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Re: [mythtv-users] AM2+ motherboard with support for ECC RAM for media player / server

Bob wrote:
Roger Heflin wrote:
Bob wrote:
Bill Williamson wrote:
On Wed, May 7, 2008 at 4:23 PM, Bob <spam@homeurl.co.uk <mailto:spam@homeurl.co.uk>> wrote:

    Bob wrote:
    > Unbuffered / Registered obviously.

    Bad form Bla Bla Bla but just to update the list, the abit A-S78H also
    supports Un-buffered ECC RAM, it doesn't have FireWire though

Why do you think that ECC vs non ECC ram will have any bearing on stability of a media computer ? If you're going ECC, why would you not also go SCSI?

I don't disagree with wanting stability, but the reality is that ECC likely will not give you any.
ECC RAM corrects bit errors in memory which could cause a crash or other problems, these errors while rare are estimated to occur once a month per GB of RAM, I'm planing have 2 or 4 GBs and I'll leave the system up all the time, which is why reliability and low power consumption are a must.
Actually the errors don't happen that often anymore, not sure exactly why, but I have monitored huge amounts of ram (10000+ GB for months) and the errors happen pretty rarely except on machines getting huge numbers of errors, in a given month with a machine with 32GB on it very few of the machines get any errors at all, the few that get errors don't usually get only 1 error.

That's interesting to have some real world figures, thank you.
But, if you are monitoring ECC then this will give you a chance to know about the memory *BEFORE* it causes you machine to be unstable and crash randomly without you knowing why it is crashing. It would also speed up correcting the issue as you don't have to guess what the actual issue is.

What do you use to monitor the errors?

On AMD boards a program called mcelog (you will have to put it in cron) will work-most soft MCE errors are ECC errors either in the CPU or in memory, also something in the kernel (may require an extra module in some distribtions) called edac will also work. The edac thing will also work on *SELECT* intel boards, mostly on the intel side only the higher end (dual socket server boards) are supported, on AMD because the ECC is in the CPU itself it is pretty much supported everywhere if the MB will take ECC ram.

It is really one of the advantages of the AMD cpus, as you can easily get ECC in them without buying a single socket server grade MB for a lot more money that you have to get with the Intel cpus.

This is exactly the reason I'm after an AM2+ MotherBoard that supports it, I like these 2 boards [4] but I've had bad experiences with both abit [0] and asus [1] in the past in both cases not actually their fault but once bitten.. the only downside is the lack of FireWire which as Ron on debian-users points out that can be fixed with a PCI card, the only problem with that is these mATX are quite short on space and I'll probably put a DVB-C card in.

In the order of the vendors, Supermicro's quality is on average better than any of the other MB only vendors.

I don't want to build a "proper" server with ECC Registered RAM and SCSI because it'll cost a fair bit more for a fairly marginal improvement in stability and longevity.
SCSI does not matter anymore, in the last 3 years the SATA/IDE disk have got a lot better, I think the issue is that the disk manufacturers figured out better platter quality control. I have experience with large samples of SCSI (2003-800 scsi disks) and SATA disks (2000+ IDE/SATA disks), and they both have similar failures rates, if you go back to large numbers of IDE/SCSI disks in the 2000-2004 range this was not the case and the SATA disks were utter crap were you could expect 10-20% failures in the first 6 months, and the SCSI/FC disks had very low failure rates.

[0] abit BP6 motherboard dual skt 370 celeron board, that took ECC RAM, great home SMP board with a clear upgrade path, only intel moved some stuff around on the P!!! and shafted them / us

[1] some ASUS Slot A board with a crappy VIA chipset, [2] I won't touch VIA again [3] and shouldn't really hold it against ASUS but I sort of have

I have a via chipset, and I have used other VIA MB's, and I would probably avoid VIA if possible, but if they are the only ones with the required features I would use them.


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