SRDF meta volumes cannot be extended.  You will need to break the SRDF pairings (remove SRDF), extend the volumes independently, and then recreate the SRDF pairings.
Hello,    We have an SRDF/CE cluster using concatenated (R1 and R2) meta-volumes .  Is there an online procedure to extend these volumes? The SRC/CE cluster runs Windows 2008 R2  thanks in advance,  Francis  
Extend concatenated SRDF meta?