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From Chris Anderson <jch...@apache.org>
Subject Re: Which filesystem is best for deploying couchdb and why?
Date Fri, 17 Sep 2010 19:22:55 GMT
On Thu, Sep 16, 2010 at 6:22 PM, Tyler Gillies <tyler@pdxbrain.com> 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 <randall.leeds@gmail.com>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 <akat.metin@gmail.com> 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

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