wwn of a linux hba

My problem is that I wanted to filter access on a raid array instead of doing it on the switch. I could login to the switch and figure out the linux hba's wwn (world-wide-name), but I thought there must be a way to get it from the linux machine directly.
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online resize of lvm filesystem on fibre channel or iscsi or similar when using multipath

I had a problem with a filesystem that was full on a vm. The vm's hard drive is just a lun on a fibre channel. So I resized the lun on the raid controller. The devices (/dev/sdx) for the drive noticed the new size after I did the usual scan and partprobe, but the multipath device didn't see the new size and was working off the old size. After some digging I found this page on how to get multipathd to notice the new size. I'll summarise here.
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