To change Unavailable to Readonly or Readwrite.

From each server run this command to get the unavailable or readonly (tapes and disk volumes) 

i.e., Relbk1, Relbk2 and Relbk2-2: -

select volume_name,access from volumes where access='UNAVAILABLE' or access='READONLY'

then ckeck the each volume by quering and format=detail

q volume S0XXXXL3 F=D

///check if any readwrite errors or readonly errors.

tsm: RELBK1> 

SxxxxxL3               UNAVAILABLE       

SxxxxxL3               READONLY           

SxxxxxL3               UNAVAILABLE       

SxxxxxL3               UNAVAILABLE       

SxxxxxL3               UNAVAILABLE       

SxxxxxL3               UNAVAILABLE       

To update the volume from unavailable to readwrite.

UPDATE VOLUME SxxxxxL3 Access=readwrite whereaccess=UNAVAILABLE