Replace failed disks in MD3460

Hello,

I manages 6 OSTs. Each OST fills with 12 disks in 5 drawers and sets up as RAID 6 with 6 VG disk groups.
On 3 OSTs, i have 1 failed disk. From the MDSM gui, i can see the failed disk status is Degraded and has the red X.
My question is:

* I can have the OST up and running, while pulling out the drawer, remove the failed disk, install a new disk, push back the drawer.
Do i need to remove the SAS cable from the chassis?

* Then go back MDSM , check the Re-Check button to rerun the Recovery Guru, is it correct?
* Status of the disk will change from Degraded -> Operation in Progress -> Optimal, right?

I hope to answer your question soon so that i can start to replace our failed disks.
Thank you.