Disk doesn't appear in blkid but does appear in lsblk

Question

When we do the following on a RHEL lab machine:

lsblk | grep sdd
sdd                8:48   0   1.8T  0 disk

we get the sdd disk, but when we do blkid as the following:

blkid  | grep sdd

we do not get any output.

We re-scan the disk as:

echo 1>/sys/class/block/sdd/device/rescan

but blkid still does not recognize the sdd disk.

blkid  | grep sdd

Why is that, and what we can do about this?

Answer 1

About blkid:

When device is specified [… (irrelevant)]. If none is given, all partitions or unpartitioned devices which appear in /proc/partitions are shown, if they are recognized.

While lsblk

lists information about all available or the specified block devices.

^{[Emphasis mine]}

Specify a device:

blkid /dev/sdd

Empty output indicates there in no structure from which blkid could read attributes (e.g. after wipefs -a /dev/sdd).