Our tests of Novell's SuSE Linux Enterprise Server Version 9 - we tested revision 9.1 of the server software - show it to be polished, faster and supporting a wider breadth of applications than previous versions. These advances are underscored by improved administration tools, compatibility with several CPU configurations, and connectivity with Novell-based add-on management and policy enforcement applications.

This version of Linux - which earns our Best Buy designation - could make Windows administrators who are still hesitant about widespread Linux deployment to take serious notice.

Organisations using Microsoft's ASP.Net application infrastructure can port their applications to SLES 9 via the new SuSE Linux software developer's kit. Novell's acquisition of Ximian brings a C# compiler to SLES 9 and compatibility with ASP.Net Web applications.

Installation and configuration
SLES 9 performs numerous dependency checks at application installation time via a revamped administrative interface, still called YaST (Yet Another SetUp Tool). Adding server applications and updates is simplified and safer. SLES 9 contains many server service-oriented applications, such as DHCP, PostFix Mail and DNS, as have prior editions. This isn't a case of distribution becoming bloated, but the basic expectation set by Novell is that this server operating system fits several network and application server profiles.

Hardware detection has improved over previous SuSE Linux versions (see SuSE Linux 8.0 test). We installed it on several typical server platforms and found that when a hardware vendor supplied a driver kit, detection improved dramatically. But when they didn't supply the kits, we received odd errors. SLES 9 displayed incorrect default kernel choice information when we installed natively on an HP DL360G3 dual-CPU server, but actually installed the right kernel. We found no abnormalities in hardware compatibility.

The default server applications installed comprise a minimal set of programs identical to all three supported CPU platforms. Happily, run levels and defaults initially were installed with the most conservative possible settings.

We applaud this methodology, as it forces administrators to choose what services will be available rather than turning them on automatically and causing potential security or network services interaction problems. Updated applications don't affect already-chosen defaults or subsequent security-oriented settings. Subsequent downloads can be spawned manually, or automatically through the YaST Online Updater server, citing either an internal or SuSE.com update source.

Most installers will choose more applications than the default settings provide, however. Making additional choices via YaST before or after installation - such as adding FTP support - puts in the desired application and checks dependencies so other libraries or components are also correctly chosen.

You can easily build secure server images for distribution to other servers on the network.

Testing performance
Our performance tests - run across four server platforms - comprised a series of Web usage profiles, including:

  • Maximum number of connections.
  • Total sustained connections.
  • Transactions per second.

SLES 9 bested all server operating system products we've tested in the Intel/AMD categories (see table). As in previous tests, only default Apache and operating system settings were used in an IPv4 environment.

Test results

Test/HardwareMSI AMD/64 (1 CPU)Micron/NetFrame server (2 CPUs)HPDL380G3 server (2 CPUs)HPDL580G2 server (4 CPUs)
Maximum open TCP connections/sec84,38892,20396,551104,660
Maximum TCP connections/sec1,8841,9922,0262,421

The increase in performance is largely due to the 2.6.5 Linux kernel SLES 9 is built upon. The generic AMD64 server performance using a single CPU is outstanding, besting all previous operating systems tested, save one instance. This is especially noteworthy because past operating system tests were conducted on a dual-CPU Intel architecture. The startling increase in transactions per second also speaks to better kernel I/O as implemented in SLES 9 and gives an indication of Web transactional I/O of static pages.

Managing SLES 9
System management provided by YaST is the core, GUI-based management application. Administrators can manage Apache, Samba, Lightweight Directory Access Protocol (LDAP), Network File System, users, package/application installation, the firewall and most other administrative/management settings. YaST compares favourably with Windows Server management, albeit without strong "wizards" that Windows Server editions offer. Those desiring the command-line interface method can manage elemental services, such as DNS, LDAP, DHCP and Apache.

SLES 9 also can create multiple instances of Linux within the same hardware (similar to virtual machines) through the User Mode Linux (UML) feature. We spawned multiple sessions with UML that shared media and hardware resources using a method vaguely similar to VMWare ESX Server. The UML virtual machines don't have the same depth of control that VMWare offers, but they do let you partition resources (CPU, disk, identity, applications and hardware) that can permit logical isolation of desired resources.

SLES 9 can partition sessions via UML, so an application hijack can be contained by the permissions, password or security established for that session, rather than for the system as a whole. This means multiple instances of applications, such as LAMP (Linux/Apache/MySQL/Php-perl) sessions, can be hosted more safely.

In turn, the UML instances can be coupled to the security established through the certificate authority and remote sessions via OpenSSL and VPN capabilities session policy managed through YaST.

Other features
Server connectivity enhancements include the Novell/SuSE exclusive implementation of Service Locator Protocol (SLP), similar to and compatible with the Apple-championed Rendezvous Protocol. We found SLP simple to use, although certain Layer 2/3 Ethernet switches must be reconfigured to use it. SLP enhances directory network service resource lookup and is a good alternative to DNS and Session Initiation Protocol for served applications.

Several features make SuSE a Clear Choice winner. It outperforms the competition. Its compatibility list is strong. Even though there are a few exclusive items, it would take quite some time to assemble the open source components Novell has put in the SLES 9 framework and make them all run together cohesively. Moreover, the YaST improvements will give GUI comfort to those who don't want to memorise server application variants. The combination gives SLES 9 far wider appeal than previous versions.

Henderson is principal researcher for ExtremeLabs of Indianapolis. He can be reached here.


Test methodology
We tested SuSE 9.1 i386 version on three servers: an MPC/NetFrame 1U rack server with dual 3.06MHz Xeon processors, an HP DL360G3 with a similar, and an HP DL580 with four 2.4GHz CPUs.

We also tested the AMD64 version on a 'whitebox' system consisting of a 2.8GHz AMD64 CPU with an MSI motherboard, 4GB of dynamic RAM, and Serial Advanced Technology Attachment disk drive.

We tested all versions on a network consisting of a Gigabit Ethernet switched backbone and checked logon compatibility with the following server operating systems: Windows 2003 Enterprise Edition, Apple OpenDarwin OS/X 10.3, Red Hat Linux Enterprise 3.0, NetWare 6.5, NetBSD 1.6.0, and Windows NT Server 4.0, as well as Apple OS/X clients (Powerbook G4, G4 desktop, Titanium G4), Windows XP/2000/98SE clients (Compaq Presario 700US notebooks, IBM ThinkPad 600E notebook, Sony Vaio notebook, several HP/Compaq desktops and several whitebox desktops); GNU/Linux 2.4.17 kernel Mandrake 9, Xandros 3, Debian Potato clients (Presario 700US, several whitebox desktops).

We examined version continuity among the distribution applications for each of the three tested platforms (i86, AMD64, and PPC). We also tested version levels among the applications, as well as the current vs. shipped level of several service applications, all of which were behind but patched at our installation update time.

We used Spirent Communications' WebAvalanche benchmarks to conduct our Web performance tests. We ran tests to determine the number of transactions processed per second, as well as the maximum number of TCP connections per second and found them to be good for this class of processor/speed.


With top performance, strong compatibility and wide appeal for a number of circumstances, SLES 9.1 is a worthy Best Buy winner.