How to create a terabyte storage array?

[Zach]

For what it's worth, with more than four drives, even if they're on
their own IDE channel, you're going to start running up against the
throughput limitation of the PCI bus, which I believe is around 133
MB/s (that's bytes not bits), which has to be shared with other
devices including the network adapter.  Modern 7200 rpm IDE drives can
be expected to deliver around 40-50 MB/s each.  There is some overhead
inherent to raid so it won't be a perfect multiple of each drive's
performance, but you can see how PCI could quickly become the
performance bottleneck.

It may be that with 5 drives, 4 if you don't count the parity, you may
be taking advantage of all or most of what the PCI bus has to offer
even if you have two drives per channel.

On 12/2/05, Ed Fletcher <ed at fletcher.ca> wrote:
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> Soo-Hyun Choi wrote:
> | Thanks all to discuss this matter.
> |
> | One more navie question though is that how (or where) do I get a cable
> | to connect all 5 HDDs? Normally, an IDE cable comes with dual HDDs
> | connection, not multiple, isn't it?
> |
>
> You can't have more than two IDE hard drives on a single cable.  And you
> should really only have one drive per cable as it will help the array
> respond faster.
>
> You need something like a Promise IDE card:
>
> http://pcworld.pricegrabber.com/search_techspecs.php/masterid=419815
>
> Each one has two IDE ports to allow it to control four drives.  But, as
> I said, you are better off having one drive per port/cable.  Two cards
> will let you have four drives in the array.
>
> I just googled the promise card.  There are lots of others.  I just
> happen to have promise cards in my server.
>
> HTH,
> Ed
> - --
> Ed Fletcher
> ed at fletcher.ca
>
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