What is the Block Size Being Used by the Disk I/O Graph?
While there's currently not a way to view disk I/O in anything but blocks on this graph, I can tell you that the default size of these blocks is 512 bytes. This can be confirmed as accurate on your Linode by logging in and running
sudo fdisk -l /dev/sda. You should see something like the following:
$ sudo fdisk -l /dev/sda Disk /dev/sda: 10 GiB, 10737418240 bytes, 20971520 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes
While the size of your disk can vary, unless you've done something explicit to modify the block size, you should also find that your Linode is using 512 byte blocks.
Hope this helps!