Powers of 10 vs Powers of 2
The computer industry has for decades made a mess of these sizes, sometimes meaning base 10 and sometimes meaning base 2. This is done inconsistently between contexts and between various sectors of the industry such as computer memory, data transmission, and hard disk storage.
Kilo/Kibi, Mega/Mebi, Giga/Gibi
As of 1998 names were officially standardized. The familiar metric prefixes (kilo, mega, giga, etc.) are used for decimal (powers of 10) numbers. New prefixes with
bi for ‘binary’ (kibi , mebi, gibi, etc.) were invented for binary numbers (powers of 2).
See a good discussion on the Wikipedia page for Gibibyte and the page for binary prefix.
As for database administration, there is no specific issue except that such work typically treads across those sectors of memory, networking, and storage. So you will encounter all the various definitions and their abuses.
The upshot: Read the fine print to determine the exact definition in play in any specific situation. The storage industry in particular has gotten much better in recent years about defining their terms quite clearly in the fine print of ads, brochures, and documentation.