From: Joao Eduardo Luis <joao.luis@inktank.com>
To: Wido den Hollander <wido@widodh.nl>
Cc: "Chen, Xiaoxi" <xiaoxi.chen@intel.com>,
"Moore, Shawn M" <smmoore@catawba.edu>,
"ceph-devel@vger.kernel.org" <ceph-devel@vger.kernel.org>
Subject: Re: Crushmap Design Question
Date: Wed, 09 Jan 2013 15:00:47 +0000 [thread overview]
Message-ID: <50ED861F.3040703@inktank.com> (raw)
In-Reply-To: <50ED3175.8010304@widodh.nl>
On 01/09/2013 08:59 AM, Wido den Hollander wrote:
> Hi,
>
> On 01/09/2013 01:53 AM, Chen, Xiaoxi wrote:
>> Hi，
>> Setting rep size to 3 only make the data triple-replication, that means when you "fail" all OSDs in 2 out of 3 DCs, the data still accessable.
>> But Monitor is another story, for monitor clusters with 2N+1 nodes, it require at least N+1 nodes alive, and indeed this is why you Ceph failed.
>> It looks to me this discipline make it hard to design a proper deployment which is robust in DC outage. But hoping for inputs from community,how to make Monitor cluster reliable.
>>
>
> From what I understand he didn't kill the second mon, still leaving 2
> out of 3 mons running.
Indeed. A good hint that this is the case is this bit of Shawn's message:
>> When I fail a datacenter (including 1 of 3 mon's) I eventually get:
>> 2013-01-08 13:58:54.020477 mon.0 [INF] pgmap v2712139: 7104 pgs: 7104 active+degraded; 60264 MB data, 137 GB used, 13570 GB / 14146 GB avail; 16362/49086 degraded (33.333%)
>>
>> At this point everything is still ok. But when I fail the 2nd datacenter (still leaving 2 out of 3 mons running) I get:
>> 2013-01-08 14:01:25.600056 mon.0 [INF] pgmap v2712189: 7104 pgs: 7104 incomplete; 60264 MB data, 137 GB used, 13570 GB / 14146 GB avail
If you still manage to get these messages, it means your monitors are
still handling and answering requests, and that only happens when you
have a quorum :)
-Joao
--
To unsubscribe from this list: send the line "unsubscribe ceph-devel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
next prev parent reply other threads:[~2013-01-09 15:00 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-08 20:20 Crushmap Design Question Moore, Shawn M
2013-01-09 0:53 ` Chen, Xiaoxi
2013-01-09 8:59 ` Wido den Hollander
2013-01-09 14:41 ` Moore, Shawn M
2013-01-09 15:00 ` Joao Eduardo Luis [this message]
2013-01-10 21:34 ` Gregory Farnum
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=50ED861F.3040703@inktank.com \
--to=joao.luis@inktank.com \
--cc=ceph-devel@vger.kernel.org \
--cc=smmoore@catawba.edu \
--cc=wido@widodh.nl \
--cc=xiaoxi.chen@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.