Re: is hosting a read-mostly git repo on a distributed file system practical?

From: Shawn Pearce <spearce@spearce.org>
Date: Apr 13, 2011, 02:06 UTC
Message-ID: <BANLkTimPYchTXiMpnmE47kxiXvJ_c6QZ9Q@mail.gmail.com>
In-Reply-To: <BANLkTiniGcRAHbt5LP2NVhE+c8grOr5sLA@mail.gmail.com>

On Tue, Apr 12, 2011 at 21:40, Jon Seymour <jon.seymour@gmail.com> wrote:

> Is it practical to host a read-mostly git repo on a WAN-based
> distributed file system?

Usually not. But test it and find out?

Show 6 quoted lines

> The idea is that most developers would use the DFS-based repo to track
> the tip of the development stream, but only the integrator would
> publish updates to the DFS-based repo.
>
> As such, the need to repack the DFS-based repo will be somewhat, but
> not completely, reduced.

Serving git clone is basically a repack operation when run over git://, http:// or SSH. If the DFS was mounted as a local filesystem, git clone would turn into a cpio to copy the directory contents. I'm not sure if that is what you are suggesting to do here or not.

> Is this going to be practical, or are whole of repo operations
> eventually going to kill me because of latency and bandwidth issues
> associated with use of the DFS?

Latency is a problem. The Git pack file has decent locality, but there are some things that could still stand to be improved. It really doesn't work well unless the pack is held completely in the machine's memory.

-- 
Shawn.