Tuesday, 29 July 2014

Backing up and Nuke OSX 10.8 Calendar Server


There's various bits of documentation around about how to do this on 10.7 Server, but although the principal is correct it doesn't work on 10.8

The reason for this is that in 10.8 there are two instances of the postgres daemon.

One is in user land, for sysadmins to setup their own databases, and is also used by Roundcube Topic Desk. The second is hidden and is used to store the servers data such as calendar events and wikis.

The 10.7 instructions to backup the DB are:
sudo pg_dump -U _postgres caldav -c -f caldav.sql

If you run this on 10.8 server it will fail, saying that it can't find the caldav database.

The only way to access the caldav db is via a unix domain socket located at:
/Library/Server/PostgreSQL\ For\ Server\ Services/Socket/.s.PGSQL.5432

You can verify this by using telnet to connect to it:
telnet -u /Library/Server/PostgreSQL\ For\ Server\ Services/Socket/.s.PGSQL.5432

** Note, a service that uses the postgres db must be running for the socket to exist.

In addition, the pg_dump program located on the standard path, i.e. /usr/bin is the wrong version to access the postgres damon hosting the service databases, there is another version hidden away within the server app at:

Even if you call this directly, it will fail because it tries to access the standard TCP port for postgres.

So, we need to use the pg_dump in the server app, and pass the socket location to it.

Luckily we can do this with the host flag, from the man page:
-h host, --host=host
           Specifies the host name of the machine on which the server is running. If the value begins with a slash, it is used as the directory for the Unix domain socket.
           The default is taken from the PGHOST environment variable, if set, else a Unix domain socket connection is attempted.

It appends the socket file name, so actually only wants the path.

Putting this all together, we can successfully backup the caldav DB with the following command:
/Applications/Server.app/Contents/ServerRoot/usr/bin/pg_dump -U _postgres -h /Library/Server/PostgreSQL\ For\ Server\ Services/Socket/ caldav -c -f caldav.sql

This will backup the DB that contains all the events, however there is also another program hidden in the server app that we need to run that will backup the sqlite dbs and the server settings.


To backup, pass the following:
/Applications/Server.app/Contents/ServerRoot/usr/sbin/calendarserver_backup backup file.tgz

To restore
/Applications/Server.app/Contents/ServerRoot/usr/sbin/calendarserver_backup restore file.tgz

If you run it without any options or with -h it will give you basic help info.

Nuke and Rebuild

So now we know how to backup the DB, what if we want to wipe it and start again?
To do this we need to drop the caldav db, and then run calendarserver_bootstrap_database to recreate the DB.

However, the socket only exists when services that use the db are running, and you can't drop the db if it's being used.

To overcome this, luckily the wiki service uses the postgres daemon and creates the socket, but does not lock the caldav db.

Step 1…. get the background postgres daemon working..

In Server App
Stop Calendar
Stop Contacts 
Start Wiki

Step 2.. drop the caldav DB

sudo /Applications/Server.app/Contents/ServerRoot/usr/bin/dropdb -U _postgres -h /Library/Server/PostgreSQL\ For\ Server\ Services/Socket/ caldav

Step 3 … rebuild the caldav DB

sudo calendarserver_bootstrap_database -v

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