markdown: add it and write some

.gitignore

@@ -3,6 +3,7 @@
 *.new
 *.so*
 Doxyfile
+README.html
 depends.mk
 doxygen_*
 html/

Makefile

@@ -1,4 +1,4 @@
-default install all: lib src test
+default install all: lib src test README.html
 
 clean:
 	git clean -dfx
@@ -13,3 +13,7 @@ src: lib
 
 test: lib src
 	$(MAKE) -C test
+
+README.html: README.md
+	markdown README.md > README.html.new
+	mv -f README.html.new README.html

README.md

@@ -0,0 +1,88 @@
+BEES
+====
+
+Best-Effort Extent-Same, a btrfs deduplicator.
+
+TODO
+----
+
+Write some docs here:
+
+* copyright (Zygo Blaxell 2015-2016), license (GPL3+)
+* what it is
+* what it isn't
+* building it
+* what works
+* what doesn't work
+* a brief history of btrfs kernel bugs
+* things that could have been, and why they aren't
+* roadmap (and anti-roadmap)
+* how to report bugs
+* how to contribute
+
+Build
+-----
+
+Requirements:
+	* C++11 compiler (I use GCC 4.9)
+	* btrfs-progs (I've used 4.1..4.7) for /usr/include/btrfs/*
+	* libuuid-dev (TODO: remove the one function we call from this library)
+
+Build with `make`.
+
+The build produces `bin/bees` and `lib/libcrucible.so`, which must be
+copied to somewhere in `$PATH` and `$LD_LIBRARY_PATH` on the target
+system respectively.
+
+Setup
+-----
+
+Create a directory for bees state files:
+
+	export BEESHOME=/some/path
+	mkdir -p "$BEESHOME"
+
+Create an empty hash table (your choice of size, but it must be a multiple
+of 16M).  This example creates a 1GB hash table:
+
+	truncate -s 1g "$BEESHOME/beeshash.dat"
+	chmod 700 "$BEESHOME/beeshash.dat"
+
+Configuration
+-------------
+
+The only runtime configurable options are environment variables:
+
+* BEESHOME: Directory containing Bees state files:
+ * beeshash.dat         | persistent hash table (must be a multiple of 16M)
+ * beescrawl.`UUID`.dat | state of SEARCH_V2 crawlers
+ * beesstats.txt        | statistics and performance counters
+* BEESSTATS: File containing a snapshot of current Bees state (performance
+  counters and current status of each thread).
+
+Other options (e.g. interval between filesystem crawls) can be configured
+in src/bees.h.
+
+Running
+-------
+
+We created this directory in the previous section.
+
+	export BEESHOME=/some/path
+
+Use a tmpfs for BEESSTATUS, it updates once per second
+
+	export BEESSTATUS=/run/bees.status
+
+bees can only process the root subvol of a btrfs.
+Use a bind mount, and let only bees access it.
+
+	mount -osubvol=/ /dev/<your-filesystem> /var/lib/bees/root
+
+Let the bees fly!
+
+	bees /var/lib/bees/root >> /var/log/bees.log 2>&1
+
+You'll probably want to arrange for /var/log/bees.log to be rotated
+periodically.  You may also want to set umask to 077 to prevent disclosure
+of information about the contents of the filesystem through the log file.