Exclusive: Sun's new big iron bends the rules
Sun Fire x4600 M2 octo-Opteron server proves a triumph of capability and designFollow @pvenezia
The LSI Logic controller embedded on the mainboard is limited to RAID 0/1 only, despite the presence of four hot-swap drive bays, and this controller shares a 100MHz bus with the two PCI-X slots. This all adds up to roughly 55MBps sequential reads and 42MBps sequential writes to local disk, as measured by Bonnie++ running on Red Hat Enterprise Linux 4 with a 4GB file size.
That’s about 80 percent of the performance of an older HP DL585 with one Ultra320 36GB SCSI drive. Enabling write caching would provide a boost, but the controller isn’t battery-backed, so that isn’t really an option for a production server.
Sun’s point of view is that nearly all applications for the x4600 will involve external disk in the form of direct-attached SCSI or a Fibre Channel or iSCSI SAN, and the local disk will be used only for booting and swapfile. Sun is absolutely correct, but like it or not, local disk should perform well enough to keep the server’s head above water.
This issue aside, the x4600 has a wide range of I/O options available directly from Sun, which is handy because the I/O slots are half-height. From 2Gbps and 4Gbps Fibre Channel HBAs from QLogic and Emulex to multiport Gigabit Ethernet and InfiniBand cards, there’s plenty to choose from. No 10Gbps card is available yet, but Sun plans to release one before the end of 2006. The use of half-height cards in the x4600 doesn’t seem to make sense at first, because there’s plenty of room in the case, but Sun stuck with half-height cards to remain consistent among the x4100, x4200, and x4600 servers.
Virtuoso of virtualization
The x4600’s plentiful processing and I/O resources make it a tremendous platform for virtualization, and sure enough, the server is on the VMware HCL (Hardware Compatibility List). I’ve been running VMware Infrastructure 3 on it for a week in the lab not only problem-free, but the server barely breaks a sweat while running eight two-processor Windows and Linux VMs under normal load.
It’s always hard to gauge actual VM host loads, because there’s so much fluctuation in the loads on the VMs themselves, but I would estimate that a maxed-out x4600 would handle 32 or more medium- to large-workload virtual servers with no complaints. For many shops, two of these servers would represent a datacenter’s worth of computing power -- and be fully redundant. This makes the power consumption not even worth mentioning.
The ILOM (Integrated Lights-Out Manager) card present in the x4600 conforms to Sun’s new Web UI standards, and it’s quick and easy to use. The Java-based remote console application is extremely responsive and among the best in the industry. I did most of the OS builds on this server via remote console sessions with little trouble, although some OSes won’t install properly from a remote-mounted ISO image. This is because the image mounts as a secondary CD-ROM device, not the primary, preventing some installers from locating the proper device.
Another note is that the onboard LSI Logic controller is not recognized by the Windows installer, requiring a driver disk in floppy format. As there is no floppy drive on the x4600, this floppy could be remotely mounted from a floppy image, or you could use a USB floppy drive; either way, it’s a bit of a pain. Once installed, however, Windows Server 2003 runs like a champ. Red Hat Enterprise Linux 4 Update 4 installed via Preboot Execution Environment with no problems.
Overall, the Sun Fire x4600 is a superb server with an obvious focus on virtualization, HPC, and database applications. If the local RAID controller supported RAID5, and the local disk I/O had more headroom, this server would be nearly perfect.