A look at Apple's new G5 Xserve and Xserve RAID

For the past two weeks I have been the proud user of Apple's newest assault on the enterprise: a dual-processor Xserve G5 and an Xserve RAID. For those of you who already have a G4 version of the Xserve, you will still be in awe of this box. For those who have never had one, keep a chair handy to faint into.

First, let me talk about some of the basic specifications of this new server, which is only now beginning to trickle into the hands of buyers.

In order to accommodate the higher temperature output of the G5 processors, the new G5 Xserve was designed with only three drive bays instead of the four offered in earlier G4-based Xserve. That provides room for the venting ports. To offset that change, however, Apple's engineers wisely increased the maximum size of the bay drives to 250GB, so the server can provide 750GB of storage, a modest jump above the 720GB offered in the G4 version.

Apple also added new sensors to show the temperature of the room air coming into the box, the temperature of the processor and the temperature of the air being exhausted. Looking at those sensors shows that the vent ports improve the airflow dramatically. The result: The new server stays substantially cooler than its predecessor. That's noteworthy because the cost of powering and cooling a data center is rising with the increase in energy prices, so device heat output and power consumption are increasingly significant factors in product selection.

You can see the multiple points of temperature monitoring here.

A look at Apple's new G5 Xserve and Xserve RAID
fig 4 box temp monitoringfig 5 processor temp

The Apple Xserve sports 8GB of 400-MHz ECC RAM, a 128-bit memory bus and more than twice the overall throughput of an Intel Itanium 2 system. Yet a fully loaded server running at maximum CPU and disk output uses less than 300 watts and outputs less than 1,000 British thermal units. That's another variable managers should add into their cost of ownership calculations when evaluating the Xserve. The chart below shows the details:

A look at Apple's new G5 Xserve and Xserve RAID

My review can be summed up easily: The Xserve is fast -- really, really fast! This box screams, yet it's incredibly quiet in operation. Although it has eight fans, all run quietly, and only when necessary. I could put this on my desk and not hear any noise except for the gasps of fellow techies when they see it.

The inside of the G5 Xserve shows Apple's usual attention to detail. My particular configuration has 4GB of RAM and dual 2-GHz processors. Both Ethernet ports are on the motherboard, leaving the PCI slots for Fibre Channel cards and a display card. The rest of the ports are unchanged from those on the slot loading G4. Also included in the box are two power plugs: a long one and a shorter one for connecting to rack-mounted power supplies. It's a nice touch.

A look at Apple's new G5 Xserve and Xserve RAID
fig 1. G5 Xserve Dual Processor

Here you can see the server monitor output. The G5 Xserve requires Server Monitor Version 1.1.12 in order to read all of the sensors that are built in, so make sure to get that version if you are using an older box to administer and monitor. You can see from the screenshot below all the additional monitoring points on this new server.

A look at Apple's new G5 Xserve and Xserve RAID
fig 2. server mon main page

In this shot you can see the detail on the power systems of the G5 Xserve. Wide variances in power can indicate impending component failure or be the cause of one. In this case, more information is good.

A look at Apple's new G5 Xserve and Xserve RAID
fig3. power monitoringfan monitoring

The RAID storage unit

Now, let's look at the Xserve RAID unit. This unit is well thought out, an enterprise quality workhorse that provides multiple points of fault tolerance and hot swappability. The cost per gigabyte is also the lowest of all enterprise-quality RAID vendors, yet the device is just as solid and stable as its competitors. It can be used in a Windows Server Message Block share, Unix Network File System and, of course, Apple File Sharing.

The 14 drive slots are hosted by two controllers, one for bays 1-7, the other for bays 8-14. You can see from the photo below that the network interface card is integrated with a Fibre Channel connector for direct connection to the Xserve. There is also an Ethernet port on the card used for monitoring and management of the RAID server. On the top left is the battery for backing up the disk cache. This means that in the event of a power outage, all disk operations could complete and the system would not lose any data. At the bottom is the removable power supply, which has a little catch that holds the plug in place and prevents it from accidentally being pulled out. In high-traffic studio environments, this might seem trivial, but it's a welcome feature that will keep much hair in the head of the support engineers.

