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From: Martin Fick <mogulguy@yahoo.com>
To: Sage Weil <sage@newdream.net>
Cc: "Cláudio Martins" <ctpm@ist.utl.pt>, ceph-devel@vger.kernel.org
Subject: Re: RBD/OSD questions
Date: Thu, 6 May 2010 15:28:42 -0700 (PDT)	[thread overview]
Message-ID: <719233.66260.qm@web36101.mail.mud.yahoo.com> (raw)

--- On Thu, 5/6/10, Sage Weil <sage@newdream.net> wrote:
> The image is striped over objects, _then_ the objects are
> replicated across OSDs.  Objects themselves aren't striped.
> 
> For example, if an image is striped over objects A B C D E
> F, each 4MB, you might end up with
> 
> osd0: A  B' C  D  E' F'
> osd1: A' B  C' D' E  F
> 
> where A is the primary copy, A' is the replica, etc.

Yes, I see now, much clearer, thanks.

So, as long as each object has one copy on each OSD it 
should be safe.  And there might be some hash based 
extra non-perfect stripping as a benefit.  Then, yeah,
it does seem like it would be hard to find a very 
unbalanced workload on a heterogeneous OSD (even with 
a 2 node cluster).  Cool.

Thanks,

-Martin



      
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             reply	other threads:[~2010-05-06 22:28 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-05-06 22:28 Martin Fick [this message]
  -- strict thread matches above, loose matches on Subject: below --
2010-05-06 21:02 RBD/OSD questions Martin Fick
2010-05-06 21:22 ` Sage Weil
2010-05-06 21:24 ` Cláudio Martins
2010-05-06 21:31   ` Sage Weil
2010-05-06 21:41     ` Martin Fick
2010-05-06 21:54       ` Gregory Farnum
2010-05-06 22:20       ` Sage Weil
2010-05-07 16:38         ` Andreas Grimm
2010-05-07 16:43           ` Sage Weil
2010-05-11  8:39             ` Anton
2010-05-11 16:26               ` Sage Weil
2010-05-06 16:07 Martin Fick
2010-05-06 17:14 ` Sage Weil

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