what happened to /dev/xvdd in my instance?
I am working on a script to handle data disks. So, I added a few data disks to my instance. Then I noticed that in listVolumes api output, the third data disk actually has a deviceid 4, instead of 3 as I would expect. Sure enough, in the guest OS, I see three data disks as /dev/xvdb, /dev/xvdc, and /dev/xvde. There is no device /dev/xvdd.
Why does CloudStack skip device /dev/xvdd? I have verified this behavior on both ACS versions 22.214.171.124 and 126.96.36.199.