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From: Sergei Trofimovich <slyich@gmail.com>
To: "Swâmi Petaramesh" <swami@petaramesh.org>
Cc: linux-btrfs <linux-btrfs@vger.kernel.org>
Subject: Re: Rename BTRfs to MuchSlowerFS ?
Date: Mon, 5 Sep 2011 22:25:23 +0300	[thread overview]
Message-ID: <20110905222523.4531abe0@sf.home> (raw)
In-Reply-To: <4E64D3D5.7020407@petaramesh.org>

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On Mon, 05 Sep 2011 15:51:17 +0200
Swâmi Petaramesh <swami@petaramesh.org> wrote:

> Hi list,
> 
> I don't trust theoretical benchmarks that much and prefer "real-life 
> benchs" on the occasion, so here's mine:
> 
> Given 4 laptops, the most powerful of which was running BTRFS and the 
> others ext3 or ext4, all machines running Ubuntu 11.04 Natty 32-bit with 
> a stock Ubuntu 2.6.38-11 kernel, all machines were given the following 
> FS-intensive task :
> 
> - Upgrade O.S. from Ubuntu 11.04 Natty to 11.10 Oneiric (beta), using a 
> local packages apt-cacher.
> 
> Machines :
> 
> 1/ Acer Aspire 3104 WLMi, AMD Sempron Mobile 3500+ @1.8 GHz, 1.5 GB RAM, 
> 80 GB SATA HD, ext4 over standard partitions
> 
> 2/ Asus EeePC 1005PE, Intel Atom N450 @1.66 GHz, 2 GB RAM, 250 GB SATA 
> HD, ext3 over AES-128 encrypted LVM
> 
> 3/ Compaq Mini CQ10-740SF, Intel Atom N455 @1.66 GHz, 1 GB RAM, 250 GB 
> SATA HD, ext4 over standard partitions
> 
> 4/ Dell XPS M1330, Intel Core 2 Duo T9300 @2.5 GHz, 2 GB RAM, 160 B SATA 
> HD, BTRFS over AES-128 encrypted LVM
> 
> Results :
> 
> All 3 ext3 /  ext4 machines took between 60 and 90 minutes to complete 
> their upgrade.
> 
> BTRFS machine took 20 HOURS so far, still counting (ETA 15 minutes left).
> 
> Wow. Impressive.

I've seen similar problem on Ubuntu-11 + Aspire One (8GB of slow "SSD").
More specifically half of ubuntu install went very fast and when
disk was ~50% free things _suddenly_ gone slow.

According to strace fsync() started to take ~10 seconds(!) and upper.
It's not common filesystem behaviour, but a plain (and hard to catch?) bug.

I don't have the box anymore. The root cause it to be found by some
brave soul yet.

I wonder if latencytop would get the profile of the issue.

Maybe, btrfs degrades only after certain (insanely large?) amount of fsync()
calls?

-- 

  Sergei

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  parent reply	other threads:[~2011-09-05 19:25 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-05 13:51 Rename BTRfs to MuchSlowerFS ? Swâmi Petaramesh
2011-09-05 14:00 ` Hugo Mills
2011-09-05 14:20   ` Roman Mamedov
2011-09-05 17:10     ` Elric Milon
2011-09-05 14:17 ` David McBride
2011-09-05 19:25 ` Sergei Trofimovich [this message]
2011-09-06 15:30   ` Swâmi Petaramesh
2011-09-06 17:11     ` Fajar A. Nugraha
2011-09-07 14:15       ` Swâmi Petaramesh
2011-09-15 19:37         ` Felix Blanke
2011-09-15 22:16           ` Fajar A. Nugraha
2011-09-16  6:21             ` Maciej Marcin Piechotka
2011-09-16  6:42               ` Fajar A. Nugraha
2011-09-16  8:39                 ` Maciej Marcin Piechotka
  -- strict thread matches above, loose matches on Subject: below --
2011-09-05 16:23 Tomasz Chmielewski
2011-09-05 16:25 ` Christoph Hellwig
2011-09-05 16:29   ` Hugo Mills
2011-09-08  7:04     ` youagree

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