If you’re careful, perhaps. “Real” servers have”enterprise” features, such as dedicated hardware RAID controllers. Workstations and consumer motherboards don’t.
1. Real servers have beefy construction, like big power supplies. One of the workstations (Dell Precision 390) I tried to use had lots of empty drive bays. I plugged in three extra SATA drives, so it had four drives total. It worked fine for long enough to load an operating system. I was in the middle of patching when I heard a *POP* and smelled smoke. Turns out that the stock power supply can’t support that many drives (even though the case has the bays, the power supply has the connectors, and the specs say that is a supported configuration).
2. Workstation BIOS settings may stop you from loading certain software. XenServer requires CPU’s that support hardware virtualization to run Windows virtual machines, and this is usually a setting in BIOS that’s off by default. Another workstation I tried (HP xw4600) has newer CPU’s that support virtualization but its “dumbed down” BIOS doesn’t allow you to see or set this. So even though it was a new quad core with 8GB of RAM, I couldn’t load XenServer on it. Boo.
3. Workstation “RAID” controllers aren’t the same as enterprise RAID controllers. The “RAID controllers” that come integrated on consumer motherboards aren’t really controllers. Linux refuses to participate in the lie. If you google “fakeRAID” you’ll get lots of explanations like this one from Ubuntu:
In the last few years, a number of hardware products have come onto the market claiming to be IDE or SATA RAID controllers. These have shown up in a number of desktop/workstation motherboards. Virtually none of these are true hardware RAID controllers. Instead, they are simply multi-channel disk controllers combined with special BIOS configuration options and software drivers to assist the OS in performing RAID operations. This gives the appearance of a hardware RAID, because the RAID configuration is done using a BIOS setup screen, and the operating system can be booted from the RAID.
Real RAID controllers have their own CPU, cache RAM, and maybe a battery to protect the RAM. They are usually expensive. The dedicated RAID CPU offloads RAID related computations from the system CPU. FakeRAID chipsets don’t have CPU’s and the system CPU does everything, including RAID operations. You can easily tell when you try to use one of these with Linux. Linux doesn’t see the “RAID”. At all. Linux just sees the drives as plain old drives, regardless of how you attempt to configure the fakeRAID controller otherwise.
4. Newer workstations have newer chipsets that may be poorly supported in certain operating systems. Some operating systems like Red Hat Enterprise Linux or Openfiler are considered “stable”, which is code-speak for “works great on older well known hardware, but not on this new-fangled unproven stuff”. For example, the latest Openfiler 3.2 won’t run on my HP xw4600. I get errors like:
Kernel panic - not syncing: DMAR hardware is malfunctioning
This is apparently a bug in Red Hat as well. I fiddled and farted around with passing Openfiler various kernel parameters, etc., but I gave up after a couple of hours of fiddling with it. The bottom line is that if you are unlucky enough to be trying to use some particular hardware that your Linux of choice doesn’t like, you are screwed. Enterprise server vendors sell their servers preloaded with most common Linux distros, so you can be pretty sure that they will run Linux just fine.
So having said all of that, if you are lucky, and you happen to pick workstations or motherboards that have the features you need, you can make them work. For example, I found that my Dell Precision 390’s serve well as XenServer physical hosts for virtual machines. The are 3 GHz quad core machines, take up to 8GB of RAM, and you can get to the BIOS setting to turn hardware virtualization on.
If you are buying used equipment to run Linux, google and make sure that you find numerous positive reports from other users!