Why it is not possible to set a disk size more than 16TB for OpenVZ container in SolusVM?
This limitation comes from OpenVZ and ploop file system layout itself:
CONFIG_TEXT: Currently ext4 file system is used. An ability to resize ext4 is limited by its block group descriptor table, which size can be specified during file system creation time, using
-Eresize option to mke2fs. Currently ploop library hardcodes this value so that filesystem can be resized up to 16 TB of space
Refer OpenVZ Wiki for more information about ploop limitations