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Disk Support

The preponderance of SATA (Serial ATA) drives and their penetration into the server market means that most 1U servers are equipped with SATA by default. SCSI--the other choice--has strong supporters and strong detractors. However, the performance and reliability differences between SATA and SCSI aren't as many as you might believe. SATA drives are great for your system if your business data is on remote disks and you have many nondatabase applications. But for high-volume work, SCSI performs better. On the other hand, SCSI is more expensive. Don't pay for that technology unless you are certain you need the speed.

If you decide on SATA, you'll need RAID support. SATA works best in a RAID 5 environment. With SATA and RAID, you may no longer care about the SCSI-versus-the-world issue, but if you do, ask about support for SCSI also.

Expandability

There haven't been many changes in memory technology lately, at least not in mainstream servers. As a general rule, make sure there's at least one empty slot when you purchase the machine. This will give you some room to expand without having to completely replace existing chips.Memory expansion is necessary only if you plan to repurpose the box. If you intend to keep the box a full five years, match the number of memory slots and the type of memory those slots can hold to your projected use.

Servers now merge NICs into the motherboard. Find out how many NICs you need and what speeds they should support. If you purchase a machine with only 10/100 NICs built-in, you'll end up using one of the few slots for Gigabit Ethernet connectivity. And if you need Gigabit connectivity, make sure it is supported from the get-go.

If a new must-have technology comes out tomorrow, will you have room for it in your 1U? Consider iSCSI, which in some instances gives better performance with an accelerator than running over a NIC. Even without an iSCSI accelerator, you'll want two NICs: one to handle the data network and one for your iSCSI devices. That's one card slot used up in a machine that is likely to only have one to three slots to begin with.

Also consider the expansion bus. The expansion-card technologies it supports will have a large impact on potential uses. PCIX is the up-and-coming technology, but not all applications have moved to it. To that end, determine what the cards you're putting into the box require, and whether you have necessary support for PCI and PCI Enhanced.

How many drive bays will you need? If you aren't using SAN (storage area network) or NAS (network-attached storage) technology, you'll need to increase the drive capacity of the system as your data storage grows. Consider how much data the system is likely to generate in the first year, then multiply that by 2.5. That should give you a ballpark estimate of the minimum amount of growth in megabytes you'll need. Existing hard-drive space should be enough for the first year, and the total number of bays should ensure that you can expand your server to cover five years.

If you can't afford to take your server down to add hard-disk space, you need hot-swappable drives. Both SCSI and SATA support hot-swappable drives.The same is true for CPUs. Your application or OS may specify acceptable CPUs and minimum speeds, but the maximum number of CPUs and the maximum speed they run at will determine how much expandability you have. If the machine can only take two P4 CPUs, you're not likely to be using it in five years, but if it can handle 10 hyperthreaded CPUs, it may be a bit much for your needs even 10 years down the road. Decide what you need today and purchase a bit more than that. One word of warning: If you purchase a server with Hyperions in it, check with your software vendor to ensure it won't charge you for two CPUs for each single CPU in the box (some software vendors will).

In most scenarios, redundant power supplies are a necessity, not a luxury. It doesn't matter how well your UPS is configured or how many hours it will run, a single power supply in a server is a single point of failure. Purchase a machine that supports redundant power supplies.

Preinstalled OS

Once you determine the OS your application will run on, look to buy a machine that comes with the OS preinstalled. The days of having to hack Linux onto the box you need are in the past, and most Tier 1 vendors require that you have their special recovery partition on the machine, so make them work for it. Just make certain you're getting what you need for your particular application.

Does the vendor support offered meet your needs? A long-term warranty is great, but only if the vendor will guarantee to minimize your downtime by providing a quick turnaround. Every vendor ships the occasional problem machine, so ask the right questions. If you lose a hard drive, will the vendor repair it within 24 hours? Will you have to ship the server to the vendor? Will the vendor ask you to replace the hard disk?Buying a server is like buying a tuxedo: You don't want to buy a new one before it goes out of style. To that end, determine which features are key now, project five years out, and go up a size or two. It may seem baggy at first, but you'll be glad in the long run.

Don MacVittie is a technology editor at Network Computing. Previously, he worked at WPS Resources as an application engineer. Write to him at [email protected].

Before you buy a 1U server, determine what you need today and will need five years from now.

1) How many CPUs does the server support? How many are in it when ships?

2) How many memory slots are included and what speed are they?3) What technology does the PCI bus support and what is its speed?

4) How many drive bays are available?

For details and prices on specific systems, use our Interactive Buyer's Guide charts.