Everything except the 4KB blocksize I would say. While ZFS and Btrfs are very different on-disk, they are both Copy-On-Write filesystems with extents, compression and cheap snapshots. I don't know how the 4KB blocksize settings translates onto Btrfs.
They are both really suited for the append-only workload CouchDB presents. Wout. On Sep 18, 2010, at 9:49 , Metin Akat wrote: > What part of this blog post is relevant to btrfs? > > On Fri, Sep 17, 2010 at 10:22 PM, Chris Anderson <[email protected]> wrote: >> On Thu, Sep 16, 2010 at 6:22 PM, Tyler Gillies <[email protected]> wrote: >>> Wow, thanks for the thought out writeup! >>> >> >> here's a blog post http://letsgetdugg.com/2010/06/25/couchdb-on-zfs/ >> >>> On Thu, Sep 16, 2010 at 12:47 PM, Randall Leeds >>> <[email protected]>wrote: >>> >>>> Disclaimer: I'm no file systems expert. >>>> >>>> I recommend something with extents otherwise you might take a big >>>> performance hit while couch deletes old db files after compaction. >>>> Compression sounds cool as long as you can do it really fast (are >>>> there setups where this happens in hardware?). >>>> >>>> reiserfs: >>>> According to wikipedia it "still uses the big kernel lock (BKL) — a >>>> global kernel-wide lock" which makes performance on multiple cores >>>> suffer. >>>> It's big benefit, as I always understood it, is being able to pack >>>> smile files together into single blocks. You will likely not have lots >>>> of small files with Couch :-P >>>> >>>> xfs: >>>> Delayed allocation might be a big performance win with a Couch. Since >>>> outstanding writes are committed together in chunks and then fsync'd >>>> all together I bet this feature would do good things for Couch >>>> performance. >>>> >>>> ext(3|4) >>>> I'd recommend ext4 over ext3. Delayed allocation like xfs as well as >>>> the multiblock allocator should make it much better than ext3. You >>>> also get extents. >>>> >>>> btrfs/zfs: >>>> Some of the features of each sound interesting, but nothing that >>>> stands out to me as "great for CouchDB". Snapshots and backups are >>>> cool, but Couch is doing this for you already in a sense due to the >>>> way the btree is appended: CouchDB documents are, in a sense, >>>> copy-on-write. Checksumming is cool if you think it's important for >>>> your data integrity. If you want snapshots for backup you can always >>>> use CouchDB replication. >>>> >>>> If you run any tests I'd be very, very interested in seeing your results. >>>> >>>> -Randall >>>> >>>> On Thu, Sep 16, 2010 at 03:11, Metin Akat <[email protected]> wrote: >>>>> I'm sure almost everybody out there is using ext4/3 (including me), >>>>> but what about filesystems like btrfs, zfs, reiserfs, xfs. Some of >>>>> them have very appealing feature-sets (like compression for example, >>>>> and we all know how greedy is couchdb for disk space). >>>>> And I know that for example btrfs is not yet "recommended for >>>>> production". But its time is coming. From what I see, Ubuntu 10.10 >>>>> works flawlessly on btrfs. >>>>> So I'd be happy if we have some discussion on the topic, instead of >>>>> "everybody uses ext4, just use it" kind of stuff :). >>>>> Couchdb was "alpha software" for years, and we all used it in >>>>> production, so we are not afraid of alpha/beta software, as long as >>>>> it's good :) >>>> >>> >>> >>> >>> -- >>> http://www.readwriteweb.com/about#tyler >>> >>> Ask me anything <http://tumble.pdxbrain.com/ask>! >>> >> >> >> >> -- >> Chris Anderson >> http://jchrisa.net >> http://couch.io >>
