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From: Dan Mick <dan.mick@inktank.com>
To: hemant surale <hemant.surale@gmail.com>
Cc: ceph-devel@vger.kernel.org
Subject: Re: Ho to identify location of Primary Copy Of Obj ?
Date: Tue, 25 Sep 2012 13:34:26 -0700	[thread overview]
Message-ID: <50621552.2050900@inktank.com> (raw)
In-Reply-To: <CAGfy=6mvjOUh8jV8EaSZXK=o-6+a5fdFTvNF6WrXcqmF4mwRog@mail.gmail.com>

Hemant:

Yes, you can.  Use ceph osd getmap -o <file> to get the OSD map, and 
then use osdmaptool --find-object-map <objectname> <file> to output the
PG the object hashes to and the list of OSDs that PG maps to (primary 
first):

$ ceph osd getmap -o osdmap
got osdmap epoch 59
$ osdmaptool --test-map-object dmick.rbd osdmap
osdmaptool: osdmap file 'osdmap'
  object 'dmick.rbd' -> 0.69c8 -> [3,1]

shows dmick.rbd mapping to pg 0.69c8, which in turn maps to OSDs 3 and 
1, 3 being the primary.

On 09/25/2012 02:30 AM, hemant surale wrote:
> Hi Community,
>            Is it possible to identify where exactly primary copy of obj
> is stored ? I am using crushmaps to use specific osds for data
> placement but i want to knw the primary capoy location. Or I need to
> replace pseudo random function by some deterministic function to guide
> ceph to utilize specific osd?
>
>
> Regards,
> Hemant Surale.
> --
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>

  reply	other threads:[~2012-09-25 20:34 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-09-25  9:30 Ho to identify location of Primary Copy Of Obj ? hemant surale
2012-09-25 20:34 ` Dan Mick [this message]
2012-09-25 21:29   ` Sage Weil
2012-09-26 10:59     ` hemant surale
2012-09-26  6:54   ` hemant surale
2012-09-26 15:21     ` Sage Weil
2012-09-26 21:53       ` Dan Mick
2012-09-26 23:41         ` Sage Weil
2012-09-27  5:11           ` Dan Mick

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