[Sunhelp] Fault tolerant system.

[Gregory Leblanc]

Disclaimer:  I don't have enough money to actually purchase a system like
this, but I've gone over it and diagramed it a couple of times, "just in
case".

> -----Original Message-----
> From: Fletcher, Joe [mailto:joe.fletcher at Metapack.com]
> 
> I'm looking for some hints of putting together the following 
> hardware rig.
> 2x E420Rs, each with two dual SCSI adapters added and two 
> A1000 disk arrays.
> The system will be running RSF-1 "cluster" software. We will 
> have Veritas VM
> installed
> as well.  Initially I'd like confirmation of just how the 
> whole lot should
> be cabled together.
> This really needs a few diagrams to help explain the options but I'm
> assuming some people
> aren't usiing MIME enabled emailers. Lets call the servers S1 
> and S2. The
> arrays can be Ar1 and Ar2.
> Each array has two SCSI connectors, ports 1 and 2. Assume we 
> will be working
> with controllers in slot4 
> on each server. Each controller has ports A and B. Still with 
> me so far? 

Yeah, pretty straight forward.  

> What I think we need to do is connect 	S1 portA to Ar1 
> port1 and portB to
> Ar2 port2
> 					S2 portB to Ar1 port2 
> and portA to
> Ar2 port1

Sounds good to me.

> We then use RAID manager to carve up the disks within the 
> arrays (12 disks
> in each)
> and manage the resulting virtual disks through Veritas at 
> operating system
> level.
> 
> 	S1	S2		
> 	 |    \    / |
> 	 |      \/	 | 
> 	 |    /   \	 |
> 	Ar1	Ar2

Yeah, that's how I'd do cabling, as you're aiming for redundancy, so that if
any 1 piece fails, you still have the other to pick up.  

> Alternatives are to chain the two arrays together and single port each
> server thus:
> 
> S1----Ar1----Ar2 ----S2

I wouldn't go this way, as it's likely to hamper performance (the servers
don't have a bus dedicated to each array), and it takes a bit away from the
fault tolerance as well.  Later,
	Greg