On Wed, Sep 20, 2017 at 3:06 PM, Timofey Titovets <nefelim...@gmail.com> wrote: > 2017-09-20 11:59 GMT+03:00 shally verma <shallyvermacav...@gmail.com>: >> On Wed, Sep 20, 2017 at 2:25 PM, Timofey Titovets <nefelim...@gmail.com> >> wrote: >>> 2017-09-20 11:44 GMT+03:00 shally verma <shallyvermacav...@gmail.com>: >>>> One more catch... I am initiating fio from non-btrfs filesystem i.e. >>>> pwd is ext4 based fs where as mount point is btrfs. >>>> Could that make difference? >>>> >>>>> Thanks >>>>> Shally >>> >>> Only matter are where you store test file =) >>> If you store test file on btrfs, pwd does nothing. >>> >> >> Then steps listed in previous mail should work right? Am listing them >> again here: >> >> " ---- >>> >>> 1. mount -t btrfs -o compress-force=zlib /dev/sdb1 mnt >>> >>> 2. fio --directory=mnt/ --numjobs=1 --direct=0 --buffered=1 --bs=64k >>> --rw=write --iodepth=128 --name=test --size=1G >>> --buffer_compress_percentage=100 --buffer_pattern=0xFF --refill_buffer >>> --ioengine=libaio >>> >>> 1GN file written uncompressed. Here no compression invoked (though >>> compress-force=zlib) >>> >>> 3. cp mnt/test ./ --> copy back fio generated test file from btrfs >>> mount point to local drive >>> >>> 4. hex dump test file (all FFs) -- confirmed that data is compressible >>> no random data. >>> >>> 5. cp test mnt/ --> now, copy same test again back to mount point >>> (reverse of step 3) . Now, here I see during copying compression is >>> invoked. >>> >>> I am using kernel 4.9 and compress-foce is said to be working for >>> kernel > 2.13 from wiki ... so I wonder what's so special with cp >>> command which is not happening during fio writes??? >> >> "----- >> >> Thanks >> Shally >> >> >>> -- >>> Have a nice day, >>> Timofey. > > I did try reproduce your problem on 4.14, i'm hard to explain that > happens and why file created by FIO will not use compression. > > Suggest workaround: > rm -v /mnt/test.0.0 > dd if=/dev/zero of=/mnt/test.0.0 bs=1M count=1024
You mean "compression" using "dd" write. > fio --directory=$HOME/test/ --numjobs=1 --direct=1 --buffered=0 > --bs=64k --rw=write --iodepth=128 --name=test --size=1G > --buffer_compress_percentage=100 --buffer_pattern=0xFF --refill_buffer > --ioengine=libaio You mean "no compression" during fio writes and you see similar behavior as I? BTW here --direct=0 and --buffered = 1. > > You can check if data compressed by filefrag -v /mnt/test.0.0 (you > will see encoded extents) > if I do filefrag on mnt/test.0.0, then it shows up like this: ext: logical_offset: physical_offset: length: expected: flags: 0: 0.. 1: 1329922.. 1329923: 2: 1: 2.. 3: 1329923.. 1329924: 2: 1329924: 2: 4.. 5: 1329924.. 1329925: 2: 1329925: An new to this, how does it says extents are encoded here? Thanks Shally > -- > Have a nice day, > Timofey. -- 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