A look at Apple's new G5 Xserve and Xserve RAID
Exploded back of RAID server
A look at Apple's new G5 Xserve and Xserve RAID
Plug catch closeup

Operation of the RAID unit is, not surprisingly, very Apple-like. I just plugged in the power, connected the SFP Fibre Channel plugs and fired up the RAID unit. I connected the Ethernet plug to my network switch and launched the RAID admin application. My operating system came with RAID Admin 1.2, which has a few bugs, so I downloaded the newer Version 1.3 and applied the firmware patch to the RAID unit.

Hint: The RAID admin update installs the update in Utilities/XRAID update, rather than in Applications/Server, so you will need to manually move the 1.3 admin over. Using the admin application you can manage the RAID network interface operations. In the picture below I've set the NIC to use the DHCP protocol, but you can also use a static IP.

A look at Apple's new G5 Xserve and Xserve RAID
NIC config

The next step is to decide how to configure your storage. RAID Level 5 requires at least three drives, and you will lose about 25% of your total capacity, but it provides fault tolerance. If a drive fails, just replace the drive and the RAID controller will rebuild the lost info form the parity data stored on the other drives. I chose RAID Level 0 that stripes the data on all drives and is the fastest, but it provides no backup. This is the ideal configuration when you are working with video applications and have a separate backup server.

A look at Apple's new G5 Xserve and Xserve RAID

When the RAID set is initially created, the RAID box does a block-by-block integrity verification. During that period (which for my 1TB server took more than 15 hours), the default setting is to not make the volume available. Note: There is an option that allows the volume to be available immediately on set creation, even as the verification process is under way. But performance will be sluggish and part of the volume will be unavailable.

Once verification is complete, you can either restart and begin using the drive, or use disk utility to name it. This will not affect the RAID format, since it is below the level at which the disk utility works. The RAID box presents the drive to the Xserve as one unit and then decides how to distribute the data internally. It has its own processors and runs independently of the server. In fact, you can hook one server to each controller and share the Xserve RAID. Rebooting the Xserve will not affect the RAID unit (although the converse is not true).

A look at Apple's new G5 Xserve and Xserve RAID
RAID Event Log

Advanced features of the RAID admin program include slicing the array up into multiple volumes (which will destroy existing data), expanding the volume, rebuilding the parity info in the event of drive failure and restricting access to certain hosts.

A look at Apple's new G5 Xserve and Xserve RAID
Advanced features

I had an opportunity to test the new system a few days after the initial setup. One of my group shares here was oversubscribed, and it finally ran out of space. I needed to move data quickly and conscript a server into the Open Directory domain.

So I configured the Xserve to participate as a member of the domain and enabled both SMB and AFP services. On the Xserve, I opened workgroup manager and logged in locally. I could see the domain catalog! I created a new share and gave the user group rights. Still using Workgroup Manager, I redirected close to 50 user home directories.

Now came the speed test. I did a secure copy from one server to the RAID unit. The network interface to the Xerve is Gigabit Ethernet, and both units are on the same switch. Normally I get copy speeds of about 1GB per two minutes. In this case, the speed was better than twice that. I then removed the data from the first server and everything was up and running. Total time to move 10GB of data, plus configuration, was under 20 minutes! When this semester is over I plan to put the unit through a few video production tests and report back with my results.

I have only one negative comment, and this extends across the entire Xserve line. The problem is lights-out management. I use an American Power Conversion uninterrupted power supply (like most data centers) and have installed the powerchute network software on my Xserves. In the event of a power failure, the software will gracefully shut down the server. Unfortunately, that is where the management ends.

Unlike my Windows boxes, the servers will not reboot when the power returns. If I had simply killed the power, the server would register an ungraceful shutdown and boot back up when power was restored. But because it was shut down properly, it will not automatically reboot. In conversations with APC and Apple, I was told this is a known issue, though each one suggested the other should solve the problem. I don't care who solves it, but as a data center manager if I had to come in to the office at 3 a.m. to reboot 200 servers, I'd be less than happy. And for remote locations, this could mean the difference between buying the product or someone else's.

So take a note, Apple and APC: Get it fixed, and I'll be the first to congratulate everyone!

Having said that, the G5 Xserve is a solid improvement over the previous-generation G4-based model, and the RAID unit performs correspondingly well. The units are clearly enterprise quality, and given the low initial cost, and low power draw and heat output, data center managers everywhere should welcome them.

Did I miss something? Want to ask me something? Send your questions, comments and curses to Y.Kossovsky@ieee.org.

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Copyright © 2004 IDG Communications, Inc.

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