I have an encrypted partition that I setup during install for CentOS 6 that I want to mount manually after boot. By default it prompts me for a password at boot time. I was able to get it to not prompt me for a password at boot by commenting the drive out from /etc/fstab and /etc/crypttab (although this is probably the wrong way to do it). I tried adding noauto to both the crypttab and fstab but that didn't seem to help. So I guess my question is a two-parter:
1) How do I properly disable an encrypted partition from mounting automatically on boot?
2) How do I manually mount the partition after boot?
For reference I've enclosed the relevant lines from my fstab and crypttab (as they were setup by default):
fstab:
/dev/mapper/luks-4fa25d53-0dcd-44ab-9f4d-bee5d6f90fce /sec ext4 defaults 1 2
crypttab:
luks-4fa25d53-0dcd-44ab-9f4d-bee5d6f90fce UUID=4fa25d53-0dcd-44ab-9f4d-bee5d6f90fce none
noauto
as the 4th field in your crypttab file. If it works I'll update my answer. The crypttab manpage, however, seems to indicate that the passphrase is always asked for at boot time.