@sammarbella thanks for the reply. I thought I’d tried connecting via SMB before but I just tried it again and it did the trick: on a large directory (over 5000 files, each about 500k) AFP took about 5 minutes to enumerate the directory whereas SMB took 30 seconds. Thanks again for the suggestion.
It’s possible that AFP is faster than SMB in other scenarios I haven’t yet tested (streaming, file copying, etc) but we’ll see.
Also, for the benefit of anyone else encountering this issue, @DTrace’s suggestion also significantly improved my performance:
/etc/init.d/wdmcserverd stop
/etc/init.d/wdphotodbmergerd stop
# update-rc.d wdphotodbmergerd disable
# update-rc.d wdmcserverd disable
