Re: [ANNOUNCE] Btrfs: a copy on write, snapshotting FS

[Chris Mason <chris.mason@oracle.com>]

On Sat, Jun 16, 2007 at 12:03:06AM +0200, Florian D. wrote:
> Chris Mason wrote:
> > Well, apparently I get get the silly stuff wrong an infinite number of
> > times.  Sorry, lets try again:
> > 
> > diff -r 38b36aaaa731 disk-io.c
> > --- a/disk-io.c	Fri Jun 15 13:50:20 2007 -0400
> > +++ b/disk-io.c	Fri Jun 15 16:52:38 2007 -0400
> > @@ -541,6 +541,8 @@ int write_ctree_super(struct btrfs_trans
> >  	else
> >  		ret = submit_bh(WRITE, bh);
> >  	if (ret == -EOPNOTSUPP) {
> > +		get_bh(bh);
> > +		lock_buffer(bh);
> >  		set_buffer_uptodate(bh);
> >  		root->fs_info->do_barriers = 0;
> >  		ret = submit_bh(WRITE, bh);
> > 
> 
> ha! it is working now. some numbers from here(with the fio-tool):

Great, I'll have a v0.3 out on Monday with that fix rolled in.

> 
> 1. sequential read
> 2. random writes
> 3. sequential read again
> 
> filesize:300MB, bs:4K
> 
>    btrfs                  reiserfs               ext3
>    usr% sys% bw   sec.    usr% sys% bw   sec.    usr% sys% bw   sec.
> 1  5    51   68.3 4.6     1    17   67.4 4.6     5    24   68.0 4.6
> 2  0    1    0.7  431     2    21   29.8 10.5    3    18   29.0 10.8
> 3  0    1    2.3  133     1    19   70.5 4.4     5    24   68.6 4.5
> 
> bw: MB/sec.
> ext3: -o data=writeback,barrier=1
> 
> 20GB LVM2 partition on a RAID6 (4 SATA-disks)

Strange, these numbers are not quite what I was expecting ;)  Could you
please post your fio job files?  Also, how much ram does the machine
have?  Only writing doesn't seem like enough to fill the ram.

-chris