I have an entity and I would like to describe it as being able to be archived.
Is it archivable, archiveable? The former seems OK for me, but I could find no wiktionary.org results.
It is archivable, in the same way from cite you get citable.
There are some differences between British English and American English. In British English, such adjectives (derived from a verb ending in -e) are preferred when they end with -eable; in American English, the preferred form ends in -able (the -e is removed from the verb).
The dictionary I have (the NOAD) doesn't report the word archivable, but it reports citable as derivative of cite, and archival as derivative of archive.