Reread partition table without rebooting?
Solution 1:
IMHO the most reliable/best answer is
partprobe /dev/sdX
Solution 2:
Rereading partition table information doesn't always work, but try
hdparm -z /dev/sda
or
sfdisk -R /dev/sda
If it works the values in /proc/partitions will change.
Solution 3:
On Centos7 :
According to https://access.redhat.com/solutions/199573
You should try :
partx -u <partition>
It worked for me.
Solution 4:
Note: Please assume that none of the partitions I am actually editing are opened, mounted or otherwise in use.
Given that assumption, the partition table can be successfully rescanned, and the issue won't arise. If you're getting that error, it's because the partition table is currently in use, and hence can't be re-scanned without creating inconsistencies.
Solution 5:
I (the original questioner) had a situation a few days ago when none of the other answers (including partprobe /dev/sdX, currently the accepted and highest-voted answer) worked. What did work, however, was this:
blockdev --rereadpt /dev/sdX
(I don't know why this worked and the others didn't, but I'm happy it did work, as it saved me a reboot on a busy server.)