splitting big authorized_keys files

[mike808]

What about this:

1. Break up your current file into mutliple files containing only keys
   based on the first two letters of the user name, as you suggested
   earlier.

2. Put them into a directory

3. Create symbolic (or hard) links for each username to their
   respective authorized_keys file.

4. Specifying the path to your authorized_keys "forest" in the server
   configuration value AuthorizedKeysFile and use the %u token as a suffix.

The server uses the authorized_keys file selected by the user name.
This file is actually a link to the (smaller) chunk of the old
authorized_keys file.

This effectively uses the filesystem as your "database", and the
only "index" available is the username, unfortunately.

Whether the filesystem finding the username "entry" in a directory
of 1500 "files", and then performing the key lookup (albeit in a
smaller file), is faster than SSH looking up the key in the larger
authorized_keys file, only you can decide.

It's not a "great" way to do this, but it could work. The authorized_keys
files get more manageable, but then the directory you put them in
gets more unmanagable with all of the user links in it.

HTH,
Mike/