> I'm not 100% sure, but a quick look at the code suggests that > 16TB is the upper limit for normal read/write operations on > a block device like /dev/md0 on a 32bit host. This is because it uses > the page cache, and that uses 4K pages with a 32bit index, hence > 16TB. Uh-oh! I hope this doesn't apply to a 64 bit host running 2.6.26-2-amd64, or is it a limitation of md? In fairly short order (a year, maybe), I'm going to need to go beyond 16T employing RAID6 on some number more than eight 3T drives. I know a lot can happen in a year, but when it comes to upgrading code, sometimes a lot doesn't happen, either. > A filesystem using a 16TB device would not be limited in the same way > as it caches individual files, not the whole device (individual files > would still be limited to 16TB). > I think if you access the block device with O_DIRECT you might be > able to bypass the 16TB barrier. Try hacking the program > to add O_DIRECT to the open mode. I'm running XFS, but perhaps I could get the developers to put in a switch for this, if need be. -- 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
