TypePad is considered the largest paid blogging service in the world. After experience problems because of their meteoric growth, they eventually transitioned to an architecture patterned after their sister company, LiveJournal.
- Single server running Linux, Apache, Postgres, Perl, mod_perl
- Storage was NFS on a filer.
- A RAID controller failed and spewed data across all RAID disks.
- The database was corrupted and the backups were corrupted.
- Their redundant filers suffered from "split brain" syndrome.
- Replicated MySQL clusters partitioned by ID.
- A global DB generated globally unique sequence numbers and mapped users to partitions.
- Other data was mapped by role.
- A master-master MySQL replication model is used.
- The Linux clustering heartbeat was used to failover using virtual IP addresses.
- All users were migrated over without service interruption.
- Postgres was removed.
- During the migration images were served from NFS and MogileFS.
- Can easily add new machines and adjust workload.
- More highly available and is cheaply scalable