-
bup: It backs things up
=======================
for you, but we don't know why. It is also missing some
probably-critical features.
- - It requires python >= 2.4, a C compiler, and an installed git version >=
- 1.5.3.1.
+ - It requires python >= 2.6, a C compiler, and an installed git
+ version >= 1.5.3.1. It also requires par2 if you want fsck to be
+ able to generate the information needed to recover from some types
+ of corruption.
- - It currently only works on Linux, MacOS X >= 10.4, or Windows (with
- Cygwin). Patches to support other platforms are welcome.
-
-
+ - It currently only works on Linux, FreeBSD, NetBSD, OS X >= 10.4,
+ Solaris, or Windows (with Cygwin). Patches to support other
+ platforms are welcome.
+
+ - Any items in "Things that are stupid" below.
+
+
+Notable changes introduced by a release
+=======================================
+
+ - <a href="note/0.29.1-from-0.29.md">Changes in 0.29.1 as compared to 0.29</a>
+ - <a href="note/0.29-from-0.28.1.md">Changes in 0.29 as compared to 0.28.1</a>
+ - <a href="note/0.28.1-from-0.28.md">Changes in 0.28.1 as compared to 0.28</a>
+ - <a href="note/0.28-from-0.27.1.md">Changes in 0.28 as compared to 0.27.1</a>
+ - <a href="note/0.27.1-from-0.27.md">Changes in 0.27.1 as compared to 0.27</a>
+
+
Getting started
----------------
+===============
+
+From source
+-----------
- Check out the bup source code using git:
- git clone git://github.com/apenwarr/bup
-
- - Install the needed python libraries (including the development
- libraries). On Debian or Ubuntu, this is usually:
- apt-get install python2.6-dev python-fuse
-
- Substitute python2.5-dev or python2.4-dev if you have an older system.
-
+ git clone https://github.com/bup/bup
+
+ - Install the required python libraries (including the development
+ libraries).
+
+ On very recent Debian/Ubuntu versions, this may be sufficient (run
+ as root):
+
+ apt-get build-dep bup
+
+ Otherwise try this (substitute python2.6-dev if you have an older
+ system):
+
+ apt-get install python2.7-dev python-fuse
+ apt-get install python-pyxattr python-pylibacl
+ apt-get install linux-libc-dev
+ apt-get install acl attr
+ apt-get install python-tornado # optional
+
+ On CentOS (for CentOS 6, at least), this should be sufficient (run
+ as root):
+
+ yum groupinstall "Development Tools"
+ yum install python python-devel
+ yum install fuse-python pyxattr pylibacl
+ yum install perl-Time-HiRes
+
+ In addition to the default CentOS repositories, you may need to add
+ RPMForge (for fuse-python) and EPEL (for pyxattr and pylibacl).
+
+ On Cygwin, install python, make, rsync, and gcc4.
+
+ If you would like to use the optional bup web server on systems
+ without a tornado package, you may want to try this:
+
+ pip install tornado
+
- Build the python module and symlinks:
-
+
make
- Run the tests:
make test
- (The tests should pass. If they don't pass for you, stop here and send
- me an email.)
-
- - Try making a local backup as a tar file:
+ The tests should pass. If they don't pass for you, stop here and
+ send an email to bup-list@googlegroups.com. Though if there are
+ symbolic links along the current working directory path, the tests
+ may fail. Running something like this before "make test" should
+ sidestep the problem:
+
+ cd "$(pwd -P)"
+
+ - You can install bup via "make install", and override the default
+ destination with DESTDIR and PREFIX.
+
+ Files are normally installed to "$DESTDIR/$PREFIX" where DESTDIR is
+ empty by default, and PREFIX is set to /usr/local. So if you wanted to
+ install bup to /opt/bup, you might do something like this:
+
+ make install DESTDIR=/opt/bup PREFIX=''
+
+ - The Python executable that bup will use is chosen by ./configure,
+ which will search for a reasonable version unless PYTHON is set in
+ the environment, in which case, bup will use that path. You can
+ see which Python executable was chosen by looking at the
+ configure output, or examining cmd/python-cmd.sh, and you can
+ change the selection by re-running ./configure.
