[geeks] SCSI cabling question

[Andrew Weiss]

The 3 Channel is a Ultra Wide NetRaid HP adapter with 4MB of cache

The 1 Channel is an Ultra 2 LVD Megaraid 466 Series with 32MB of cache

The problem is that the Big PC with the 1" Hot swap bays has 12 of them each
with separate connectors, and I couldn't afford 18GB 1" ers after buying the
18GB 5 pack of 1.6" ers... luckily the 1.6" ers will fit in the Gateway
NS-8000 once I make some sleds... this machine actually has a real backplane
so all I need is a 2 connector cable

The 18's are Ultra wide I think (Barracudas), and the 9's are Ultra 2 LVD
Compaq 10K's.

I have 6 9's and 5 18's.  I wanted to put the 6 9's in a RAID 5
configuration, but my enclosures only hold 4 in a row.  Looks like I'm
capped out at 27GB of capacity (4x9) unless I use the 3 channel controller,
but I'm unsure if you can bind an array across channels... if so it'd be
simple.  I'd put the lower performing 3-channel in and go with it.  Perhaps
buy some more cache later... Performance isn't a huge issue... 40MB/s is
fine for me.  It's the capacity that I want.

Andrew

----- Original Message -----
From: "Dan Sikorski" <me at dansikorski.com>
To: "The Geeks List" <geeks at sunhelp.org>
Sent: Thursday, January 23, 2003 9:54 PM
Subject: Re: [geeks] SCSI cabling question


> I'd bet on that not working.
>
> you mentioned the cache size and number of channels on each of the two
> of your controllers, but you didn't mention the speed.  ultra-wide?
> ultra2?  My guess is that you'd benefit a lot more from spreading the
> drives out over two or more channels than you would from the additional
> cache, so unless the 3channel is fast/wide and the 1 channel is ultra2
> or something, i'd stick to the 3 channel card.
>
> -Dan Sikorski
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