}}]}}} ns_vbucket_mover000 ns_1@10.6.2.42 16:10:37 - Thu Jan 9, 2014
Bucket "sasl-2" rebalance does not seem to be swap rebalance

After a while, tried to rebalance again. It's still failed with same error

I will try rebalance one more time and update result.