On Wed, Sep 20, 2017 at 2:25 PM, Timofey Titovets <nefelim4ag@xxxxxxxxx> wrote: > 2017-09-20 11:44 GMT+03:00 shally verma <shallyvermacavium@xxxxxxxxx>: >> 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. -- 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
