On Sep 19, 2010, at 9:42 , Metin Akat wrote: > Hmm, then I start thinking that btrfs is really better than ext4, > especially if I want to do things like copy the files in order to > deploy (fast) another instance with already build view indexes.
Well, ext4 is considered more stable than btrfs, that has to count for something in your reasoning :-) How would btrfs help with fast copies? You would still need to transfer the files to another system, no? > And would the couchdb files compress well? Yup... Wout. > > On Sat, Sep 18, 2010 at 12:23 PM, Wout Mertens <[email protected]> wrote: >> 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 >>>> >> >>
