Open Source And Open System Leverage

Part of PostPath's Lean Infrastructure approach is to adopt and support both standard interfaces (including protocols) and modular, standard components joined together in the simplest practical architecture.

Open Source Components

Open Source components leveraged in the PostPath system include:
  1. Linux (http://www.kernel.org/). The base operating system for the server. The PostPath server relies particularly on the advanced networking capabilities in the 2.6 kernel
  2. Samba (http://www.samba.org). Samba provides windows-server domain presence (responds to machine-name/NetBIOS queries, etc.). We also think there may be interesting opportunities at some future date to provide Active Directory™ capabilities within Samba that would enable a network of Samba servers to act in place of, or co-exist with, a network of domain controllers i.e. to provide Active Directory™ service for Exchange™, the PostPath Server™, and Outlook™ users, though this is not supported today(3)
  3. Postfix MTA (mail-transport-agent) (http://www.postfix.org/) is responsible for queueing and routing of messages. PostFix is one of the most widely used Internet and enterprise MTAs. PostPath's addition of ESMTP support enables PostFix to receive emails directly from the Microsoft Exchange MTA; PostPath Server™ also enables ESMTP-SMTP translations to enable use of standards-based virus or spam filters and standards based archiving solutions
  4. Any open-source and/or standards virus, spam or other filter or archiving solution can be used with the PostPath Server™, thanks to point three above. Almost all filtering and archiving products support standard SMTP.
  5. Open-source AJAX webclient, integrated to use the PostPath Server as the "back-end" server. PostPath has ported and integrated the open-source web client developed by Zimbra, Inc.
  6. Linux-filing systems for high performance, especially XFS (http://oss.sgi.com/projects/xfs/) and Reiser4 (http://www.namesys.com/v4/v4.html). Commercially packaged storage also works well, mounted using NFS (http://nfs.sourceforge.net/)
  7. Open source file replication technologies, notably DRBD (http://www.linux-ha.org/DRBD), NBD (http://nbd.sourceforge.net/) and ENBD (http://www.it.uc3m.es/~ptb/nbd/). Commercial file-system replication technologies can also be used in the same kind of way. Replication allows a live, real-time or near-real-time (i.e. asynchronous) copy of the PostPath Server's™ store to be maintained in case of server failover or to ease backup or other administration
  8. Failover from linux-ha (http://www.linux-ha.org/HeartbeatProgram). These technologies have been integrated to enable hot or warm failover of the PostPath Server™

Notes

For components that run alongside the PostPath code, the PostPath install program installs (if not already installed) and correctly pre-configures the component for operation with the PostPath Server™.
  1. Where open source components are modified by PostPath, the modified version of the source is published to conincide with product delivery.
  2. To avoid confusion, we should mention that the core of the PostPath Server™ is a commercial product, not an open source project.
  3. The Samba team has of course already been working on many important aspects of domain controller functionality.
PostPath would like to acknowledge the huge contribution of the open source community to the enabling of a real alternative.