On 2010-Sep-24 00:58:47 +0800, "R.G. Keen" <k...@geofex.com> wrote: >That may not be the best of all possible things to do >on a number of levels. But for me, the likelihood of >making a setup or operating mistake in a virtual machine >setup server is far outweighs the hardware cost to put >another physical machine on the ground.
The downsides are generally that it'll be slower and less power- efficient that a current generation server and the I/O interfaces will be also be last generation (so you are more likely to be stuck with parallel SCSI and PCI or PCIx rather than SAS/SATA and PCIe). And when something fails (fan, PSU, ...), it's more likely to be customised in some way that makes it more difficult/expensive to repair/replace. >In fact, the issue goes further. Processor chipsets from both >Intel and AMD used to support ECC on an ad-hoc basis. It may >have been there, but may or may not have been supported >by the motherboard. Intels recent chipsets emphatically do >not support ECC. Not quite. When Intel moved the memory controllers from the northbridge into the CPU, they made a conscious decision to separate server and desktop CPUs and chipsets. The desktop CPUs do not support ECC whereas the server ones do - this way they can continue to charge a premium for "server-grade" parts and prevent the server manufacturers from using lower-margin desktop parts. This means that if you want an Intel-based solution, you need to look at a Xeon CPU. That said, the low-end Xeons aren't outrageously expensive and you generally wind up with support for registered RAM and registered ECC RAM is often easier to find than unregistered ECC RAM. > AMDs do, in general. AMD chose to leave ECC support in almost all their higher-end memory controllers, rather than use it as a market differentiator. AFAIK, all non-mobile Athlon, Phenom and Opteron CPUs support ECC, whereas the lower-end Sempron, Neo, Turion and Geode CPUs don't. Note that Athlon and Phenom CPUs normally need unbuffered RAM whereas Opteron CPUs normally want buffered/registered RAM. > However, the motherboard >must still support the ECC reporting in hardware and BIOS for >ECC to actually work, and you have to buy the ECC memory. In the case of AMD motherboards, it's really just laziness on the manufacturer's part to not bother routing the additional tracks. >The newer the intel motherboard, the less likely and more >expensive ECC is. Older intel motherboards sometimes >did support ECC, as a side note. On older Intel motherboards, it was a chipset issue rather than a CPU issue (and even if the chipset supported ECC, the motherboard manufacturer might have decided to not bother running the ECC tracks). >There's about sixteen more pages of typing to cover the issue >even modestly correctly. The bottom line is this: for >current-generation hardware, buy an AMD AM3 socket CPU, >ASUS motherboard, and ECC memory. DDR2 and DDR3 ECC >memory is only moderately more expensive than non-ECC. Asus appears to have made a conscious decision to support ECC on all AMD motherboards whereas other vendors support it sporadically and determining whether a particular motherboard supports ECC can be quite difficult since it's never one of the options in their motherboard selection tools. And when picking the RAM, make sure it's compatible with your motherboard - motherboards are virtually never compatible with both unbuffered and buffered RAM. >hardware going into wearout. I also bought new, high quality >power supplies for $40-$60 per machine because the power >supply is a single point of failure, and wears out - that's a >fact that many people ignore until the machine doesn't come >up one day. "Doesn't come up one day" is at least a clear failure. With a cheap (or under-dimensioned) PSU, things are more likely to go out of tolerance under heavy load so you wind up with unrepeatable strange glitches. >Think about what happens if you find a silent bit corruption in >a file system that includes encrypted files. Or compressed files. -- Peter Jeremy
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