> -----Original Message----- > From: Ilya Dryomov [mailto:idryo...@gmail.com] > Sent: 24 October 2016 14:45 > To: Nick Fisk <n...@fisk.me.uk> > Cc: Yan, Zheng <uker...@gmail.com>; Gregory Farnum <gfar...@redhat.com>; > Zheng Yan <z...@redhat.com>; Ceph Users <ceph- > us...@lists.ceph.com> > Subject: Re: [ceph-users] Ceph and TCP States > > On Mon, Oct 24, 2016 at 11:50 AM, Nick Fisk <n...@fisk.me.uk> wrote: > >> -----Original Message----- > >> From: Ilya Dryomov [mailto:idryo...@gmail.com] > >> Sent: 24 October 2016 10:33 > >> To: Nick Fisk <n...@fisk.me.uk> > >> Cc: Yan, Zheng <uker...@gmail.com>; Gregory Farnum > >> <gfar...@redhat.com>; Zheng Yan <z...@redhat.com>; Ceph Users <ceph- > >> us...@lists.ceph.com> > >> Subject: Re: [ceph-users] Ceph and TCP States > >> > >> On Mon, Oct 24, 2016 at 11:29 AM, Nick Fisk <n...@fisk.me.uk> wrote: > >> >> -----Original Message----- > >> >> From: Yan, Zheng [mailto:uker...@gmail.com] > >> >> Sent: 24 October 2016 10:19 > >> >> To: Gregory Farnum <gfar...@redhat.com> > >> >> Cc: Nick Fisk <n...@fisk.me.uk>; Zheng Yan <z...@redhat.com>; Ceph > >> >> Users <ceph-users@lists.ceph.com> > >> >> Subject: Re: [ceph-users] Ceph and TCP States > >> >> > >> >> X-Assp-URIBL failed: 'ceph-users-ceph.com'(black.uribl.com ) > >> >> X-Assp-Spam-Level: ***** > >> >> X-Assp-Envelope-From: uker...@gmail.com > >> >> X-Assp-Intended-For: n...@fisk.me.uk > >> >> X-Assp-ID: ASSP.fisk.me.uk (47730-03772) > >> >> X-Assp-Version: 1.9.1.4(1.0.00) > >> >> > >> >> On Sat, Oct 22, 2016 at 4:14 AM, Gregory Farnum <gfar...@redhat.com> > >> >> wrote: > >> >> > On Fri, Oct 21, 2016 at 7:56 AM, Nick Fisk <n...@fisk.me.uk> wrote: > >> >> >>> -----Original Message----- > >> >> >>> From: ceph-users [mailto:ceph-users-boun...@lists.ceph.com] On > >> >> >>> Behalf Of Haomai Wang > >> >> >>> Sent: 21 October 2016 15:40 > >> >> >>> To: Nick Fisk <n...@fisk.me.uk> > >> >> >>> Cc: ceph-users@lists.ceph.com > >> >> >>> Subject: Re: [ceph-users] Ceph and TCP States > >> >> >>> > >> >> >>> > >> >> >>> > >> >> >>> On Fri, Oct 21, 2016 at 10:31 PM, Nick Fisk > >> >> >>> <mailto:n...@fisk.me.uk> wrote: > >> >> >>> > -----Original Message----- > >> >> >>> > From: ceph-users > >> >> >>> > [mailto:mailto:ceph-users-boun...@lists.ceph.com] > >> >> >>> > On Behalf Of Haomai Wang > >> >> >>> > Sent: 21 October 2016 15:28 > >> >> >>> > To: Nick Fisk <mailto:n...@fisk.me.uk> > >> >> >>> > Cc: mailto:ceph-users@lists.ceph.com > >> >> >>> > Subject: Re: [ceph-users] Ceph and TCP States > >> >> >>> > > >> >> >>> > > >> >> >>> > > >> >> >>> > On Fri, Oct 21, 2016 at 10:19 PM, Nick Fisk > >> >> >>> > <mailto:mailto:n...@fisk.me.uk> wrote: > >> >> >>> > Hi, > >> >> >>> > > >> >> >>> > I'm just testing out using a Ceph client in a DMZ behind a > >> >> >>> > FW from the main Ceph cluster. One thing I have noticed is > >> >> >>> > that if the state table on the FW is emptied maybe by > >> >> >>> > restarting it or just clearing the state table...etc. Then > >> >> >>> > the Ceph client will hang for a > >> >> long time as the TCP session can no longer pass through the FW and just > >> >> gets blocked instead. > >> >> >>> > > >> >> >>> > This "FW" is linux firewall or hardware FW? > >> >> >>> > >> >> >>> PFSense running on dedicated HW. Eventually they will be in a > >> >> >>> HA pair so states should persist, but trying to work around > >> >> >>> this for > >> >> now. > >> >> >>> Bit annoying having CephFS lock hard for 15 minutes even though the > >> >> >>> network connection only went down for a few > seconds. > >> >> >>> > >> >> >>> hmm, I'm not familiar with this fw. And from my view, > >> >> >>> whether RST packet sent is decided by FW. But I think you can > >> >> >>> try "/proc/sys/net/ipv4/tcp_keepalive_time", if FW reset tcp > >> >> >>> session, tcp > >> >> keepalive should detect and send a rst. > >> >> >> > >> >> >> Yeah I think that’s where the problem lies. Most Firewalls tend > >> >> >> to silently drop denied packets without sending RST's, so Ceph > >> >> effectively just thinks that its experiencing packet loss and will > >> >> never retry until the 15 minute timeout period is up. Am I right > >> >> in thinking I can't tune down this parameter for a CephFS kernel > >> client as it doesn't use the ceph.conf file? > >> >> > > >> >> > The kernel client has a lot of mount options and can be > >> >> > configured in a few ways via debugfs et al; I think there's a > >> >> > setting for the timeout as well. If you can't find it, I'm sure > >> >> > Zheng knows. :) -Greg > >> >> > >> >> So far, there is no mount option to control keepalive time for > >> >> client-to-mds connection. > >> > > >> > I think, although can't be 100%, that most of the problem is around > >> > client<->mon traffic. I'm pretty sure I saw a timeout to one of the > >> mons flash up on the screen just before everything sprung back into life. > >> > >> Which kernel is this? kernel client <-> mon session has a 30 second > >> keepalive timeout in recent kernels. > > > > Kernel is 4.8. > > > > I'm certainly not seeing connectivity come back in 30 seconds, can't be > > sure on the 15 minutes I stated above, but it's around that > figure. I also don't see any new TCP sessions established on the firewall, so > it doesn't look like it's trying to establish a new TCP > connection after 30s either. A reboot of the client is currently the fastest > way to get everything working again. > > Do you see anything in /sys/kernel/debug/ceph/<fsid>/osdc or mdsc when this > happens? > > Can you try reproducing with krbd? If it's a mon session problem, it should > behave the same...
It might take me a day or two until I am in the position to be able to take everything offline again. But when I can I will find the answers to those questions and also grap some tcpdumps. > > Thanks, > > Ilya _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
