X-Git-Url: http://git.tuebingen.mpg.de/?p=dss.git;a=blobdiff_plain;f=dss.ggo;h=51cfadd3391b41d4636c29b07411f93063a06413;hp=fe44aad9e78e94d1fce3bc63584910e5072d125b;hb=9c4bc98761828cbe3997e071ad5b4d24eb52e599;hpb=5690c1d32dd5de8419f2f0f37e4f075d7c2fb49d diff --git a/dss.ggo b/dss.ggo index fe44aad..51cfadd 100644 --- a/dss.ggo +++ b/dss.ggo @@ -1,150 +1,252 @@ +# +package "dss" +version "0.0.3" +purpose "the dyadic snapshot scheduler -text " -dss snapshot aging is implemented in terms of intervals. There are -two command line options related to intervals: the duration of a -'unit' interval and the number of those intervals. - -dss removes any snapshots older than the given number of intervals -times the duration of an unit interval and tries to keep the following -amount of snapshots per interval: - - interval number number of snapshots - =============================================== - 0 2 ^ (num_intervals - 1) - 1 2 ^ (num_intervals - 2) - 2 2 ^ (num_intervals - 3) - ... - num_intervals - 2 2 - num_intervals - 1 1 - num_intervals 0 - -In other words, the oldest snapshot will at most be unit_interval * -num_intervala old (= 5 days * 4 = 20 days if default values are used). -Moreover, there are at most 2^num_intervals - 1 snapshots in total -(i.e. 31 by default). Observe that you have to create at least -num_intervals snapshots each interval for this to work out. " - - +dss creates hardlink-based snapshots of a given directory on a remote +or local host using rsync's link-dest feature. +" -package "dss" -version "0.0.1" +######################### +section "General options" +######################### -option "config_file" c +option "config-file" c #~~~~~~~~~~~~~~~~~~~~~ "(default='~/.dssrc')" +string typestr="filename" +optional +details=" + Options may be given at the command line or in the + configuration file. As usual, if an option is given both at + the command line and in the configuration file, the command + line option takes precedence. + + However, there is an important exception to this rule: + If the --run option was given (see below) then dss honors + SIGHUP and re-reads its configuration file whenever it + receives this signal. In this case the options in the config + file override any options that were previously given at the + command line. This allows to change the configuration of a + running dss process on the fly by sending SIGHUP. + + Note that it is not possible to change whether dss runs as + background daemon by sending SIGHUP. +" + +option "daemon" d +#~~~~~~~~~~~~~~~~ +"Run as background daemon" +flag off +dependon="logfile" +details=" + Note that dss refuses to start in daemon mode if no logfile + was specified. This option is mostly useful in conjuction + with the -R option described below. +" - string typestr="filename" - optional +option "dry-run" D +#~~~~~~~~~~~~~~~~~ +"Only print what would be done" +flag off +details=" + This flag does not make sense for all commands. The run + command refuses to start if this option was given. The ls + command silently ignores this flag. +" +################# section "Logging" -#~~~~~~~~~~~~~~~~ +################# option "loglevel" l #~~~~~~~~~~~~~~~~~~ +"Set loglevel (0-6)" +int typestr="level" +default="3" +optional +details=" + Lower values mean less verbose logging. +" -"set loglevel (0-6)" +option "logfile" - +#~~~~~~~~~~~~~~~~~ +"Logfile for the dss daemon process" +string typestr="filename" +optional +details=" + This option is mostly useful for the run command if --daemon + is also given. +" - int typestr="level" - default="4" - optional +defgroup "command" +#================= +groupdesc=" + dss supports a couple of commands each of which corresponds to a different + command line option. Exactly one of these options must be given. +" +required -option "logfile" L -#~~~~~~~~~~~~~~~~~~ +groupoption "create" C +#~~~~~~~~~~~~~~~~~~~~~ +"Create a new snapshot" +group="command" +details=" + Execute the rsync command to create a new snapshot. Note that this + command does not care about free disk space. +" +groupoption "prune" P +#~~~~~~~~~~~~~~~~~~~~ +"Remove a redundant snapshot" +group="command" +details=" + A snapshot is considered redundant if it ether belongs to + an interval greater than the maximum number of intervals, + or if it belongs to an interval that already contains more + than the desired number of snapshots. +" -"logfile for the dss daemon process" +groupoption "ls" L +#~~~~~~~~~~~~~~~~~ +"Print a list of all snapshots" +group="command" +details=" + The list will contain all snapshots no matter of their state, + i. e. incomplete snapshots and snapshots being deleted will + also be listed. +" - string typestr="filename" - optional +groupoption "run" R +#~~~~~~~~~~~~~~~~~~ +"Start creating and pruning snapshots" +group="command" +details=" + This is the main mode of operation. Snapshots will be created + as needed and pruned automatically. +" -section "rsync-related options" -#============================== +############################### +section "Rsync-related options" +############################### -option "remote_user" U +option "remote-host" H #~~~~~~~~~~~~~~~~~~~~~ +"Remote host" +string typestr="hostname" +default="localhost" +optional +details=" + If this option is given and its value differs from the local + host, then rsync uses ssh. Make sure there is no password + needed for the ssh connection. To achieve that, use public key + authentication for ssh and, if needed, set the remote user name + by using the --remote-user option. +" -"remote user name (default: current user)" - - string typestr="username" - optional - -option "remote_host" H +option "remote-user" U #~~~~~~~~~~~~~~~~~~~~~ +"Remote user name (default: current user)" +string typestr="username" +optional +details=" + Set this if the user running dss is different from the + user at the remote host when using ssh. +" -"remote host" - - string typestr="hostname" - default="localhost" - optional - -option "source_dir" S +option "source-dir" - #~~~~~~~~~~~~~~~~~~~~ +"The data directory" +string typestr="dirname" +required +details=" + The directory on the remote host from which snapshots are + taken. Of course, the user specified as --remote-user must + have read access to this directory. +" -"directory to backup on the remote host" - - string typestr="dirname" - optional - -option "dest_dir" D +option "dest-dir" - #~~~~~~~~~~~~~~~~~~ +"Snapshot dir" +string typestr="dirname" +required +details=" + The destination directory on the local host where snapshots + will be written. This must be writable by the user who runs + dss. +" -"snapshots dir on the local host" - - string typestr="dirname" - optional - -option "rsync_option" O +option "rsync-option" O #~~~~~~~~~~~~~~~~~~~~~~ +"Further rsync options" +string typestr="option" +optional +multiple +details=" + These option may be given multiple times. The arguments passed + to that option are passed verbatim to the rsync command. +" -"further rsync options that are passed -verbatim to the rsync command." - - string typestr="option" - optional - multiple - - -option "exclude_patterns" e -#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -"rsync exclude patterns" - - string typestr="path" - optional - +option "exclude-patterns" e +#~~~~~~~~~~~~~~~~~~~~~~~~~~ +"Rsync exclude patterns" +string typestr="path" +optional +################### section "Intervals" -#~~~~~~~~~~~~~~~~~~ - +################### -option "unit_interval" u +option "unit-interval" u #~~~~~~~~~~~~~~~~~~~~~~~ -"the duration of a unit interval" - - int typestr="days" - default="4" - optional +"The duration of a unit interval" +int typestr="days" +default="4" +optional +details=" + dss snapshot aging is implemented in terms of intervals. There are + two command line options related to intervals: the duration of a + \"unit\" interval and the number of those unit intervals. + + dss removes any snapshots older than the given number of intervals + times the duration of a unit interval and tries to keep the following + number of snapshots per interval: + + interval number number of snapshots + =============================================== + 0 2 ^ (num-intervals - 1) + 1 2 ^ (num-intervals - 2) + 2 2 ^ (num-intervals - 3) + ... + num-intervals - 2 2 + num-intervals - 1 1 + num-intervals 0 + + In other words, the oldest snapshot will at most be unit_interval * + num_intervals old (= 5 days * 4 = 20 days if default values are used). + Moreover, there are at most 2^num_intervals - 1 snapshots in total + (i. e. 31 by default). Observe that you have to create at least + 2 ^ (num_intervals - 1) snapshots each interval for this to work out. +" -option "num_intervals" n +option "num-intervals" n #~~~~~~~~~~~~~~~~~~~~~~~ -"the number of unit intervals" - - int typestr="num" - default="5" - optional +"The number of unit intervals" +int typestr="num" +default="5" +optional +############### section "Hooks" -#============== +############### -option "pre_create_hook" r +option "pre-create-hook" r #~~~~~~~~~~~~~~~~~~~~~~~~~~ "Executed before snapshot creation" - - string typestr="command" - default="/bin/true" - optional - +string typestr="command" +default="/bin/true" +optional details=" - Execute this command before trying to create a new snapshot + Execute this command before trying to create a new snapshot. If this command returns with a non-zero exit status, do not perform the backup. One possible application of this is to return non-zero during office hours in order to not slow down @@ -152,14 +254,12 @@ details=" " -option "post_create_hook" o +option "post-create-hook" o #~~~~~~~~~~~~~~~~~~~~~~~~~~ "Executed after snapshot creation" - - string typestr="command" - default="/bin/true" - optional - +string typestr="command" +default="/bin/true" +optional details=" Execute this after a snapshot has successfully been created The return value on the command is ignored. For instance one @@ -167,56 +267,37 @@ details=" usage patterns in order to store them in a database for further treatment. " -option "creation_sleep" s -#~~~~~~~~~~~~~~~~~~~~~~~~ -"sleep interval" - int typestr="minutes" - default="60" - optional +############################### +section "Disk space monitoring" +############################### +option "min-free-mb" m +#~~~~~~~~~~~~~~~~~~~~~ +"Minimal amount of free disk space" +int typestr="megabytes" +default="100" +optional details=" - The sleep interval for snapshot creation in minutes. - The daemon will, in an endlees loop, create a snapshot and - then sleep that many minutes. -" + If less than this many megabytes of space is available on + the file system containing the destination directory, \"dss + --run\" will suspend the currently running rsync process and will + start to remove snapshots, starting from the oldest snapshot, + until the free disk space exceeds this value. See also the + --min_free_percent option. + A value of zero deactivates this check. -option "min_free" m -#~~~~~~~~~~~~~~~~~~ - -"minimal amount of free space" - - int typestr="gigabytes" - default="50" - optional - -details=" - If less that this many gigabytes of space is available, - dss will start to remove snapshots (starting from the oldest - snapshot) until the free disk space exeecds this value. " - -text " -subcommands: - -ls: - - Print list of existing snapshots. - - Usage: ls - -free: - - Remove old snapshots in order to free space. - - Usage: free [size] - - Without size parameter, print the amount of free space on the file system - in human-readable format. - - Otherwise, remove snapshots (starting from the oldest one) until the number of - free space exceeds the given number of gigabytes. - Use with caution! +option "min-free-percent" p +#~~~~~~~~~~~~~~~~~~~~~~~~~~ +"Minimal percent of free disk space" +int typestr="percent" +default="2" +optional +details=" + See --min-free-mb. Note that it is not recommended to set both + --min-free-mb and --min-free-percent to zero as this will + cause your file system to fill up quickly. "