On Thu, 20 Jan 2011, Brian Chrisman wrote: > I've performed some simple testing of sparse files on ceph. Summary, > ceph reports full file size to 'du' and 'ls', where it should return > actual storage usage to 'du'. Creating a sparse file on ceph does not > actually use the full file size in storage (which is correct > behavior). Is this a known issue, or should I submit a bug? This is a design choice. The MDS doesn't know how many blocks are allocated because, with the exception of reporting st_blocks to du, it doesn't need to. This makes metadata smaller and the protocols simpler. sage > > dd if=/dev/urandom of=random.data bs=1024 count=1024 > dd if=random.data of=sparse_file.data > dd if=random.data of=sparse_file.data bs=1024k seek=1024 > ls -l sparse_file.data > du -sh sparse_file.data > > A reference output: ext3 > [root@test11 tmp]# ls -l sparse_file.data > -rw-r-r- 1 root root 1074790400 Jan 19 18:43 sparse_file.data > [root@test11 tmp]# > [root@test11 tmp]# du -sh sparse_file.data > 2.1M sparse_file.data > [root@test11 tmp]# > > Output from: ceph > [root@test11 fs0]# ls -l sparse_file.data > -rw-r-r- 1 root root 1074790400 Jan 19 18:45 sparse_file.data > [root@test11 fs0]# du -sh sparse_file.data > 1.1Gsparse_file.data > [root@test11 fs0]# > > However, df shows that 1GB of space is not actually used in the filesytem: > > [root@test11 fs0]# df -h > Filesystem Size Used Avail Use% Mounted on > ... > 10.200.98.111:/ 11T 30M 11T 1% /fs0 > [root@test11 fs0]# > > -Brian > -- > To unsubscribe from this list: send the line "unsubscribe ceph-devel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
