Christoph Anton Mitterer posted on Wed, 30 Dec 2015 20:28:00 +0100 as excerpted: > On Wed, 2015-12-30 at 18:26 +0000, Duncan wrote: >> That should work. Cat the files to /dev/null and check dmesg. For >> single mode it should check the only copy. For raid1/10 or dup, >> running two checks, ensuring one is even-PID while the other is >> odd-PID, should work to check both copies, since the read-scheduler >> assigns copy based on even/odd PID. Errors will show up in dmesg, as >> well as cat's STDERR. > That doesn't seem very reliable to me, to be honest... plus it wouldn't > work in any RAID56 or dupN (with n!=2) case, when that gets sooner or > later implemented. Well, yes, but right now except on raid56... and there's a good chance it'll work for a year at least, as I've seen no first-patches yet to implement n-way (which I'm sure looking forward to), after which perhaps he'll have implemented the multi-btrfs on partitions or lvm thing that I actually prefer, myself. Meanwhile, it's a pretty clever solution, I think. =:^) > Also, I'd kinda guess (or better said: hope) that the kernel's cache > would destroy these efforts, at least when the two reads happen mostly > in parallel. I was thinking run them in parallel, but you're right, you'd have to run them serially and dumpcache between runs. -- Duncan - List replies preferred. No HTML msgs. "Every nonfree program has a lord, a master -- and if you use the program, he is your master." Richard Stallman -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
