Like Dynamox said "devices can exist in a thin pool and be in a disabled state, but disabled devices are not available for extent allocation".  I used command line many times in similar situation where I enabled only the TDAT's that were in disabled state but never did enable on all. I am not sure about  options it will show if you try it through SMC.  The command line option to enable only the "disabled: devices is as follows:- symconfigure -sid 123 -cmd "enable dev XXXX:YYYY in pool Test_Pool type=thin;" commit  Where XXXX:YYYY is the device range for the disabled devices in the pool  I will not recommend doing enable on all the TDAT's in the pool.
We had disks added to our vmax and the ce created the datadevices and tdats. using SMC, I added the tdats into my thin pool (they were in disabled state to add). the thinpool shows status of 'balancing' but the devices I added are still reporting as 'disabled' and 'inactive'.Is this normal? or do I need to manually change the state to Enabled?
adding tdats to thin pool