On Tue, 16 Feb 2016, Scott McGillivray wrote: > Hello > > I am using Ubuntu 15.10 with latest nightly 4.5 kernel. Ubuntu creates > 16 RAM drives as /dev/ram0 - ram16 by default and i am trying to test > bcache and use one of these as a cache device. > > wipefs /dev/sdd > wipefs /dev/sdd -a > wipefs /dev/ram0 > wipefs /dev/ram0 -a > make-bcache -B /dev/sdd -C /dev/ram0 Does it work with /dev/zram0? You would prep it something like this: modprobe zram echo $((1024*1024*1024)) > /sys/block/zram0/disksize # 1GB make-bcache -C /dev/zram0 -Eric > At this point there were no errors output but there is also no UUID > entry in /sys/fs/bcache/. Only register and register_quiet. > > bache-super-show correctly prints info about both block and cache > devices when queried but when i try to manually attach the cache > device with echo cset.uuid > /sys/block/bcache0/bcache/attach i get no > error but in dmesg i see > > bcache: __cached_dev_store() Can't attach > 3f2521a6-2103-4e2e-a47d-cc56558e8f7d: cache set not found > > If i repeat this example but use another sd block device as cache then > it works OK. > > Can anyone confirm if it should be possible to use the ramdisk based > block device as a caching device with bcache ? > > I also tried to use a loop device as cache and that didn't work > either.. i got "kernel bug" in dmesg for > drivers/md/bcache/super.c:1812. RIP [] > cache_alloc.isra.21+0x646/0x670[bcache] > > Does bcache need the cache device to be a certain block type i.e sd 8 > ? Should i be able to use any block device from /proc/devices as a > cache device ? > > The kernel options used for ramdisk are: > > CONFIG_BLK_DEV_RAM=y > CONFIG_BLK_DEV_RAM_COUNT=16 > CONFIG_BLK_DEV_RAM_SIZE=65536 > CONFIG_BLK_DEV_RAM_DAX=y > > Thank you. > Scott > -- > To unsubscribe from this list: send the line "unsubscribe linux-bcache" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- Eric Wheeler, President eWheeler, Inc. dba Global Linux Security 888-LINUX26 (888-546-8926) Fax: 503-716-3878 PO Box 25107 www.GlobalLinuxSecurity.pro Linux since 1996! Portland, OR 97298 -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
