The graph uploaded shows 'Up speed' and 'Down speed', I just assumed that this is network speed and not disk I/O. Is this correct assumption? If so, how does the traffic to/from the /dev/sdX look like (e.g. iostat or ksysguard) ? W.r.t. USB: I had quite some trouble with NEC/Renesas USB3 host controller 2 years back. I got it working once under windows7 after quite some drivers version trials. Under linux it is listed, but I don't use is anymore; On the same PC under windows7 it doesn't work anymore. For btrfs on WD elements and Sandisk Extreme on ASUS H87M-Pro with kernels 3.x kernels (64-bit) I got similar freezes/perfomance issues as mentioned here. The same fs configurations and tests on sata cabled (2TB HDD) did not show these hickups. I have now mostly ext4 on those USB connected disk, so with 4.3-rcX kernels I cant tell more. There might be many configuration issues if a drive is connected via removable USB, like writeback-caching etc. I have not looked into all possible issues any further. A month ago I got quite some random I/O and timeout errors on a 4TB raw dd_rescue copy action (1 HDD in USB3 bay), kernel 4.1.6. Then hooked-up all 3 disks, including rootfs, to another motherboard via sata and not a single error. On the other hand, I have also a 2TB disk connected via USB2 formatted btrfs and online 24/7 for over a year and it works fine. So I would (temporary) connect this WB 6TB via sata and use some latest 64-bit liveCD/DVD linux distro and see how the disktraffic is for some file copy or defrag action. And then, step by step go back to your original configuration. Also make sure the disk is not filled much more than 95%, as that could easily lead to the situation that your latest active files will easily be very scattered, so not beneficial for fs performance. -- 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
