Do partitions needed to be unmounted when resizing a partition?

I have this article http://www.centos.org/docs/5/html/5.2/Deployment_Guide/s2-disk-storage-parted-resize-part.html which is not clear to me.

And also someone told me that swap space does not need to be disable if it is before the partition to resize.

Modifications: This is the related question extend size of partition. I am resizing a partition to add the extra/unallocated 1500GB disk space on the same disk. And would be better not to do it with lvm if possible.

I hope someone would enlighten me. Thanks

Line one of the linked article is pretty clear to me:

Do not attempt to resize a partition on a device that is in use.

I think that makes it fairly clear that the CentOS wiki feels it needs to be unmounted ( in addition, the instructions recommend that you boot to rescue mode, which will effectively unmount all the partitions).

Edit: I understand from your other question that you propose to extend /dev/sda3, which is your root partition (which is, incidentally, where the OS is). As I understand it, online positive resizing (ie, resizing to expand a partition, without unmounting it) is supported for ext3 filesystems, but if you're going to try that, make sure you have excellent backups first, and that you've tested and documented your restore procedure.