I tried the same routine on 32GB usb sticks. Same exact problems. 32GB seems a bit much for a --mixed btrfs. I haven't tried ssd_spread, maybe it's beneficial. However, as I wrote above, disabling autodefrag gets rid completely of the "INFO: hung task" messages but even though the kernel doesn't complain about blocked kworkers, the rsync process still blocks for several minutes throughout the whole copy.
On Wed, Sep 3, 2014 at 4:44 AM, Chris Murphy <li...@colorremedies.com> wrote: > > On Sep 2, 2014, at 12:40 AM, Duncan <1i5t5.dun...@cox.net> wrote: >> >> Mkfs.btrfs used to default to 4 KiB node/leaf sizes; now days it defaults >> to 16 KiB as that's far better for most usage. I wonder if USB sticks >> are an exception... > > USB sticks > 1 GB get 16KB nodesize also. At <= 1 GB, mixed-bg is default as > is 4KB nodesize. Probably because queue/rotational is 1 for USB sticks, they > mount without ssd or ssd_spread which may be unfortunate (I haven't > benchmarked it but I suspect ssd_spread would work well for USB sticks). > > It was suggested a while ago that maybe mixed-bg should apply to larger > volumes, maybe up to 8GB or 16GB? > > > Chris Murphy > > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
