-[[meta title="inside .ikiwiki"]]
+[[!meta title="inside .ikiwiki"]]
The `.ikiwiki` directory contains ikiwiki's internal state. Normally,
you don't need to look in it, but here's some tips for how to do so if
## the index
-`.ikiwiki/indexdb` contains a cache of information about pages, as well
-as all persisitant state about pages. It used to be a (semi) human-readable
-text file, but is not anymore.
+`.ikiwiki/indexdb` contains a cache of information about pages.
+This information can always be recalculated by rebuilding the wiki.
+(So the file is safe to delete and need not be backed up.)
+It used to be a (semi) human-readable text file, but is not anymore.
To dump the contents of the file, enter a perl command like this.
I've not written actual utilities to do this yet because I've only needed
to do it rarely, and the data I've wanted has been different each time.
--[[Joey]]
+
+## the session database
+
+`.ikiwiki/sessions.db` is the session database. See the [[!cpan CGI::Session]]
+documentation for more details.
+
+## lockfiles
+
+In case you're curious, here's what the various lock files do.
+
+* `.ikiwiki/lockfile` is the master ikiwiki lock file. Ikiwiki takes this
+ lock before reading/writing state.
+* `.ikiwiki/commitlock` is locked as a semophore, to disable the commit hook
+ from doing anything.
+* `.ikiwiki/cgilock` is locked by the cgi wrapper, to ensure that only
+ one ikiwiki process is run at a time to handle cgi requests.
+
+## plugin state files
+
+Some plugins create other files to store their state.
+
+* `.ikiwiki/aggregate` is a plain text database used by the aggregate plugin
+ to record feeds and known posts.
+* `.ikiwiki/xapian/` is created by the search plugin, and contains xapian-omega
+ configuration and the xapian database.