Linux Much Cheaper Than Unix, But Only for Certain Workloads

by Kristin Palitza

Linux on Intel-based servers is a viable alternative to RISC/Unix servers for certain workloads, due to its total cost of ownership (TCO) being significantly lower than for Unix servers, according to a new study just released by researcher International Data Corp. Those findings, it warns, are true for particular workloads, but not for all. IDC compared Internet/intranet/extranet and collaborative workloads--two popular Linux workloads--on Linux and RISC/Unix platforms for the TCO study; analysts stressed the point that other workloads are likely to bring less impressive TCO benefits.

A few years ago, Linux was not as broadly deployed as Unix, and the availability of Linux skills used to be limited so that people expected staff costs to be higher for Linux than for Unix, explained McLarnon. Now firms realize that Unix skills can be relatively easily leveraged for Linux, since both systems are similarly built. "This means that if a shop already runs Unix, it can bring in Linux without much costs," McLarnon said. Additionally, the next generation of IT staff will be well trained on Linux, he added.

Those low staffing costs could come as a blessing to Linux, since companies feel enormous budget pressure due to the economic downturn, McLarnon reckoned. Companies have to work with fewer staff and smaller budgets--and this is what Linux has to offer.

In the case of Internet/intranet/extranet infrastructure workloads, Linux delivers a 1.8 to 1 cost advantage over RISC/Unix and a 5.5 to 1 cost advantage for collaborative workloads, IDC said. The TCO for an infrastructure workload on Linux, for example, is $377 per year per user for 1,000 supported users, compared to $684 on RISC/Unix; Unix servers cost 80 percent more than Linux servers. For a collaborative workload, the cost difference is nearly six-fold, with Linux reaching a TCO of $255, against RISC/Unix with $1,407.

The infrastructure workload includes internal and external firewall operations, Web serving and Web caching, as well as B2B and B2C e-business operations. The collaborative workload is based on shared messaging and directory platforms consisting of email, calendaring, scheduling, shared folders and databases, threaded discussions, and custom application development.

IDC calculated TCO based on the cost for acquiring hardware and software combined with all staffing costs related to acquiring, maintaining, and removing IT assets. It compared the TCO for Linux on IA-32 systems with that of proprietary RISC/Unix systems from several leading vendors. Although different on a hardware level, the operating environments were similar in terms of capabilities, user interfaces, command line interfaces, commonly used shells, similar scripting languages, similar utility and infrastructure support, and an increasingly compatible set of application programming interfaces, the researcher said. IDC interviewed 142 IT managers of companies with more than 100 employees and an average of $2.4 billion in annual revenue across multiple industry sectors, such as manufacturing, business services, telecommunications, government, education, healthcare, transportation, retail, finance, insurance, utilities, non-profit, and other services.

"Linux on the Intel platform has emerged as a real alternative to RISC/Unix for enterprise computing," the IDC analysts said. However, Linux is not on its way to replace Unix, either. "We didn't see many people pulling Solaris out, but firms test Linux and get good results," McLarnon said. Companies will run a mixture of platforms, for example larger Unix servers combined with Linux as gateways and front-end servers, he reckoned, very few will run a pure Linux environment. "Linux is growing year over year, but we don't see Linux making Unix go away," Gillen said.

Enterprises should pilot Linux servers first, to verify its potential for their IT systems, and then create a strategy for long-term deployment, IDC recommends. This may include expanded application or infrastructure workloads supported by new systems or migrating some existing workloads over to new systems or redeployed systems running Linux. However, the researcher warns companies not to be too euphoric jumping on the Linux bandwagon. Firms adopting Linux should carefully consider where to deploy it and well align requirements of workload, IT capabilities, and Linux virtues such as cost, performance, reliability, manageability, applications availability, and vendor support.

Today, many companies are already testing Linux and the pilots go well, according to McLarnon. "Firms like Linux because of the lower cost, of course, but also because of its reliability, performance, stability, and manageability," he said.