+
+From binary packages
+--------------------
+
+Binary packages of bup are known to be built for the following OSes:
+
+ - Debian:
+ http://packages.debian.org/search?searchon=names&keywords=bup
+ - Ubuntu:
+ http://packages.ubuntu.com/search?searchon=names&keywords=bup
+ - pkgsrc (NetBSD, Dragonfly, and others)
+ http://pkgsrc.se/sysutils/bup
+ http://cvsweb.netbsd.org/bsdweb.cgi/pkgsrc/sysutils/bup/
+ - Arch Linux:
+ https://www.archlinux.org/packages/?sort=&q=bup
+ - Fedora:
+ https://apps.fedoraproject.org/packages/bup
+
+
+Using bup
+---------
+
+ - Get help for any bup command:
+
+ bup help
+ bup help init
+ bup help index
+ bup help save
+ bup help restore
+ ...
+
+ - Initialize the default BUP_DIR (~/.bup):
+
+ bup init
+
+ - Make a local backup (-v or -vv will increase the verbosity):
+
+ bup index /etc
+ bup save -n local-etc /etc
+
+ - Restore a local backup to ./dest:
+
+ bup restore -C ./dest local-etc/latest/etc
+ ls -l dest/etc
+
+ - Look at how much disk space your backup took:
+
+ du -s ~/.bup
+
+ - Make another backup (which should be mostly identical to the last one;
+ notice that you don't have to *specify* that this backup is incremental,
+ it just saves space automatically):
+
+ bup index /etc
+ bup save -n local-etc /etc
+
+ - Look how little extra space your second backup used (on top of the first):
+
+ du -s ~/.bup
+
+ - Get a list of your previous backups:
+
+ bup ls local-etc
+
+ - Restore your first backup again:
+
+ bup restore -C ./dest-2 local-etc/2013-11-23-11195/etc
+
+ - Make a backup to a remote server which must already have the 'bup' command
+ somewhere in its PATH (see /etc/profile, etc/environment, ~/.profile, or
+ ~/.bashrc), and be accessible via ssh.
+ Make sure to replace SERVERNAME with the actual hostname of your server:
+
+ bup init -r SERVERNAME:path/to/remote-bup-dir
+ bup index /etc
+ bup save -r SERVERNAME:path/to/remote-bup-dir -n local-etc /etc
+
+ - Make a remote backup to ~/.bup on SERVER:
+
+ bup index /etc
+ bup save -r SERVER: -n local-etc /etc
+
+ - See what saves are available in ~/.bup on SERVER:
+
+ bup ls -r SERVER:
+
+ - Restore the remote backup to ./dest:
+
+ bup restore -r SERVER: -C ./dest local-etc/latest/etc
+ ls -l dest/etc
+
+ - Defend your backups from death rays (OK fine, more likely from the
+ occasional bad disk block). This writes parity information
+ (currently via par2) for all of the existing data so that bup may
+ be able to recover from some amount of repository corruption:
+
+ bup fsck -g
+
+ - Use split/join instead of index/save/restore. Try making a local
+ backup using tar:
tar -cvf - /etc | bup split -n local-etc -vv
- - Try restoring your backup tarball:
+ - Try restoring the tarball:
bup join local-etc | tar -tf -
du -s ~/.bup
- - Make another backup (which should be mostly identical to the last one;
- notice that you don't have to *specify* that this backup is incremental,
- it just saves space automatically):
+ - Make another tar backup:
tar -cvf - /etc | bup split -n local-etc -vv
- - Look how little extra space your second backup used on top of the first:
+ - Look at how little extra space your second backup used on top of
+ the first:
du -s ~/.bup
- - Restore your old backup again (the ~1 is git notation for "one older than
- the most recent"):
+ - Restore the first tar backup again (the ~1 is git notation for "one
+ older than the most recent"):
bup join local-etc~1 | tar -tf -
- - Get a list of your previous backups:
+ - Get a list of your previous split-based backups:
GIT_DIR=~/.bup git log local-etc
- - Make a backup on a remote server (which must already have the 'bup' command
- somewhere in the server's PATH (see /etc/profile, etc/environment,
- ~/.profile, or ~/.bashrc), and be accessible via ssh.
