Paul> I am currently trying to build a RAID5 array across 12 Paul> disks. The problem is there is a bug in the linux firewire Paul> drivers that is causes problems when multiple disks are accessed Paul> randomly at the same time. With that number of disks, and that transport, why aren't you looking at using RAID6 as well? The rebuild time on RAID5 leaves a window where a second failure could really mess you up. Paul> As you can imagine the soft RAID5 drivers try to do exactly Paul> that - access all 12 disks at once. Can the software raid Paul> drivers be made to only access one disk at a time and to wait Paul> for a requested to be fulfilled before submitting another? Kiss your system performance down the drain. But you might be able to make this work. Have you tried: 1. the serialize_io=1 option to the SBP driver? 2. moving to USB2 instead? I've never gotten my firewire enclosure to work with Linux. Prolific Chipset. 3. Maybe tweak /sys/block/sd*/queue/nr_requests to be 1 for each device, so that you don't queue up too many commands to each disk. That way you can still run commands across all 12 disks, but only one per disk. 4. Do you have multiple firewire controllers as well? That will help performance. Good luck, and let us know how it works out. Oh yeah, more details on your kernel version, MD setup, etc would be helpful as well. John - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