"Beyond directly lowering costs for workloads on Linux, visible deployment of Linux also provides IT managers with a powerful tool for negotiating more favorable prices from other suppliers of hardware and server operating environments," the IDC analysts reckoned. If firms can get well-working open source for low cost or free, there is little reason to pay high prices for proprietary technology. However, TCO is only one factor among others in the decision process for an operating environment, next to applications availability, IT staff expertise, experience, and comfort.

Additionally, the study found that the average RISC/Unix shop was running far more systems to support its workload than the average Linux shop. RISC/Unix was running 12.2 servers on average to support Internet/intranet/extranet infrastructure workloads, whereas Linux was only running 3.1 servers. However, RISC/Unix supported an average of 7,597 users for such a workload, while Linux' user-per-workload average was only at 1,150. IDC said the low user number is based on the fact that Linux is a relatively new OS to larger corporations, and therefore did not find broad user adoption as this stage. The number also indicates the higher scalability of RISC/Unix.

The participants of the study were mainly using a pre-2.4 kernel Linux version, however, and Gillen expects the Linux 2.4 kernel to provide better scalability through memory support of up to 64 GB of main memory and 4 GB of memory per process. Linux 2.4 also includes improved SMP scaling (up to eight-way servers, with four-way support being about as good as Windows), large file and file system support, increased device support, and improved networking features, such as high performance TCP/IP.

In the case of collaborative workloads, RISC/Unix customers run an average of 11 servers, compared to Linux customers surveyed by IDC using only 4.1 servers on average. However, the user-per-workload ratio was nearly equal for both systems in this constellation, IDC said. RISC/Unix servers supported an average of 4,802 users, and Linux servers supported 4,558 users. Therefore, Linux clearly gives a better benefit in this scenario, since "supporting an equal number of users with fewer systems contributes to the TCO advantages," IDC stated.

The researcher also found that staffing costs for collaborative workloads on Linux ranged from 50 percent down to an incredible 6 percent of the staffing cost associated with RISC/Unix servers, describing those numbers as "dramatic" compared with more competitive results for Internet/intranet/extranet workloads.

Splitting up the TCO for Internet/intranet/extranet infrastructure workloads in different cost segments, IDC discovered that the disposal of a Linux server is ten times less expensive than of a RISC/Unix server. The reason for this huge difference may be attributable to the widespread use of Intel-based servers, which are recycled and used in different locations inside companies.

The procurement of a Linux server is also much cheaper than that of a proprietary RISC platform, IDC said. Whereas customers have to spend only $7 per user per year per 1,000 users for a Linux system for Internet/intranet/extranet workloads, they have pay $31 for RISC/Unix. The lower costs are "presumably [...] related to the standard nature of IA-32 hardware," the IDC analysts reckoned.

Administration costs on Linux servers are roughly half of those of a RISC/Unix server, IDC further said, because of more complex configuration and multiple workloads on RISC/Unix, compared to more simplistic Linux workloads. In other areas, such as network management, database management, user support, upgrades or backups, both systems are "remarkably consistent" for Internet/intranet/extranet workloads.

In contrast, database management costs for collaborative workloads differed widely on Linux and Unix servers. They were considerably higher for Unix platforms ($189 per year per user for 1,000 users) than for Linux ($15). Linux is about 12 times cheaper than Unix for two reasons, First, the more comprehensive use of Linux improves TCO on database management; second, Unix systems are more likely to have Lotus Notes/Domino installed, which creates a second DBMS environment to manage. The findings also indicate that Linux and Unix are not functionally equivalent. "It's like comparing public transportation to a Mercedes," McLarnon said. However, not every firm has complex workloads, and for those with basic requirements Linux offers a good package for a much lower price, he added.

Moreover, Unix systems show much higher network management costs than Linux, $214 per year per user for 1,000 users and $12 respectively, because Unix supports more complex workloads, and larger Unix systems are often part of a more complex infrastructure, which relates to higher network management costs, IDC found.

In conclusion, IDC believes that the TCO benefits of Linux in supporting Internet/intranet/extranet and collaborative workloads are likely to boost the adoption of other workloads broadly supported by open source applications--such as firewall and security--and with increasing adoption, TCO benefits will grow further. Small wonder the Unix server vendors are scrambling to present a credible and differentiated Linux strategy.