Why does btrfs benchmark so badly in this case?

2013-08-08 Thread John Williams
Phoronix periodically runs benchmarks on filesystems, and one thing I have noticed is that btrfs always does terribly on their fio "Intel IOMeter fileserver access pattern" benchmark: http://www.phoronix.com/scan.php?page=article&item=linux_310_10fs&num=2 Here, btrfs is more than 6 times slower t

Re: Why does btrfs benchmark so badly in this case?

2013-08-08 Thread Josef Bacik
On Thu, Aug 08, 2013 at 09:13:04AM -0700, John Williams wrote: > Phoronix periodically runs benchmarks on filesystems, and one thing I > have noticed is that btrfs always does terribly on their fio "Intel > IOMeter fileserver access pattern" benchmark: > > http://www.phoronix.com/scan.php?page=art

Re: Why does btrfs benchmark so badly in this case?

2013-08-08 Thread Clemens Eisserer
> What is going on here? Why is btrfs doing so poorly? Funny thing, I was thinking exactly the same when reading the article ;) Regards -- 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://vg

Re: Why does btrfs benchmark so badly in this case?

2013-08-08 Thread Josef Bacik
On Thu, Aug 08, 2013 at 09:13:04AM -0700, John Williams wrote: > Phoronix periodically runs benchmarks on filesystems, and one thing I > have noticed is that btrfs always does terribly on their fio "Intel > IOMeter fileserver access pattern" benchmark: > > http://www.phoronix.com/scan.php?page=art

Re: Why does btrfs benchmark so badly in this case?

2013-08-08 Thread John Williams
On Thu, Aug 8, 2013 at 12:40 PM, Josef Bacik wrote: > On Thu, Aug 08, 2013 at 09:13:04AM -0700, John Williams wrote: >> Phoronix periodically runs benchmarks on filesystems, and one thing I >> have noticed is that btrfs always does terribly on their fio "Intel >> IOMeter fileserver access pattern"

Re: Why does btrfs benchmark so badly in this case?

2013-08-08 Thread Josef Bacik
On Thu, Aug 08, 2013 at 01:23:22PM -0700, John Williams wrote: > On Thu, Aug 8, 2013 at 12:40 PM, Josef Bacik wrote: > > On Thu, Aug 08, 2013 at 09:13:04AM -0700, John Williams wrote: > >> Phoronix periodically runs benchmarks on filesystems, and one thing I > >> have noticed is that btrfs always

Re: Why does btrfs benchmark so badly in this case?

2013-08-08 Thread Chris Murphy
On Aug 8, 2013, at 2:23 PM, John Williams wrote: > > So I guess the reason that ZFS does well with that workload is that > ZFS is using smaller blocks, maybe just 512B ? Likely. It uses a variable block size. > I wonder how common these type of non-4K aligned workloads are. > Apparently, peop

Re: Why does btrfs benchmark so badly in this case?

2013-08-08 Thread Zach Brown
> I also don't know if any common use fs has an optimization whereby > just the modified sector(s) is overwritten, rather than all sectors > making up the file system block being modified. Most of them do. The generic direct io path allows sector sized dio. The very first bit of do_blockdev_direc

Re: Why does btrfs benchmark so badly in this case?

2013-08-09 Thread Kai Krakow
Josef Bacik schrieb: >> So I guess the reason that ZFS does well with that workload is that >> ZFS is using smaller blocks, maybe just 512B ? > > Yeah I'm not sure what ZFS does, but if you are writing over a block and > the size/offset isn't aligned then you'd see similar issues with ZFS since

Re: Why does btrfs benchmark so badly in this case?

2013-08-12 Thread Josef Bacik
On Fri, Aug 09, 2013 at 11:35:33PM +0200, Kai Krakow wrote: > Josef Bacik schrieb: > > >> So I guess the reason that ZFS does well with that workload is that > >> ZFS is using smaller blocks, maybe just 512B ? > > > > Yeah I'm not sure what ZFS does, but if you are writing over a block and > > t