It very much depends on the work(s) on the disk and its purpose.
For one or two long works by a single composer -- for instance, two
symphonies by Brahms, or three Brandenburg Concertos by Bach, then the
composer comes first.
Occasionally, record companies put out extended series of "all" of
some respected performer's recordings -- for instance RCA did it for
Caruso and for Arthur Rubenstein. Then it's up to the collector
whether it's important to keep the set together -- do you intend to
get all the items? -- or to keep, say, all your Beethoven piano
sonatas together.
For solo recitals (singer or instrumentalist with accompanist), often
several composers are represented, so naturally it goes under the
performer's name. Rarely would the accompanist be the featured player,
though there are very rare exceptions.
For chamber music, usually it's an established ensemble with a name --
the Juilliard Quartet, the Beaux Arts Trio -- but their albums usually
featuer a single composer's works, so again it's a matter of where you
want to put the emphasis.
Me, I keep all my one-composer disks in a single alphabetical order
(mixing together "classical" and "opera"), and they're followed by the
"recital" disks -- vocal solos, then duets etc., then choruses; then
instrumental albums, starting with solo (piano, organ, etc.), then
going up by size of ensemble, till we end up with miscellaneous disks
of orchestral music. (I don't have many of those because they don't
often feature complete works.)