[linux-elitists] GNU/Linux box as a RAID device?

Rob McGee list+Elite@nodns4.us
Wed Oct 26 13:28:29 PDT 2005


On Wednesday 2005-October-26 14:10, Joakim Ziegler wrote:
> So, he asked me something the other day, which made me think. He
> wanted to know if he could set up a Linux box with a bunch of (SATA
> or SATA-II) disks in RAID, and then hook his mac up to that box via
> SCSI or Fiber Channel, and have the RAID device show up as a SCSI
> device on the Mac end.
>
> Thinking about it, it seems like it should be possible. So, is there
> any way to stuff a Fiber Channel or SCSI card in a Linux box and
> export a device so it looks like a SCSI device to another machine?

A long time ago (before I knew much of anything about computers) I had 
SCSI. This was in the pre-EIDE days, where you had to have SCSI to get 
anything approaching 1GB in capacity.

Quite by accident I discovered that you can in fact chain SCSI busses 
across multiple computers. Link the adapters with an external cable, 
and just follow the SCSI rules ... termination on both ends of the bus, 
every device (the host adapters are included) with a unique SCSI ID. 
And of course be careful, it is rather fragile, since anything 
happening to either machine at the wrong time could mess up your data.

I don't know about SATA or FC. This was ancient SCSI-II, when the 
majestic 80486 ruled the Earth. Since then I've gone with cheaper 
storage. SCSI does not fit my idea of "cheap". (Worth it in some 
circumstances, of course.)


On a tangent, I am about to buy SATA RAID for home, so I'll throw this 
out for comments. I'm considering either the 3ware 8506 or 9500S 4-port 
models with 4 250 or 300GB drives. I'm tired of ATA drive failures. 
Seagate seems to have increased their warranties lately so I'll be 
going with them rather than Maxtor or WDC "disposable" drives. I know 
how HDD manufacturers can be a sore spot ... some will swear by one, 
others will swear at them.

Is 100mbit enough for regular use? I mean, we're not doing video 
streaming or editing, just normal office and light graphics work. 
Where's the bottleneck here, the physical disk access or the network?

I know both of those controllers are overkill for our needs, but I'm 
figuring needs evolve too. The price differential is only about US$30, 
so on that basis I'm leaning toward the 9500S. But if something a lot 
cheaper (about US$300 for the 9500S) will be almost as good, I'd 
appreciate a pointer.
-- 
    Rob - /dev/rob0



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