On Mon, Jul 24, 2017 at 8:22 PM, Marat Khalili <mkh@xxxxxx> wrote: >>> This may be a stupid question , but are your pool of butter (or BTRFS pool) >>> by any chance hooked up via USB? If this is USB2.0 at 480mitb/s then it is >>> about 57MB/s / 4 drives = roughly 14.25 or about 11MB/s if you shave off >>> some overhead. >> >>Nope, USB 3. Typically on scrubs I get 110MB/s that winds down to >>60MB/s as it progresses to the slow parts of the disk. > > It could have degraded to USB2 due to bad connection/loose electrical contacts. You know USB3 needs extra wires, and if it lost some it'd connect (or reconnect) in USB2 mode. I'd check historical kernel messages just in case, and/or unmount and reconnect to be sure. Actually I'm wrong, the device I was testing for this thread is SATA. What confused me is the thread is about raid1 and my Btrfs raid1 is USB 3. But anyway all devices scrub at 100+MB/s but balance is much slower than even 1/2. -- Chris Murphy -- 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
