Samba Clustering

Samba enables Linux servers to act as file and print servers for Windows based clients. LifeKeeper allows the recovery of Samba file and print servers when a hardware or application failure occurs.

Samba Failover

The Samba Recovery Kit provides a mechanism to recover protected Samba file and print shares from a failed primary server onto a backup server. LifeKeeper can detect failures either at the server level (via heartbeat) or resource level (by monitoring the Samba daemons, or IP resources) so that control of the Samba resources is transferred to a backup server. Other Samba services may coexist on a LifeKeeper server.

As with many other LifeKeeper configurations, it is possible to either use shared storage, or use the data replication option, or both.

Shared Storage

This requires some form of external SCSI / NAS / RAID array, which is connected to all servers in the cluster. The storage unit itself should be configured to provide redundancy providing fault tolerance at the data layer.

Data Replication

This is a more economical option for smaller installations, where (generally) a private network is used between a pair of servers to replicate data over. This allows for a lower cost initial solution (reduced hardware costs), yet giving a high level of reliability.

Disaster Recovery

The other advantage of Data Replication is that there is no limit to the distance seperating the machines (as long as sufficient bandwidth is available), this allows for a relatively easy setup and configuration of a disaster recovery solution.

Shared Storage and Data Replication

This gives the scalability of shared storage on the local network, as well as the power of data replication for use across a local, or wide area, network - providing good performance and offsite disaster recovery.

Data Replication - removing the requirement for Shared Storage

Once data is written to disk, LifeKeeper data replication will mirror that data to a remote server. This ensures that the data is up to date in the event of a server or a disk failure. The SAMBA recovery kit then enables the switchover to a backup server.

Samba Resource Hierarchies

A typical Samba hierarchy will be comprised of a Samba resource, one or more file system resources, one or more IP resources, and possibly a print services resource. An example of a resource hierarchy protecting a Samba file and print share in an active/active environment is shown below:

In this example, ServerA protects file share /Fshare-A; ServerB protects the file share /Fshare-B.

In addition, ServerA protects the print share /lp_publicprinter; ServerB does not protect a print share.

Original Source: www.openminds.co.uk