I have 2 gluster-servers(gfs0 192.168.190.56 and gfs1 192.168.190.57) to make a replication
the gfs0 have 1.3T datas  gfs1 is empty

[root@gfs0 tmp]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/xvda1            4.4G  3.5G  662M  85% /
tmpfs                 2.0G     0  2.0G   0% /dev/shm
/dev/xvdb             2.2T  1.3T  802G  62% /d/xvdb

[root@gfs2 tmp]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/xvda3            7.8G  1.8G  5.6G  25% /
tmpfs                 1.9G     0  1.9G   0% /dev/shm
/dev/xvda1            194M   28M  157M  15% /boot
/dev/xvdb             2.2T  124M  2.1T   1% /d/xvdb

i have created a volume named ot-gfs on gfs0 then i need to add another brick

glusterfs server  CentOS-6.0 x86_64 (replica 2) 2.6.32-220.el6.x86_6


[root@gfs0 tmp]#gluster volume  add-brick ot-gfs  replica 2 192.168.203.57:/d/xvdb/export/


[root@gfs0 tmp]# gluster volume info all

Volume Name: ot-gfs
Type: Replicate
Volume ID: 3268628f-4954-4e35-9bdc-28345655b643
Status: Started
Number of Bricks: 1 x 2 = 2
Transport-type: tcp
Bricks:
Brick1: 192.168.190.56:/d/xvdb/export
Brick2: 192.168.190.57:/d/xvdb/export
Options Reconfigured:
cluster.self-heal-daemon: off


finally the gfs0  cpu load is very high