Basic IDE - disk per channel performance

Blake Barnett shadoi at nanovoid.com
Mon Nov 13 17:55:22 MST 2006


On Nov 13, 2006, at 4:27 PM, Michael Halcrow wrote:

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> On Mon, Nov 13, 2006 at 05:15:38PM -0700, Andrew Jorgensen wrote:
>> On 11/13/06, Kenneth Burgener <kenneth at mail1.ttak.org> wrote:
>>> Is there a benefit of putting a software raid array on separate
>>> channels?
>>
>>> From The Linux Software-RAID HOWTO:
>>
>> It is very important, that you only use one IDE disk per IDE bus.
>
> That's why I have three chipsets to service 6 disks in my RAID. Don't
> put the OS disk and a RAID disk on the same channel. And don't try to
> use two SIL0680 chips in the same box (the Linux driver probably can't
> handle two cards); get a SIL0680 and a High Point or a Promise. Or,
> better yet, get a 4-channel IDE card.
>
> Keep in mind that trying to manage 6+ ribbon cables in any box can be
> a pain in the neck. The IDE connections seem to be a bit flimsy in my
> box too, leading to phantom drive failures (OS-reported failures that
> aren't really drive failures; some cable just needed to be
> reseated). The next time I build a software RAID, I am definitely
> going all SATA.

In my experience (albeit focused purely on server hardware) there are  
so many downsides to doing IDE RAID that it doesn't even make sense  
to use it.  I suppose if you're trying to find the absolute cheapest  
solution then it's viable, but then you'd be forced to ask yourself;  
"How much do I value this data?" and "Why not just use software RAID  
and/or rsync-type backups?".  Chances are, unless it's something  
you've purchased you don't really require RAID at all, and if you do,  
then the cost of a really good SATA controller (w/battery backup!!)  
shouldn't be an issue.  I prefer the 3ware (AMCC now) 95xx series of  
cards.

-Blake




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