[Gllug] A SATA Raid card worth having?

[Ben Fitzgerald]

On Fri, Jan 27, 2006 at 12:38:38AM +0000, Russell Howe wrote:
> On Thu, Jan 26, 2006 at 11:46:59PM +0000, Ben Fitzgerald wrote:
> > see what you are saying. on modern 64-bit pci:
> > 
> > "Later versions of PCI enable true 64-bit data transfers using up to a
> > 133MHz clock to enable transfer speeds of up to 1066 Mbytes/sec.)" [1]
> > 
> > ata drives reach 133mb/s max transfer but scsi goes much higher so I
> > guess this could be a bottleneck if you had a scsi controller with
> > several fast units hanging off it.
> 
> I'd be astounded to see a drive that could do 133MB/s sustained!
> 
> I suspect most 7200rpm drives max out at about 40, perhaps 50MB/s? 15k
> RPM should be faster, but I don't know how much faster...

so would I, but when calculating the max transfer rate surely you should
use the burst rate as the top value, even though that may only last a
very short time.

<snip>
> Sure, but is the system BIOS smart enough to not just sit there and say
> "Hard disk failure" or "Bootloader not found" because it's too
> distracted by a failed drive?
> 
> Probably very BIOS-dependent, and needs thorough testing before
> deployment.

wouldn't disagree with that.

> I think this is the kind of thing you get with hardware RAID - all these
> things have been (or should have been!) thought about by the people who
> built it. There should be no I/O bottlenecks, the CPU in it should be
> fast enough to do what's needed, and for RAID boxes, things like
> cooling, hotswappable parts, modular design with replaceable fan modules
> for when fans die and other things like that can all make a difference.
> To develop something this polished by yourself, using software RAID as a
> base, is quite a challenge, and, I suspect, the hardware RAID may come
> out cheaper overall. It will also come with things like a warranty and a
> support telephone number :)

yes, linux excluded you often get what you pay for in life!

<snip>
> Still, it seems that we've covered most of the pros and cons :)

yes, thanks for your thoughts.

ben.

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