Re: [Moosefs-users] Need more detailed documents on moosefs

[Jun C. P. <jun...@gm...>]

Just more clarifications for those who can answer my questions:

> In particular, I am very interested in the consistency model
> comparison between them.

The main reason to need to know the detailed consistency model is that
the consistency model typically implies associated requirements on
applications. The GFS paper clearly describes what guarantees in terms
of concurrency are provides by GFS, thereby what is required for
applications. Especially, for update requests of files (chunks) with
concurrent reads from multiple users, there must be a clear
description on how they will be synchronized. Otherwise, it is too
risky to make applications that may cause unknown problems. Of course,
if no worries needed on MFS, it would be more than welcome, though.

-Jun

On Wed, Jan 12, 2011 at 11:35 AM, Jun Cheol Park
<jun...@gm...> wrote:
> Hi,
>
> While reading the original full paper on the Google file system (GFS)
> SOSP'03, I got a strong impression that MFS inherited almost all the
> main philosophies of GFS (chunk-based data pipeline, copy-on-write,
> lazy deletion, in-memory metadata managment, data integrity using
> checksum, etc). Even all the terminologies (metadata server,
> chunkserver, etc) seemed to be borrowed from GFS. However, I could not
> find any document on MooseFS mentioning that MFS was motivated by GFS.
> So I don't know if MFS was indeed motivated by GFS or not.
>
> Anyway, even with such lots of similarities that I found, there are
> some interesting differences between them. For instance, MFS is
> POSIX-compliant while GFS not. MFS uses a random placement of replicas
> vs GFS uses the concept of "closest chunkserver first."
>
> However, it was not easy to find what other differences could be and
> what advantages of MFS over GFS exist in the current implementation of
> MFS. In particular, I am very interested in the consistency model
> comparison between them.
>
> Is there anyone that can give me comments on my curiosities or
> introduce some documents that describe the differences between them?
>
> Thanks in advance,
>
> -Jun
>