- Make sure to replace SERVERNAME with the actual hostname of your server):
+ - Save a tar archive to a remote server (without tar -z to facilitate
+ deduplication):
tar -cvf - /etc | bup split -r SERVERNAME: -n local-etc -vv
- - Try restoring the remote backup tarball:
+ - Restore the archive:
bup join -r SERVERNAME: local-etc | tar -tf -
- - Try using the new (slightly experimental) 'bup index' and 'bup save'
- style backups, which bypass 'tar' but have some missing features (see
- "Things that are stupid" below):
-
- bup index -uv /etc
- bup save -n local-etc /etc
-
- - Do it again and see how fast an incremental backup can be:
-
- bup index -uv /etc
- bup save -n local-etc /etc
-
- (You can also use the "-r SERVERNAME:" option to 'bup save', just like
- with 'bup split' and 'bup join'. The index itself is always local,
- so you don't need -r there.)
-
That's all there is to it!
+Notes on FreeBSD
+----------------
+
+- FreeBSD's default 'make' command doesn't like bup's Makefile. In order to
+ compile the code, run tests and install bup, you need to install GNU Make
+ from the port named 'gmake' and use its executable instead in the commands
+ seen above. (i.e. 'gmake test' runs bup's test suite)
+
+- Python's development headers are automatically installed with the 'python'
+ port so there's no need to install them separately.
+
+- To use the 'bup fuse' command, you need to install the fuse kernel module
+ from the 'fusefs-kmod' port in the 'sysutils' section and the libraries from
+ the port named 'py-fusefs' in the 'devel' section.
+
+- The 'par2' command can be found in the port named 'par2cmdline'.
+
+- In order to compile the documentation, you need pandoc which can be found in
+ the port named 'hs-pandoc' in the 'textproc' section.
+
+
+Notes on NetBSD/pkgsrc
+----------------------
+
+ - See pkgsrc/sysutils/bup, which should be the most recent stable
+ release and includes man pages. It also has a reasonable set of
+ dependencies (git, par2, py-fuse-bindings).
+
+ - The "fuse-python" package referred to is hard to locate, and is a
+ separate tarball for the python language binding distributed by the
+ fuse project on sourceforge. It is available as
+ pkgsrc/filesystems/py-fuse-bindings and on NetBSD 5, "bup fuse"
+ works with it.
+
+ - "bup fuse" presents every directory/file as inode 0. The directory
+ traversal code ("fts") in NetBSD's libc will interpret this as a
+ cycle and error out, so "ls -R" and "find" will not work.
+
+ - There is no support for ACLs. If/when some entrprising person
+ fixes this, adjust t/compare-trees.
+
+
+Notes on Cygwin
+---------------
+
+ - There is no support for ACLs. If/when some enterprising person
+ fixes this, adjust t/compare-trees.
+
+ - In t/test.sh, two tests have been disabled. These tests check to
+ see that repeated saves produce identical trees and that an
+ intervening index doesn't change the SHA1. Apparently Cygwin has
+ some unusual behaviors with respect to access times (that probably
+ warrant further investigation). Possibly related:
+ http://cygwin.com/ml/cygwin/2007-06/msg00436.html
+
+
+Notes on OS X
+-------------
+
+ - There is no support for ACLs. If/when some enterprising person
+ fixes this, adjust t/compare-trees.
+
+
How it works
-------------
+============
Basic storage:
+--------------
bup stores its data in a git-formatted repository. Unfortunately, git
itself doesn't actually behave very well for bup's use case (huge numbers of
Basically, 'bup split' reads the data on stdin (or from files specified on
the command line), breaks it into chunks using a rolling checksum (similar to
-rsync), and saves those chunks into a new git packfile. There is one git
-packfile per backup.
+rsync), and saves those chunks into a new git packfile. There is at least one
+git packfile per backup.
When deciding whether to write a particular chunk into the new packfile, bup
first checks all the other packfiles that exist to see if they already have that
scripts that do something with those values.
The bup index:
+--------------
'bup index' walks through your filesystem and updates a file (whose name is,
by default, ~/.bup/bupindex) to contain the name, attributes, and an
Things that are stupid for now but which we'll fix later
---------------------------------------------------------
+========================================================
Help with any of these problems, or others, is very welcome. Join the
mailing list (see below) if you'd like to help.
- - 'bup save' and 'bup restore' don't know about file metadata.
