Which msg type and ceph version are you using?

Once we used 0.94.1 with async msg, we encountered similar issue.
Client was trying to connect a down monitor when it was just started
and this connection would hung there. This is because previous async
msg used blocking connection mode.

After we back ported non-blocking mode of async msg from higher ceph
version, we haven't encountered such issue yet.


Regards,
Zhi Zhang (David)
Contact: zhang.david2...@gmail.com
              zhangz.da...@outlook.com


On Fri, Dec 18, 2015 at 11:41 AM, Jevon Qiao <scaleq...@gmail.com> wrote:
> 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
>>
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