[CentOS] swap labeling annoyance

I just upgraded a blade server via rsync from another server. Rebuilt the initrd. It boots fine... except that it won't turn on the swap partition. Several times, I've made sure swap was off, then mkswap -L SWAP-sda3 /dev/sda3, but when I do swapon -L SWAP-sda3, it complains it can't find the device for the label.

The only thing I find while googling, other than redoing what I've done several times now, is an old bug from CentOS 4, 0001399, which affected *only* blade enclosures: the reporter says that all of his IBM blades were affected (this isn't an IBM). His workaround was to make an ext2 fs, label it, and turn that into swap.

Has anyone seen this recently, with 6.2?

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