+ - 'bup save' and 'bup restore' have immature metadata support.
- That means we aren't saving file attributes, mtimes, ownership, hard
- links, MacOS resource forks, etc. Clearly this needs to be improved.
+ On the plus side, they actually do have support now, but it's new,
+ and not remotely as well tested as tar/rsync/whatever's. However,
+ you have to start somewhere, and as of 0.25, we think it's ready
+ for more general use. Please let us know if you have any trouble.
+
+ Also, if any strip or graft-style options are specified to 'bup
+ save', then no metadata will be written for the root directory.
+ That's obviously less than ideal.
+
+ - bup is overly optimistic about mmap. Right now bup just assumes
+ that it can mmap as large a block as it likes, and that mmap will
+ never fail. Yeah, right... If nothing else, this has failed on
+ 32-bit architectures (and 31-bit is even worse -- looking at you,
+ s390).
+
+ To fix this, we might just implement a FakeMmap[1] class that uses
+ normal file IO and handles all of the mmap methods[2] that bup
+ actually calls. Then we'd swap in one of those whenever mmap
+ fails.
+
+ This would also require implementing some of the methods needed to
+ support "[]" array access, probably at a minimum __getitem__,
+ __setitem__, and __setslice__ [3].
+
+ [1] http://comments.gmane.org/gmane.comp.sysutils.backup.bup/613
+ [2] http://docs.python.org/2/library/mmap.html
+ [3] http://docs.python.org/2/reference/datamodel.html#emulating-container-types
- 'bup index' is slower than it should be.
give the continuous-backup process a really low CPU and I/O priority so
you wouldn't even know it was running.
- - bup currently has no features that prune away *old* backups.
-
- Because of the way the packfile system works, backups become "entangled"
- in weird ways and it's not actually possible to delete one pack
- (corresponding approximately to one backup) without risking screwing up
- other backups.
-
- git itself has lots of ways of optimizing this sort of thing, but its
- methods aren't really applicable here; bup packfiles are just too huge.
- We'll have to do it in a totally different way. There are lots of
- options. For now: make sure you've got lots of disk space :)
+ - bup only has experimental support for pruning old backups.
+
+ While you should now be able to drop old saves and branches with
+ `bup rm`, and reclaim the space occupied by data that's no longer
+ needed by other backups with `bup gc`, these commands are
+ experimental, and should be handled with great care. See the
+ man pages for more information.
- - bup has never been tested on anything but Linux, MacOS, and Windows+Cygwin.
+ Unless you want to help test the new commands, one possible
+ workaround is to just start a new BUP_DIR occasionally,
+ i.e. bup-2013, bup-2014...
+
+ - bup has never been tested on anything but Linux, FreeBSD, NetBSD,
+ OS X, and Windows+Cygwin.
There's nothing that makes it *inherently* non-portable, though, so
that's mostly a matter of someone putting in some effort. (For a
- bup needs better documentation.
- According to a recent article about git in Linux Weekly News
+ According to a recent article about bup in Linux Weekly News
(https://lwn.net/Articles/380983/), "it's a bit short on examples and
a user guide would be nice." Documentation is the sort of thing that
will never be great unless someone from outside contributes it (since
- bup has no GUI.
- Actually, that's not stupid, but you might consider it a limitation.
- There are a bunch of Linux GUI backup programs; someday I expect someone
- will adapt one of them to use bup.
+ Actually, that's not stupid, but you might consider it a
+ limitation. See the ["Related Projects"](https://bup.github.io/)
+ list for some possible options.
+
+More Documentation
+==================
+
+bup has an extensive set of man pages. Try using 'bup help' to get
+started, or use 'bup help SUBCOMMAND' for any bup subcommand (like split,
+join, index, save, etc.) to get details on that command.
+
+For further technical details, please see ./DESIGN.
How you can help
-----------------
+================
bup is a work in progress and there are many ways it can still be improved.
If you'd like to contribute patches, ideas, or bug reports, please join the
bup-list+subscribe@googlegroups.com
+Please see <a href="HACKING">./HACKING</a> for
+additional information, i.e. how to submit patches (hint - no pull
+requests), how we handle branches, etc.
+
+
Have fun,
Avery
projects / bup.git / blobdiff