feat(instances): explain how to identify SBS volumes

compute/instances/reference-content/identify-devices.mdx

@@ -96,6 +96,26 @@ Note that this rule relies on `ID_VENDOR` and `ID_SERIAL_SHORT` being in the env
 
 For more details on writing `udev` rules, please see `man 7 udev`.
 
+# Identifying Block Storage volumes (SBS)
+
+Block Storage devices are similar to Instance block storage devices. They are also connected to the Instance as SCSI devices and thus all explanations from the above section are also valid.
+
+The only difference is the SCSI model attribute. Instead of being fixed to the value `b_ssd`, its value depends on the class of the Block Storage volume.
+
+Two Block Storage volumes classes currently exist: `bssd`, and `sbs`. Block Storage volumes migrated from Instance block storage (`b_ssd`) volumes have class `bssd`.
+
+Block Storage volumes with class `bssd` have a SCSI model of `b_ssd`, so migrated volumes won't change characteristics. Otherwise, Block Storage volumes have a SCSI model equal to the volume's class. 
+
+For example:
+
+```sh
+root@test-instance:~# lsblk --scsi
+NAME HCTL       TYPE VENDOR   MODEL  REV SERIAL                                      TRAN
+sda  0:0:0:0    disk SCW      sbs    v42 volume-7831d52c-758f-4a94-a074-39bfa14b66d8
+sdb  0:0:1:0    disk SCW      b_ssd  v42 volume-03e206f6-2a3b-4223-bb56-3d7f1495903f
+```
+
+Here, the first volume has been created through the Block Storage API with class `sbs`. The second volume is an Instance block storage (`b_ssd`) volume which has been migrated to Block Storage, and is now a Block Storage volume with class `bssd`.
 
 # Identifying VPC Private Network interfaces