From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jevon Qiao Subject: Re: Client still connect failed leader after that mon down Date: Fri, 18 Dec 2015 11:41:13 +0800 Message-ID: <56738059.3070505@gmail.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-pf0-f169.google.com ([209.85.192.169]:35689 "EHLO mail-pf0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752205AbbLRDlZ (ORCPT ); Thu, 17 Dec 2015 22:41:25 -0500 Received: by mail-pf0-f169.google.com with SMTP id v86so41610173pfa.2 for ; Thu, 17 Dec 2015 19:41:25 -0800 (PST) In-Reply-To: Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Sage Weil , Jaze Lee Cc: ceph-devel@vger.kernel.org On 17/12/15 21:27, Sage Weil wrote: > On Thu, 17 Dec 2015, Jaze Lee wrote: >> Hello cephers: >> In our test, there are three monitors. We find client run ceph >> command will slow when the leader mon is down. Even after long time, a >> client run ceph command will also slow in first time. >> >From strace, we find that the client first to connect the leader, then >> after 3s, it connect the second. >> After some search we find that the quorum is not change, the leader is >> still the down monitor. >> Is that normal? Or is there something i miss? > It's normal. Even when the quorum does change, the client doesn't > know that. It should be contacting a random mon on startup, though, so I > would expect the 3s delay 1/3 of the time. That's because client randomly picks up a mon from Monmap. But what we observed is that when a mon is down no change is made to monmap(neither the epoch nor the members). Is it the culprit for this phenomenon? Thanks, Jevon > A long-standing low-priority feature request is to have the client contact > 2 mons in parallel so that it can still connect quickly if one is down. > It's requires some non-trivial work in mon/MonClient.{cc,h} though and I > don't think anyone has looked at it seriously. > > sage > > -- > 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