Test: Apple Xserve

Apple’s new Xserve is fast and well equipped for network use.

What doesn’t come from Advanced Micro Devices, Intel or Sun; is based on open source practices; provides comparatively fast services for Windows, Mac, Linux and BSD clients; holds up to 720G bytes of stored disk data; and is just 1.75 inches tall? It’s Apple’s Xserve 1U server platform – now in its second iteration.

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Xserve is based on the PowerPC CPU running at a minimum of 1.3 GHz with up to two of these CPUs fitting into the 1U Xserve form factor. Instead of one disk channel, there are three ATA-133 channels and up to 720G bytes of disk in the server.

Apple’s operating system on this platform – OS X Server 10.2.5 – is built on the Darwin Branch of BSD, and is covered under the Apple Public Source License, which varies from the Open Source license that underlies Linux. The BSD heritage of Darwin means that users familiar with Unix, Linux and especially xBSD will feel at home, although there are many Darwin-specific GUI-driven applications that control traditional command-line administration applications.

Xserve is not a plain vanilla server that tries to compete on price/performance. Its extra features (such as independent disk channels, FireWire 800 and high-tech-touch hard drive bays) carry a high price tag. To its benefit, it has no user-license fee, connects a variety of operating-system client types, and delivers strong Web performance.

Performance

We subjected Xserve’s Apache Web server to the same suite of tests using Spirent Communications’ WebAvalanche software that we used to stress Windows 2003 Enterprise Edition with Microsoft’s Internet Information Server (see Windows Server 2003 review) and found performance was quite strong (see graphic).

The ATA-133 disk interfaces and drives in Xserve were comparatively fast in our testing, although internal RAID configurations seemed to take up excessive CPU time. A RAID Level 1 configuration slowed disk writes by as much as 5%, with 3% being typical. We also connected our Lexmark printer as an Unix Line Printer device and printed through Xserve with Apple, Linux/BSD or Windows clients with ease. (See How we did it ).

Setup

Xserve comes with a front bezel that is removed for rack installation, which can be done via a supporting frame,as we used, or a midchassis/double-rail installation. Xserve contains quite a bit of densely packed hardware, and therefore generates a lot of heat, and associated fan noise can be high.

There are two methods of initially activating Xserve’s software – via an Apple client networked to it (“headless”) or by outfitting the Xserve with monitor, keyboard and mouse. There is no HTTP interface for installation, so an Apple running OS X Server 10.2 or a USB keyboard/mouse and monitor is required. Secure Shell can be used for command-line-based applications but not for installation purposes.

The unlimited user license ships with Xserve at no additional charge. Xserve uses common Unix-derivative applications such as Samba and Common Unix Printing System, and these applications are controlled by Xserve server administration applications.

Several choices for file/print compatibility are offered at installation time. We were dismayed to find that upon initial installation more than 90M bytes in upgrades were required. We would have preferred that Apple ships a fresh system with all current updates. This leads to a possibly long download, installation and reboot time to make the server usable.

We tested the product’s Windows user management capabilities, which come via Samba. Apple’s version of Samba can be administered via Xserve’s graphical user interface. The System Manager application lets Xserve become the equivalent of a Windows primary domain controller or master controller.

At the core

Xserve supports up to 720G bytes per server in four drive bays, and each bay is connected to a separate ATA-133 disk channel, instead of the drives sharing a single channel. Although there are few internal RAID options, Apple markets an Xserve RAID subsystem that’s connected to Xserve via an optional independent Fibre Channel controller.

Xserve uses the Hierarchical File System (HFS), which provides backward compatibility with Mac OS/9 and earlier clients. With the introduction of OS X Server 10.2.2, Apple offers the option of a journaled file system. I/O transactions in such systems are highly detailed, so it is easy to recover from a system halt.

Journaling isn’t turned on by default with Xserve. It adds nominal disk overhead, but does seem to have an effect on throughput, increasing disk write times considerably. We launched a script that wrote a 100M- byte file concurrently from six workstations before and after HFS journaling was activated. Journaled file-system execution time increased from 42 seconds (nonjournaled) to 61 seconds (journaled).

Apple uses a 66-MHz/64-bit PCI bus in this platform. Xserve comes with three bus slots. A Gigabit Ethernet port that’s in addition to the Gigabit Ethernet port on the motherboard takes up one of the bus slots.

Also included are IEEE 1394/FireWire 800 connections. While FireWire – a serial device interface bus running at near-gigabit speeds – isn’t used much in the Windows world, it’s often used in Macintosh and Sony computers, as well as for video devices, portable disk drives, and occasionally as a network transport. Keyboard and mouse connections to Xserve are strictly via USB (1.1).

A graphical System Monitor application tracks internal configuration of one or many Xserves in a network. Alarm conditions are noted, and even things such as fan speed and system temperature are recorded.

Server security

Apple supports an IP firewall. The firewall lets you select which part of the NetInfo directory service domain is visible, and lets you block User Datagram Protocol in port ranges. Apple offers stateful packet inspection but not advanced firewall features.

Apple bundles three applications: NetMinder Ethernet, which captures, decodes, and provides rudimentary analysis on network I/O; LAN Surveyor, which is a network mapping/GUI-based asset management package; and CyberGauge, an SNMP monitoring package that’s limited to Xserve in the limited bundled edition.

NetInfo directory services

OS X Server uses NetInfo to consolidate and distribute directory services information. In Apple’s model, each machine has its own NetInfo directory database, which can be forward-referenced to a higher level, such as a server. Apple purchased PADL Pty., and its Lightweight Directory Access Protocol-NetInfo bridge to provide a link between NetInfo and LDAP services.

We set up a NetInfo domain, then established one server as a root domain, while the other three servers supported subsidiary domains. During this process, we also established the root server as a Windows primary domain controller (PDC). We discovered that the PDC control, done in conjunction with Samba, needed to be installed on a quiet network, with all Windows 2000+ clients turned off, as Win 2000 clients and a Win 2000 Server would try to force an election of themselves as a master domain controller. We later found a registry hive for Win 2000 and XP that prevent them from asserting control over the PDC services in Xserve. Synchronizing the domains, essentially grafting domains together, was simple.

Overall

Xserve hosts many services, from file-and-print for a variety of client types. While decidedly Apple, Xserve puts to shame many of the Linux distributions available by tying together the diverse number of applications that are needed to administer an equivalent Linux server into a simple, GUI-driven interface. Xserve plays well in a Windows network, but also accommodates a variety of network constructions – all from a tight 1U package.