Hi Stan, It looks like those docs are out of date. Echoing the names of the cache and backing devices to 'register' is sufficient. 'attach' is for adding a new backing device to an existing cache set after the fact.
Slava On Fri, Oct 3, 2014 at 2:37 PM, Stan Hoeppner <[email protected]> wrote: > Probably so. I'm working from: > https://www.kernel.org/doc/Documentation/bcache.txt > > Do I need to manually register the backing devices? I formatted the LUNs and > the SSD on the same command line. Instructions above say you don't need to > register manually if doing it that way. Also, I'm not using the udev rules, > but doing everything manually at this point. And there is a reason for that. > I don't have complete control/access to the development system. The rootfs > is NFS mounted read only, and changes such as udev rules take days... > > > Thanks, > Stan > > > On 10/03/2014 04:21 PM, Slava Pestov wrote: >> Hi Stan, >> >> The 'register' command attaches the backing device, you don't need to >> do the separate 'attach' step. Perhaps the instructions you are >> following are out of date. >> >> Slava >> >> On Fri, Oct 3, 2014 at 2:14 PM, Stan Hoeppner <[email protected]> wrote: >>> I assumed it did not go fine due to the immediate error on the echo >>> command. FYI, this is my first attempt at bcache. >>> >>> bash: echo: write error: Invalid argument >>> >>> How can I confirm both dm-4 and dm-7 (bcache0 and bcache1) are both >>> attached and that bcache is running? >>> >>> FYI, this is my first attempt at bcache, so I'm following the instructions >>> precisely. Also, dm-4 and dm-7 are 44 TB RAID6 LUNs. If my testing shows >>> substantial benefit in decreasing RMW we will be looking at deploying >>> bcache with one or more mirrored pairs of SSDs to 14 of these arrays. >>> That's per system. And we'll be deploying 100s of such systems. >>> >>> I emailed Kent's gmail address about this about a month ago and never >>> received a response. At some point, probably next year some time, the >>> company I'm working for may want to contract with him for a short time >>> before moving into production with this. >>> >>> Thanks, >>> Stan >>> >>> >>> >>> On 10/03/2014 03:57 PM, Slava Pestov wrote: >>>> It looks like everything went fine, what is the problem? >>>> >>>> On Fri, Oct 3, 2014 at 1:50 PM, Stan Hoeppner <[email protected]> >>>> wrote: >>>>> >>>>> On 10/03/2014 03:37 PM, Slava Pestov wrote: >>>>>> Please include any bcache messages printed in dmesg when this happens. >>>>> >>>>> [87579.418945] bcache: bch_cached_dev_attach() Can't attach dm-4: already >>>>> attached >>>>> [87579.418947] bcache: __cached_dev_store() Can't attach >>>>> 8246b830-95d4-420d-aff8-894efc348801 >>>>> [87579.418947] : cache set not found >>>>> >>>>> For completeness, these are the steps are performed, soup to nuts: >>>>> >>>>> # wipefs -a /dev/dm-4 >>>>> 4 bytes [58 46 53 42] erased at offset 0x0 (xfs) >>>>> # wipefs -a /dev/dm-7 >>>>> 4 bytes [58 46 53 42] erased at offset 0x0 (xfs) >>>>> # wipefs -a /dev/sdc >>>>> # ./make-bcache -B /dev/dm-4 /dev/dm-7 -C /dev/sdc >>>>> Already a bcache device on /dev/sdc, overwrite with --wipe-bcache >>>>> # ./make-bcache -B /dev/dm-4 /dev/dm-7 -C /dev/sdc --wipe-bcache >>>>> UUID: 501486ea-d614-4a32-a137-bc8e004fcb85 >>>>> Set UUID: 8246b830-95d4-420d-aff8-894efc348801 >>>>> version: 0 >>>>> nbuckets: 761856 >>>>> block_size: 1 >>>>> bucket_size: 1024 >>>>> nr_in_set: 1 >>>>> nr_this_dev: 0 >>>>> first_bucket: 1 >>>>> UUID: 261cf532-ca93-45b7-a8fb-1eff57078953 >>>>> Set UUID: 8246b830-95d4-420d-aff8-894efc348801 >>>>> version: 1 >>>>> block_size: 1 >>>>> data_offset: 16 >>>>> UUID: eeca31ab-a632-4d7b-94f6-35e9b878344f >>>>> Set UUID: 8246b830-95d4-420d-aff8-894efc348801 >>>>> version: 1 >>>>> block_size: 1 >>>>> data_offset: 16 >>>>> # echo /dev/dm-4 > /sys/fs/bcache/register >>>>> # echo /dev/dm-7 > /sys/fs/bcache/register >>>>> # echo /dev/sdc > /sys/fs/bcache/register >>>>> >>>>> # ls -la /dev/b* >>>>> brw-rw---- 1 root disk 253, 0 Oct 3 14:39 /dev/bcache0 >>>>> brw-rw---- 1 root disk 253, 1 Oct 3 14:39 /dev/bcache1 >>>>> >>>>> # mkfs.xfs /dev/bcache0 >>>>> meta-data=/dev/bcache0 isize=256 agcount=44, >>>>> agsize=268435455 blks >>>>> = sectsz=512 attr=2, projid32bit=0 >>>>> data = bsize=4096 blocks=11709285374, >>>>> imaxpct=5 >>>>> = sunit=0 swidth=0 blks >>>>> naming =version 2 bsize=4096 ascii-ci=0 >>>>> log =internal log bsize=4096 blocks=521728, version=2 >>>>> = sectsz=512 sunit=0 blks, lazy-count=1 >>>>> realtime =none extsz=4096 blocks=0, rtextents=0 >>>>> >>>>> # mkfs.xfs /dev/bcache1 >>>>> meta-data=/dev/bcache1 isize=256 agcount=44, >>>>> agsize=268435455 blks >>>>> = sectsz=512 attr=2, projid32bit=0 >>>>> data = bsize=4096 blocks=11709285374, >>>>> imaxpct=5 >>>>> = sunit=0 swidth=0 blks >>>>> naming =version 2 bsize=4096 ascii-ci=0 >>>>> log =internal log bsize=4096 blocks=521728, version=2 >>>>> = sectsz=512 sunit=0 blks, lazy-count=1 >>>>> realtime =none extsz=4096 blocks=0, rtextents=0 >>>>> >>>>> # mount -o inode64,nobarrier,noatime,nodiratime /dev/bcache0 /mnt/V1A >>>>> # mount -o inode64,nobarrier,noatime,nodiratime /dev/bcache1 /mnt/V2A >>>>> >>>>> # ls -la /sys/fs/bcache >>>>> total 0 >>>>> drwxr-xr-x 3 root root 0 Oct 3 14:39 . >>>>> drwxr-xr-x 6 root root 0 Oct 2 16:32 .. >>>>> drwxr-xr-x 7 root root 0 Oct 3 14:50 >>>>> 8246b830-95d4-420d-aff8-894efc348801 >>>>> --w------- 1 root root 4096 Oct 3 14:39 register >>>>> --w------- 1 root root 4096 Oct 3 14:50 register_quiet >>>>> >>>>> # echo 8246b830-95d4-420d-aff8-894efc348801 > >>>>> /sys/block/bcache0/bcache/attach >>>>> bash: echo: write error: Invalid argument >>>>> >>>>> >>>>>> On Fri, Oct 3, 2014 at 1:21 PM, Stan Hoeppner <[email protected]> >>>>>> wrote: >>>>>>> # ls -la /sys/fs/bcache >>>>>>> total 0 >>>>>>> drwxr-xr-x 3 root root 0 Oct 3 14:39 . >>>>>>> drwxr-xr-x 6 root root 0 Oct 2 16:32 .. >>>>>>> drwxr-xr-x 7 root root 0 Oct 3 14:50 >>>>>>> 8246b830-95d4-420d-aff8-894efc348801 >>>>>>> --w------- 1 root root 4096 Oct 3 14:39 register >>>>>>> --w------- 1 root root 4096 Oct 3 14:50 register_quiet >>>>>>> >>>>>>> >>>>>>> # echo 8246b830-95d4-420d-aff8-894efc348801 > >>>>>>> /sys/block/bcache0/bcache/attach >>>>>>> bash: echo: write error: Invalid argument >>>>>>> >>>>>>> >>>>>>> What's the problem here? >>>>>>> >>>>>>> Thanks, >>>>>>> Stan >>>>>>> -- >>>>>>> To unsubscribe from this list: send the line "unsubscribe linux-bcache" >>>>>>> in >>>>>>> the body of a message to [email protected] >>>>>>> More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
