1DRBDLINKS(8) System Manager's Manual DRBDLINKS(8)
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6 drbdlinks - manages links into a shared DRBD partition
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9 drbdlinks [OPTION]... [start|stop|auto|status|monitor|checklinks]
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12 drbdlinks is a program that will manage creation and removal of sym‐
13 bolic links. It is primarily used with clusters of machines using
14 either shared storage or the "DRBD" replicated block device.
15 While the name of the program is "drbdlinks", it can be used in any
17 shared-storage sort of environment where the shared storage is only
18 mounted on the active node. In cases like NFS where the shared storage
19 is always mounted on all nodes, drbdlinks is not necessary.
20 The advantage over creating static symbolic links is that package
22 updates often require that directories point at real files, so updates
23 can often fail if you do not have the shared storage mounted.
24 drbdlinks also supports multiple instances of links, in the case of
26 active/active clusters. For example, if you have MySQL running in one
27 resource group, and Apache running in another, you can use the "-c"
28 switch to specify a configuration file for each resource group.
29 A simple configuration file, "/etc/drbdlinks.conf", specifies the
31 links. This can be used to manage links for /etc/httpd,
32 /var/lib/pgsql, and other system directories that need to appear as if
33 they are local to the system when running applications after a drbd
34 shared partition has been mounted.
35 Optionally, configuration directives can also be written to files in
37 "/etc/drbdlinks.d" with the suffix ".conf", which are loaded after the
38 "/etc/drbdlinks.conf" file, in sorted order.
39 When run with "start" as the mode, drbdlinks will rename the existing
41 files/directories, and then make symbolic links into the DRBD parti‐
42 tion. "stop" does the reverse.
43 Mode "checklinks" will report any links that do not exist in the desti‐
45 nation area. During initial setup and configuration, this can help
46 check that you have the destination file-system set up with the
47 required components.
48 If run with "initialize_shared_storage", destination links specified in
50 the configuration file will be populated from the source storage. This
51 is useful for initial setup to populate the shared storage. Preceding
52 paths will be populated if they share the same name from source to des‐
53 tination.
54 The "monitor" and "status" modes will check the file-system against the
56 configuration file and will report "running" (monitor mode) or "OK"
57 (status mode) if all links appear to be up. Otherwise they report
58 "down" or "stopped" (respectively).
59 By default, the rename appends .drbdlinks to the name, but this can be
61 overridden in the configuration file.
62 The "list" mode just show the list of links, with each line showing the
64 link, destination, and a 0/1 flag for bindMount status. This may be
65 useful for user scripts without having to parse the configuration.
66 An init script is included which runs "stop" before heartbeat starts,
68 and after heartbeat stops. This is done to try to ensure that when the
69 shared partition isn't mounted, the links are in their normal state.
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73 drbdlinks has several options, using either short or long variants.
74 -h, --help
76 Print a short help message describing the available options and
77 exit.
78 -c, --config-file=CONFIGFILE
81 Specify an alternate config file. The default config file is
82 /etc/drbdlinks.conf. Alternate config files should have a "drb‐
83 dlinks-" prefix, e.g. "drbdlinks-httpd.conf".
84 -s, --suffix=SUFFIX
87 Name to append to the local file-system name when the link is in
88 place. The default is "drbdlinks", which would result in a
89 renamed file like "/etc/httpd.drbdlinks".
90 -v, --verbose
93 Increase verbosity level by 1 for every occurrence of this
94 option.
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98 Here are a few examples of how drbdlinks can be used.
99 The most straight-forward, and default, method for starting drbdlinks:
101 drbdlinks start
103 To use a suffix different from the default when linking to a file or
105 directory, the -s option can be used, specifying the desired string:
106 drbdlinks -s orig start
108 would rename the file-system name to "name.orig".
110 Increase the verbosity to assist in debugging:
112 drbdlinks -v -v start
114 Use an alternate configuration file, possibly from with a DRBD mounted
116 file-system:
117 drbdlinks -c /shared1/drbdlinks-httpd.conf start
119 This would use the specified configuration file, found on our DRBD
121 device mounted on /shared1. This would allow us to easily keep drb‐
122 dlinks configurations tied to a specific set of data on a DRBD disk in
123 an active/active sort of HA configuration.
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128 DRBD(8), drbdadm(8), drbdsetup(8), heartbeat(8).
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131 drbdlinks was written by Sean Reifschneider <jafo@tummy.com>.
132 This manual page was written by Cyril Bouthors <cyril@bouthors.org>,
134 for the Debian project (but may be used by others). Sean Reifschneider
135 modified it for status and monitor arguments, and included it in the
136 base drbdlinks release. Mike Loseke <mike@tummy.com> added the sec‐
137 tions on options and examples.
138 September 3, 2008 DRBDLINKS(8)