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 we've tested.Our tests of\u00a0Novell's\u00a0SuSE 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\u00a0applications\u00a0than previous versions we've tested. These advances are underscored by improved administration tools, compatibility with several CPU configurations, and connectivity with Novell-based add-on\u00a0management\u00a0and policy enforcement applications.This version of\u00a0Linux\u00a0- which earns our Clear Choice Test designation - could make Windows administrators who are still hesitant about widespread Linux deployment to take serious notice.How we did it Archive of Network World reviews Subscribe to the Product Review newsletterOrganizations using Microsoft's ASP.Net application infrastructure can port their applications to SLES 9 via the new SuSE Linux software developers kit. Novell's acquisition of Ximian brings a C# compiler to SLES 9 and compatibility with ASP.Net Web applications.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\u00a0SuSE Linux 8.0 test). We installed it on several typical server platforms (see\u00a0How we did it) 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\u00a0security\u00a0or 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 performanceOur performance tests - run across four server platforms - comprised a series of Web usage profiles, including:\u2022\u00a0 Maximum number of connections.\u2022\u00a0 Total sustained connections.\u2022\u00a0 Transactions per second.SLES 9 bested all server operating system products we've tested in the Intel\/ Advanced Micro Devices categories (see graphic). As in previous tests, only default Apache and operating system settings were used in an IPv4 environment.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 9System 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\u00a0firewall\u00a0and most other administrative\/management settings. YaST compares favorably 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 do let you partition resources (CPU, disk, identity, applications and hardware) that can permit logical isolation of desired resources.SLES 9 also 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. SLES9 OVERALL RATING 4.63 Company: Novell Cost: Single server with up to two CPU's is $350 annually. Single server with up to 16 CPUs is $900 anually. Pros: Improved management; great performer, flexible hardware and software support. Con: Some minor installation irritations. The breakdown \u00a0 \u00a0Installation\/integration 25%\u00a0 4.5 Performance 25%\u00a0 5 Management\/administration 25%\u00a0 4.5 Security 25%\u00a0 4.5 TOTAL SCORE\u00a0 4.63 Scoring Key: 5: Exceptional; 4: Very good; 3: Average; 2: Below average; 1: Consistently subpar 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.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\u00a0Session Initiation Protocol\u00a0for 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 memorize server application variants. The combination gives SLES 9 far wider appeal than previous versions.