Guys, I think you're both absolutely right about the complexity of simultaneous access to shared disks - something has to control that, and it's NOT the disk array. At my customer site, I was using HP's high-availability cluster software MC/ServiceGuard, and the operating system's logical volume manager controls the shared access (you prepare the volume group as shared, then mount it in 'exclusive' mode where it keeps track somehow how's mounting it - so that no simultaneous access is possible - MC/SG is for high-availability only, not for parallel performance like Oracle RAC).
Let's take a step back. Let's assume I don't want too much smarts, and that I will look after the mounting so that no two SAN nodes will attempt to mount the same volume / partition. That should make it easier, right? You mentioned something about reversing the IEEE1394 stack - can you be a bit more precise?
E.g. the home built disk array is partitioned into two slices ("1" and "2"). Computer A mounts slice 1, computer B mounts slice 2.
BTW: The disk array I used has a great feature - you associate LUNs (space allocated on the disk array) to the World Wide Name of the FC HBA (like a MAC address in FibreChannel land). It's called "LUN Security"... Do Firewire controllers have an Identification of themselves?
I appreciate everyone's comments about SAN and NAS, and apologize for not having made my point clearer.
I'm not interested in NAS / Fileserver / anything running over Ethernet, simply coz it's a no-brainer to set them up. The whole post to ask-slashdot was probably more theoretical than anything else, to discuss what started as a crazy idea with fellow geeks.
I know I can get a Firewire-IDE enclosure, but the question is, what happens if it hangs off a Firewire hub together with two computers? Will both be able to see it? How do you partition it (just normal fdisk I assume)? What if the two computers have different OS's? Then of course you've got to make sure that no two computers mount the same partition...
Then I started taking it further: The device used at the customer site was a real disk array with RAID5DP and lots of cache. Would it be possible to build a low-cost disk array e.g. using linux - very much similar to the SanCUBE. Then you could do much more than with just a FireWire-IDE disk; think of "LUN security" - ensure that computer X only sees the partitions that it's supposed to see...
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Guys, I think you're both absolutely right about the complexity of simultaneous access to shared disks - something has to control that, and it's NOT the disk array. At my customer site, I was using HP's high-availability cluster software MC/ServiceGuard, and the operating system's logical volume manager controls the shared access (you prepare the volume group as shared, then mount it in 'exclusive' mode where it keeps track somehow how's mounting it - so that no simultaneous access is possible - MC/SG is for high-availability only, not for parallel performance like Oracle RAC).
Let's take a step back. Let's assume I don't want too much smarts, and that I will look after the mounting so that no two SAN nodes will attempt to mount the same volume / partition. That should make it easier, right? You mentioned something about reversing the IEEE1394 stack - can you be a bit more precise?
E.g. the home built disk array is partitioned into two slices ("1" and "2"). Computer A mounts slice 1, computer B mounts slice 2.
BTW: The disk array I used has a great feature - you associate LUNs (space allocated on the disk array) to the World Wide Name of the FC HBA (like a MAC address in FibreChannel land). It's called "LUN Security"... Do Firewire controllers have an Identification of themselves?
That's it - that's exactly what I am after!!!! Let me know if you get any further!!
I appreciate everyone's comments about SAN and NAS, and apologize for not having made my point clearer.
I'm not interested in NAS / Fileserver / anything running over Ethernet, simply coz it's a no-brainer to set them up. The whole post to ask-slashdot was probably more theoretical than anything else, to discuss what started as a crazy idea with fellow geeks.
I know I can get a Firewire-IDE enclosure, but the question is, what happens if it hangs off a Firewire hub together with two computers? Will both be able to see it? How do you partition it (just normal fdisk I assume)? What if the two computers have different OS's? Then of course you've got to make sure that no two computers mount the same partition...
Then I started taking it further: The device used at the customer site was a real disk array with RAID5DP and lots of cache. Would it be possible to build a low-cost disk array e.g. using linux - very much similar to the SanCUBE. Then you could do much more than with just a FireWire-IDE disk; think of "LUN security" - ensure that computer X only sees the partitions that it's supposed to see...
Again, thanks for all the comments!