Re: ext4 vs btrfs performance on SSD array

2014-09-05 Thread Christoph Hellwig
On Wed, Sep 03, 2014 at 10:01:58AM +1000, NeilBrown wrote: Do we still need maximums at all? I don't think we do. At least on any system I work with I have to increase them to get good performance without any adverse effect on throttling. So can we just remove the limit on max_sectors and the

Re: ext4 vs btrfs performance on SSD array

2014-09-05 Thread Jeff Moyer
Christoph Hellwig h...@infradead.org writes: On Wed, Sep 03, 2014 at 10:01:58AM +1000, NeilBrown wrote: Do we still need maximums at all? I don't think we do. At least on any system I work with I have to increase them to get good performance without any adverse effect on throttling. So

Re: ext4 vs btrfs performance on SSD array

2014-09-05 Thread Jens Axboe
On 09/05/2014 10:40 AM, Jeff Moyer wrote: Christoph Hellwig h...@infradead.org writes: On Wed, Sep 03, 2014 at 10:01:58AM +1000, NeilBrown wrote: Do we still need maximums at all? I don't think we do. At least on any system I work with I have to increase them to get good performance

Re: ext4 vs btrfs performance on SSD array

2014-09-02 Thread Theodore Ts'o
- the very small max readahead size For things like the readahead size, that's probably something that we should autotune, based the time it takes to read N sectors. i.e., start N relatively small, such as 128k, and then bump it up based on how long it takes to do a sequential read of N

Re: ext4 vs btrfs performance on SSD array

2014-09-02 Thread Zack Coffey
While I'm sure some of those settings were selected with good reason, maybe there can be a few options (2 or 3) that have some basic intelligence at creation to pick a more sane option. Some checks to see if an option or two might be better suited for the fs. Like the RAID5 stripe size. Leave the

Re: ext4 vs btrfs performance on SSD array

2014-09-02 Thread Austin S Hemmelgarn
I wholeheartedly agree. Of course, getting something other than CFQ as the default I/O scheduler is going to be a difficult task. Enough people upstream are convinced that we all NEED I/O priorities, when most of what I see people doing with them is bandwidth provisioning, which can be done much

Re: ext4 vs btrfs performance on SSD array

2014-09-02 Thread Jan Kara
On Tue 02-09-14 07:31:04, Ted Tso wrote: - the very small max readahead size For things like the readahead size, that's probably something that we should autotune, based the time it takes to read N sectors. i.e., start N relatively small, such as 128k, and then bump it up based on how

Re: ext4 vs btrfs performance on SSD array

2014-09-02 Thread Theodore Ts'o
On Tue, Sep 02, 2014 at 04:20:24PM +0200, Jan Kara wrote: On Tue 02-09-14 07:31:04, Ted Tso wrote: - the very small max readahead size For things like the readahead size, that's probably something that we should autotune, based the time it takes to read N sectors. i.e., start N

Re: ext4 vs btrfs performance on SSD array

2014-09-02 Thread NeilBrown
On Mon, 1 Sep 2014 18:22:22 -0700 Christoph Hellwig h...@infradead.org wrote: On Tue, Sep 02, 2014 at 10:08:22AM +1000, Dave Chinner wrote: Pretty obvious difference: avgrq-sz. btrfs is doing 512k IOs, ext4 and XFS are doing is doing 128k IOs because that's the default block device

Re: ext4 vs btrfs performance on SSD array

2014-09-01 Thread Dave Chinner
On Tue, Aug 26, 2014 at 07:39:08PM -0400, Nikolai Grigoriev wrote: Hi, This is not exactly a problem - I am trying to understand why BTRFS demonstrates significantly higher throughput in my environment. I am observing something that I cannot explain. I am trying to come up with a good

Re: ext4 vs btrfs performance on SSD array

2014-09-01 Thread Christoph Hellwig
On Tue, Sep 02, 2014 at 10:08:22AM +1000, Dave Chinner wrote: Pretty obvious difference: avgrq-sz. btrfs is doing 512k IOs, ext4 and XFS are doing is doing 128k IOs because that's the default block device readahead size. 'blockdev --setra 1024 /dev/sdd' before mounting the filesystem will

Re: ext4 vs btrfs performance on SSD array

2014-08-27 Thread Duncan
Nikolai Grigoriev posted on Tue, 26 Aug 2014 19:39:08 -0400 as excerpted: Kernel: 3.8.13-35.3.5.el6uek.x86_64 #2 SMP Fri Aug 8 21:58:11 PDT 2014 x86_64 x86_64 x86_64 GNU/Linux Btrfs v0.20-rc1 I've no answer for your question, but you know how old both your kernel and btrfs-progs versions

Re: ext4 vs btrfs performance on SSD array

2014-08-27 Thread Nikolai Grigoriev
Duncan 1i5t5.duncan at cox.net writes: Nikolai Grigoriev posted on Tue, 26 Aug 2014 19:39:08 -0400 as excerpted: Kernel: 3.8.13-35.3.5.el6uek.x86_64 #2 SMP Fri Aug 8 21:58:11 PDT 2014 x86_64 x86_64 x86_64 GNU/Linux Btrfs v0.20-rc1 I've no answer for your question, but you know how

ext4 vs btrfs performance on SSD array

2014-08-26 Thread Nikolai Grigoriev
Hi, This is not exactly a problem - I am trying to understand why BTRFS demonstrates significantly higher throughput in my environment. I am observing something that I cannot explain. I am trying to come up with a good filesystem configuration using HP P420i controller and SSDs (Intel S3500).