[Gluster-devel] Re: AFR + unify + namespace question

[Krishna Srinivas]

Brandon,

Thats how unify and afr are used to give redundancy + aggregation.
I hope you answered yourself here. in case there is something still
confusing, please mail back.

Krishna

On Sun, May 4, 2008 at 12:32 PM, Brandon Lamb <brandonlamb at gmail.com> wrote:
>
> On Sat, May 3, 2008 at 3:26 PM, Brandon Lamb <brandonlamb at gmail.com> wrote:
>  > On Sat, May 3, 2008 at 2:56 PM, Brandon Lamb <brandonlamb at gmail.com> wrote:
>  > >
>  > > On Sat, May 3, 2008 at 2:50 PM, Brandon Lamb <brandonlamb at gmail.com> wrote:
>  > > > I couldnt find anything related to this with a quick search.
>  > > >
>  > > > Lets take a case where we have 3 data servers, so we do AFR using
>  > > > unify. For unify we specify a namespace volume that exists on lets say
>  > > > server1.
>  > > >
>  > > > Ok so what happens when server1 goes down, now there is no namespace.
>  > > > What are the implications and is there a common solution to avoid
>  > > > this?
>  > >
>  > > http://gluster.org/docs/index.php/Aggregating_Three_Storage_Servers_with_Unify
>  > >
>  > > Ok so I started to attempt to create a 3 server 2 client setup. I
>  > > thought I would use 3 servers and i would only want 2 copies of files.
>  > > I thought to do this you needed afr + unify.
>  > >
>  > > However, AFR uses the number of servers as the number of copies, so
>  > > even using 3 servers I dont see a reason to use unify? Wont it just
>  > > send every write to all 3 servers anyway? So what is unify doing in
>  > > the example?
>  > >
>  > > Is that just a bad example that I am trying to follow?
>  >
>  > http://gluster.org/docs/index.php/Understanding_Unify_Translator
>  >
>  > I just finished reading the very bottom of this page. So what I got
>  > from that page is that if the server which holds the namespace goes
>  > down, something bad will happen?
>  >
>  > So what is the "recommended" solution for this? Have a seperate
>  > machine that does nothing export only a name space directory? At least
>  > until 1.4 and having the addition of distributed namespace?
>
>  http://www.gluster.org/docs/index.php/Unify_over_AFR
>
>  Ok wow either im totally blind or this was just added recently?
>  EXACTLY what I was looking for minus any explanation or details about
>  it, but I understand what it is doing. Very cool! afr the namespace
>  duh.
>
>
>
>
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