• Mac OS X,  Mac OS X Server,  Mac Security,  Mass Deployment

    Open Directory Backups Fail Due To HostName Problems

    If you don’t have a HostName set on your computer then Open Directory backups are likely to fail using Time Machine. How did you promote to an Open Directory Master if you don’t have functional backups you may ask? Let’s not worry about that for now. Instead, let’s turn our attention to /var/backups. You see, if you enable Time Machine on an OS X Server, you’ll get a ServerBackup_OpenDirectoryMaster.sparseimage in that folder, which contains your Open Directory backups and gets picked up by our pal Time Machine. You can manually run a backup using the opendirectorybackup script at /Applications/Server.app/Contents/ServerRoot/usr/libexec/server_backup/opendirectorybackup. This could be automated, using expect to send a password, but…

  • Mac OS X,  Mac OS X Server,  Mac Security,  Mass Deployment

    Setting Up & Troubleshooting An Open Directory Replica In OS X Mountain Lion Server

    Yesterday we looked at setting up an Open Directory Master in OS X Mountain Lion Server. An Open Directory Replica keeps a copy of the Open Directory database available for users even when the Master goes offline. But it can also take a part of the load from the Open Directory Master and when using the new Locales feature, balance network traffic. To get started with an Open Directory Replica, first enable SSH, now disabled by default. Next, use the changeip to check the host name. While the Server app is cool, it caches stuff and I’ve seen it let things go threat shouldn’t be let go. Therefore, in order…

  • Mac OS X Server,  Unix

    Replica Trees & Tuning Open Directory

    You have a fairly large Open Directory environment and you go to add the 33rd replica but you get a funny error that dserr doesn’t have listed. The reason is likely that a single Open Directory Master can only have 32 replicas. However, you can have 32 replicas on each replica (thus having a replica tree), ergo allowing for a total of 1,024 replicas and a master. So rather than bind that 33rd replica to a master, move to a replica tree model, trying to offload replicas in as geographically friendly a fashion as possible (thus reducing slap traffic on your WAN links) by repositioning replicas per site. Similar to…