1.3 Evolution of TruCluster Server
1.3 Evolution of TruCluster Server
While we will not delve into the complete history of the clustering of computer systems – we'll leave that for another book – we will provide a brief history of clustering as it pertains to the evolution of the TruCluster Server product.
In 1982, Digital Equipment Corporation (Digital) – or as many users still fondly remember as DEC – introduced the first commercially viable cluster: the VAXCluster. What made the VAXCluster such a success was that it was technologically the most complete general-purpose cluster on the market. It was a full feature implementation of a SSI systems cluster and, as many would say, "very cool stuff."
Later, as Digital started producing Alpha AXP based VMS systems, they extended the capabilities of VAXCluster to allow for a heterogeneous mix of Alpha AXP and VAX based systems. The product name was also changed from VAXCluster to OpenVMS Cluster to reflect the heterogeneity of the product and the inclusion of the new POSIX open systems standards into VMS.
In 1994, Digital announced the first commercially available UNIX based cluster – the DECsafe Available Server Environment (ASE) version 1.0. DECsafe ASE was a failover cluster but instead of using a cluster interconnect for intra-cluster communications, it used the existing TCP/IP based network. Access to common storage was the initial paradigm with DECsafe ASE. See Figure 1-1.
Figure 1-1: ASE-style Cluster
Over the next couple of years, DECsafe ASE was improved to support additional Alpha-based systems and to add greater functionality in line with customers' demands and expectations for the product. This also provided an opportunity to create a solid foundation for the next step in the evolution of clustering on Digital UNIX. See Table 1-1, Cluster Chronology.
| Cluster Choronology | |||
|---|---|---|---|
| Date | Cluster Software | Operating System | Notes |
| 1983 | VAXcluster | VAX/VMS | The VAXcluster and VAX/VMS were renamed to the OpenVMS Cluster and OpenVMS respectively when ported to the Alpha AXP processor in the early 1990's. OpenVMS and the cluster software continue to be actively developed and supported. |
| 1994 | DECsafe ASE version 1.0 | DEC OSF/1 version 2.0A | |
| DECsafe ASE version 1.1 | DEC OSF/1 version 3.0A | ||
| 1995 | DECsafe ASE version 1.2 | DEC OSF/1 version 3.2A | |
| 1996 | DECsafe ASE version 1.3 | Digital UNIX version 3.2D and 3.2F | DEC OSF/1 is renamed to Digital UNIX. |
| TruCluster software version 1.0 | Digital UNIX version 3.2E and 3.2G | ||
| TruCluster Available Server Software version 1.4 | Digital UNIX version 4.0A and 4.0B | ||
| 1997 | TruCluster Available Server Software version 1.4A | ||
| 1998 | TruCluster Available Server Software version 1.5 | Digital UNIX version 4.0D and 4.0E | Compaq Computer Corporation purchases Digital Equipment Corporation. |
| 1999 | TruCluster Available Server Software version 1.6 | Tru64 UNIX version 4.0F and 4.0G | Digital UNIX is renamed to Tru64 UNIX. |
| TruCluster Server version 5.0 | Tru64 UNIX version 5.0 | TruCluster Server version 5.0, was a VERY limited advanced release. | |
| 2000 | TruCluster Server version 5.0A | Tru64 UNIX version 5.0A | |
| TruCluster Server version 5.1 | Tru64 UNIX version 5.1 | ||
| 2001 | TruCluster Server version 5.1A | Tru64 UNIX version 5.1A | |
| 2002 | TruCluster Server version 5.1B | Tru64 UNIX version 5.1B | Hewlett-Packard Company purchases Compaq Computer Corpotation. |
When Digital shipped the TruCluster Software version 1.0 product in 1996, it saw the introduction of MEMORY CHANNEL as the cluster interconnect. This was the next step towards achieving what OpenVMS Clusters already had: the SSI systems cluster paradigm.
What made the TruCluster Software version 1.0 product truly unique compared to DECsafe ASE was that it was the first UNIX-based cluster product to include support for cluster-aware applications. This support for cluster-aware applications basically allowed for the creation of SSI application clusters.
Late 1996 saw the creation of a new TruCluster (TCR) Product umbrella consisting of three functionally overlapping yet distinct products: TruCluster Available Server (ASE) version 1.4, TruCluster Production Server (PS) version 1.4, and TruCluster Memory Channel Software (MC) version 1.4.
ASE was the failover cluster product. PS was the natural extension to ASE and the SSI application cluster product. MC allowed users to write applications to take advantage of the new cluster interconnect – very attractive from the standpoint of high performance technical computing (HPTC). Of these three TruCluster products, PS and MC required the use of the MEMORY CHANNEL interconnect.
The next couple of years brought further evolutionary advances in the ASE, TCR, and MC software to provide support for new Alpha-based server hardware and new customer-centric features like shared Tape access, online service [2] modification, and Year 2000 Readiness.
1998 to 1999 was a watershed year in which we saw many things change, yet stay the same. Digital Equipment Corporation was acquired by Compaq Computer Corporation (Compaq), and the product name changed from Digital UNIX to Compaq's Tru64 UNIX.
In 1999, Compaq released TCR version 1.6, which offered many enhancements but nothing really new in terms of clustering technology. The enhancements included support for Enhanced Security (C2) [3], NetRAIN[4], NFS over TCP/IP, Switched Fibre Channel, and MEMORY CHANNEL 2.
Later that same year, Compaq quietly released TruCluster Server version 5.0 as a limited release to a select group of customers. TruCluster Server version 5.0 was the very first version of TruCluster Server to have SSI systems cluster features. From a UNIX perspective, this version of TruCluster Server was no longer evolutionary but revolutionary! It was revolutionary to be able to write a file from one server to a common cluster file system and then be able to read this same file almost instantaneously from another server.
2000 signaled the release of TruCluster Server version 5.0A and later TruCluster Server version 5.1 to customers. This was the first general release of TruCluster Server software that had SSI systems cluster features. As of the release of TruCluster Server version 5.0A, any new version of TruCluster Server software will release with any new version of Tru64 UNIX.
Tru64 UNIX version 5.1A and TruCluster Server version 5.1A was released in the fall of 2001.
That about brings us to the present (Summer, 2002). As of this writing, we expect the release of Tru64 UNIX version 5.1B and TruCluster Server version 5.1B in the fall of 2002.
[2]A "service" in the old ASE/TCR days is similar to a Cluster Application Availability (CAA) resource in TruCluster Server with the exception that you had to consider both the failover scripts and the associated storage for the service. CAA is covered in Chapters 23 and 24.
[3]C2 is a security level for computer systems and is defined by the U.S. Computer Security Center's "Orange Book."
[4]NetRAIN (Redundant Array of Independent Network interface controllers) is discussed in greater detail in Chapter 9.
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