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Can My Desktop Make It in the Big Leagues?
bionic-john wonders: "I work in an environment where the dollar is more than almighty (who doesn't?). One of my cost savings plans is to use desktop computers as servers. They cost much less, the parts are readily available and/or interchangeable - as opposed to waiting for overnight proprietary or obscure parts from a vendor, and so on. I understand that servers have redundancy on disk and power - but this can be emulated for a fraction of the cost, as well. Is there a performance difference between a desktop and a server with the same specs? Chipsets are chipsets, motherboards are motherboard, and memory is memory -- is there something special about a server other than looking at the rack of blades and feeling special?"
- Disks fail. When you stick a server in a rack and leave it running for 5 or 6 years (unlike your average /.'ers desktop which probably gets a shake-up far more often), you won't regret being able to hot-swap a failed drive on your RAID array with a spare.
- Power supplies fail... To be honset, this isn't nearly as big a deal in the hot-swap arena as the hard drives. However, having 2 power supplies in a server machine means that things are significantly less bad when or if one of them happens to fail.
- Vendor commitment. From those old Compaq Proliants to the new Dell Poweredge machines, they were built to be stuffed in a rack and left untouched (unless something fails... see above). They'll come with hardware that those vendors usually stake their reputation on or even had a hand in building. Even the management software isn't always bad....
Bits of experience form my days of administrating a heterogenous network of desktops-as-servers in an ISV shop (disclaimer: I am professional software developer, I did administration because I was most knowledgeable OS geek). Several reasons why you don't want dektops to be servers: * Power supplies. Beleive me, PSUs DO fail. And more hosts you have the higher probability of failure you get. Even if you keep a stock of PSUs in the closet. It still takes you about 20 mins to get desktop/server up and running again, and night failure is far worse. * Rack mounting is not a vendor trick to charge you more money. If you have more than trivial infrastructure, wiring on desktops and "floor-tops" is going to be your favourite nightmare. * SCSI and SCSI raids are just a waste of money on a desktop but it is must have for intense, parallel access of many users to their homes, mailboxes, whatever on server. * not last and not least: having someone working on a server is probably most stupid idea in the whole IT. Whatever OS you use, beleive me, users will find a way to devour 98% CPU time and 99% of memory. That leaves for server applications.. well .. do the math :)
There are many other things, I just came up with whatever came into my mind right now.
my sstream of consciousness
What makes this guy a server? I'm no expert, but here's what I see:
- Lots of RAM. Came pre-configured with 1GB, and could handle many times that.
- There's only two 32-bit PCI slots, but four 64-bit slots. Handy if you want to add RAID or Fibre support, a nuisance if you want the more ordinary kind of add-in.
- No built-in sound card.
- No AGP interface. Instead, there's a basic 4MB video interface on the motherboard.
- Massive fans.
Anyway, bionic-john is correct in thinking that a workstation will do as a server, provided only that you don't demand more of it than it's designed to do. (Which is always a question anyway.) I work for a hosting/colocation provider, and I see all kinds of stuff pressed into service as servers: cheap white boxes, Sun and Apple workstations, even an X-Box or two. Ultimately, all computers are interchangable. Specialized computers are just a matter of convenience and cost-effectiveness.Buy quality parts, and everything should be OK. Don't expect a $300 emachine to last out the year.
A few tips:That said, dual CPUs and rackmount cases are a luxury, and if cost is that important, you can skip them. And make sure there is a process in place to check on the health of the server. Even waving your hand behind the box once a week to check how hot the PSU exhaust is can save the business a lot of headache. (Hint: if no air is blowing, replace the PSU, and check the HDDs to make sure they're both still working.)
Also, be wary of Dell. They use non-standard power supplies, so if your PSU goes out, you can't hop down to the local computer store and buy a replacement.
RAID 0 is striping. RAID 1 is mirroring.
RAID-1, you mean; RAID-0 is striping (hence 0 redundancy). And yes, anything even vaguely important should be on a RAID array in addition to backups. RAID doesn't help much when your controller freaks out or you hit a fs or user error.
Unless you're willing to trade off warranty, latency and quality against sequential transfer rate and storage, this means go SCSI.
Buy decent fans (twin ball bearing or so?) and monitor them. If noise isn't a concern, this might be a good application for Delta's more extreme fans
On a 1U rackmount, your case fans will most likely be your CPU fans too. Pair of Opterons? Fit passive heatsinks and a bunch of 15kRPM case fans, should be sorted.
Do they make those in 64GB versions now? No? I'll just use another RAID array then, thanks.
Depends what your files are and how you're accessing them; do you want to have to hit disk for every access? With a lot of clients (which is kind of the point with a file server), a lot of memory is practically a requirement.
A good kernel should avoid this, and HTT can help, but when you can get a well kitted-out 1U dual 1.4GHz PIII for under £500, why not?
My local computer store doesn't sell 1U PSU's. Dell do however support redundant ones; I'll take that over downtime while I replace a single one, however cheap/available.