Hardware Today: Apple Server Snapshot
February 6, 2006
Although not noted for its server lineup, Apple Xserve has made significant strides over the past two years. And this year, Apple surprised the world when it announced a shift to the Intel Core Duo processor. The move has been implemented at the PC level already and will be added to Xserve by the end of the year.
"The new Core Duo chip from Intel is two to three times faster than its predecessor," says Apple CEO Steve Jobs. "Both cores of the new dual-core Intel chip are faster than the G5 processor."
Although a small player compared with HP, Dell and IBM, Apple seems to know which way the server wind is blowing. As a result, it has made significant changes in Xserve over the past year in hardware and software as well as in added storage capabilities in the form of Xsan for storage area networking.
According to Alex Grossman, Apple's senior director of hardware, server and storage, there are four basic Xserve configurations. They differ in terms of processing speed, RAM and other specifications. The Single Processor Xserve is a 2.3 GHz, 64-bit PowerPC G5 1U server. It comes with 1 GB of RAM, 80 GB in serial ATA (SATA) drives and the OS X operating system. It costs $2,999. The Dual Processor Xserve unit has the same basic specifications as the one-way system, but this time with two processors. The cost is $3,999.
The Cluster Node, on the other hand, is a compute-optimized dual-processor model. It has similar specs to those of the Dual Processor Xserve, but only 512 MB RAM. It is priced at $2,999.
The Ultimate Xserve is the top of the Apple line. It has a customized configuration and the maximum amount of storage capacity available (i.e. it has anywhere from 2 GB RAM all the way up to 6 GB RAM, three 500 GB SATA drives and can run the unlimited client edition or Mac OSX server maintenance program for $7,048).
Xserve's allure is further heightened by a matching RAID box that adds as much as 7 TB in a 3U box, up from the 5.6 TB available in the March Xserve RAID release. Grossman says that works out to about $1.86 per GB. And to enhance storage performance, Apple just added a new hardware RAID card to supplement the RAID software built into the Tiger operating system.
Each Xserve RAID box has up to 14 hard drives and can be arranged in RAID 0, 2, 3, 5, 10 as well as the more exotic configurations like RAID 30 and 51. RAID 5 delivers 800 GB of space. RAID 0, on the other hand, expands the storage capacity to 1.2 TB per unit.
"A lot of customers don't need the extra RAID box, as the Xserve alone gives them all the storage they need," said Grossman. "When it comes to tier-two storage, it's hard to beat Xserve RAID for cost effectiveness."
Hardware Tuneup, Software Overhaul
On the hardware side, the advances to Xserve are relatively modest. Processor speed has been increased to 2.3 GHz, RAM has doubled to 16 GB and hard drive size is up to 1.5 terabytes. Further, there is now RAID-protected storage available in its 1U box.
But it's on the software side that Xserve has undergone the biggest overhaul. Based on customer surveys, the company said it has greatly expanded the inherent server capabilities of the Xserve machine. As well as being a general-purpose server, it has Apache for hosting secure, high-performance Web sites as well as other functions built in such as file sharing, blogging and system updating.
"The new version of the Mac OS known as Tiger Server can now operate as a software update server and as a Web blog server," says Grossman. "Customers told us they wanted to update all Mac-based servers over the network. We built that into the OS so they can have one server that does multiple functions."
Take the Web blog server, for instance. Users often need to buy specific software to set up an existing server for use in Web blogging. With Apple Xserve, this functionality is already built into the OS. Similarly, instant messaging (IM) comes with the server software. iChat, Apple's IM platform, is compatible with AOL and open-source IM systems. iChat can be used for secure instant messaging internally within the organization. As the chat is encrypted, outsiders can't get in.
Another new capability is Windows-compatible access control lists. Somewhat surprisingly, Grossman concedes that Windows really is better at least in this area.
"A Unix-based OS such as Apple doesn't have the inherent flexibility for file permissions that Windows normally offers," he says. "So we decided to adopt Windows compatible access control list."
To cater to the growing SAN market, Apple added a new file system called Xsan. The software works on a Mac OS X platform and provides multiple Xserve servers with concurrent access at the file level through Fibre Channel across the SAN network. Grossman reports that as of the second quarter of 2005, the company had shipped 76 petabytes of storage. About 40 percent of the total, he says, was in a mixed environment (i.e., Apple, Linux and Windows servers connecting to the Xsan-based SAN).
"Storage can be added, repartitioned and reassigned to several servers simultaneously," says Grossman. "Xsan is especially good for fast media screening of movies and does almost everything that a virtual file system (VFS) can do."
One of the selling points of an Xserve-Xsan environment is that it holds the potential to reduced storage overhead. When using a storage array and host bus adapter, for example, the cost of deployment can work out to be about three- to five-times less compared with other systems on the market, according to Apple's estimates. Say you are running an EMC storage array using an Emulex Host Bus Adapter (HBA) for around $1,500. The PowerPath software pathing software that allows you to balance across multiple FC ports so you get better throughput costs about $3,500. With an Apple setup, the storage software is about $1,000 per server license (about a third to a fifth of many alternatives), the HBA costs about $500 and the pathing software is included at no extra charge.
For a mixed OS environment, however, you have to factor in the cost of ADIC StorNext as the interface with non-Apple platforms. This ADIC software is a SAN file system for Windows, Unix and Linux. XSAN needs this software to run heterogeneous OSes.
"Everything can be run through Xsan," Grossman says.
Xserve RAID is now up to 7 TB a box at a $1.86 per GB. It is also optimized for Oracle 10g and can have multiple instances of 10g running in one 3U 14 hard-drive, dual raid controller storage box. In terms of SAN performance, a throughput of 380 Mbps can be achieved with dual 2 Gbps Fibre Channel.
The Core Duo is the centerpiece of Apple's server and PC roadmap. This chip is the first Intel product to use a new 65-nanometer process. This makes it possible to build transistors so small that a hundred could fit inside a single human cell.
While it's pretty easy for a chip maker to design a Level 2 cache dedicated to a single core, such as for the Pentium M processor, Intel's Core Duo processor has a new type of cache design that allows sharing by both execution cores. This fuels performance improvement and energy efficiency. In addition, it preserves battery life. The two cores work independently, and if only one core is used, the second core enters an idle state.
What does this mean for Xserve, Apple and its customers?
"The plan is to transition to the Intel processor by the end of this calendar year from today's IBM G5 2.3 GHz processor PowerPC processor," says Grossman. "It's the best way to improve performance."