Berkeley DB allows you to specify programmatically and via DB_CONFIG alternative
directories for database and logfiles used in a given environment (the
"set_lg_dir" and "set_data_dir" directives). If you make use of such things in
your Subversion repositories, most things work just fine. But any APIs which
presume that logfiles or database files live in the environment directory are
broken. One obvious example (svn_fs_berkeley_logfiles) comes to mind -- using
'svnadmin list-dblogs' or 'svnadmin list-unused-dblogs' on a so-configured
repository will return bogus paths. There might also be problems with the
hotcopy code, but I've not verified that.