On Mon, Sep 05, 2011 at 03:51:17PM +0200, Swâmi Petaramesh 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.
That's because dpkg is known for using (f)sync very heavily. btrfs honours the sync request in all cases, so it's much much slower than ext3, which doesn't. There's an LD_PRELOAD library called "eatmydata" that you can use to paper over the issue by running it as a wrapper around dpkg. Hugo. -- === Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk === PGP key: 515C238D from wwwkeys.eu.pgp.net or http://www.carfax.org.uk --- Always be sincere, whether you mean it or not. ---
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