Current best recommendation for Athlon 64 motherboard?

[Bryan J. Smith]

Ken Snider wrote:
> Some other considerations.
> A drive blowing on a hardware RAID rarely locks up the RAID controller 
> - the same can not be said of most onboard ATA controllers,

Yes, and that issue with hotplug includes "FRAID" cards.
FRAID cards often lack hotplug, despite marketing.
In a nutshell, you need some *intelligence* between the rest of the 
system and the drive controllers.
That intelligence then handles hotplug.

> and some SCSI controllers as well.

Unlike ATA, SCSI *always* comes with intelligence, so its more of an 
issue with bus disconnect.

But regardless of whether ATA or SCSI drive controllers are used, if 
there is an intelligence on the card, then the rest of the system 
doesn't see the hardware, and hotplug becomes easy.

This is not like FRAID which still allows the system to have direct 
access to the drives, using the FRAID driver to "hide" them.

> RAID controllers that have battery-backed-up NVRAM can complete writes much
> more reliably in failure scenarios - and ensure that even in a 
> power-loss situation, or OS lockup, data will get flushed to disk, 
> though this may or may not matter to you given your usage and 
> filesystem.

Battery-backed RAM is only necessary for DRAM, not SRAM.
Hence why 3Ware Escalade 9000 series have batteries (because they use 
DRAM as well as SRAM) whereas earlier Escalades do not (SRAM-only).
Of course, you should *never* cut the power to the system for more than 
a few seconds, otherwise the SRAM loses their states.
But SRAM doesn't need to be refreshed like DRAM, so only a tiny amount 
of power needs to be applied (which is easily done).

> lastly, many RAID controllers offer far more ports than you could hope 
> to get on a mainboard - the 3ware 8 and 12 drive controllers actually 
> have 8 or 12 on-board channels, I've never seen a motherboard with 
> more than 5
> channels (you wouldn't want to use master/slave configurations on 
> these controllers, in fact you don't even have that option with the 
> 3ware cards).

Actually, the nVidia Pro 2200+2050 has 8 SATA ports.
And the new AHCI firmware allows up to 32 ports to be intelligently 
controlled in software (including using queuing on the drive).
But even AHCI is still not intelligence, and that means 2-12x the data 
load on your interconnects.
It's not the XORs that kill, but passing all the data through the CPU 
  over its interconnects and back.

> I have software RAID deployed on over 50 boxes here, but on the ones I 
> *really* care about, I use, at minimum, hardware mirroring, to offload 
> the
> rebuild process in the case of a bad disk, as well as to reduce the risk
> that a bad disk may hose the underlying IDE driver.

Commodity drives are not designed for 24x7 operation, but only 8 hours x 
50,000 restarts.
Hitachi and many manufacturers rate their drives at 14x5 maximum weekly 
usage.
Again, that is for *commodity* drives.
Enterprise drives are rated differently.

The interface has nothing to do with drive quality, although typically 
most ATA models are commodity design/tested.
But some SCSI drives do come off the same lines as ATA/SATA.
And a few, select ATA/SATA drives come of enterprise SCSI lines too.

--
Bryan J. Smith   mailto:b.j.smith at ieee.org
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