On Fri, Sep 20, 2013 at 11:44 PM, Gregory Farnum <[email protected]> wrote:

> [ Re-added the list — please keep emails on there so everybody can
> benefit! ]
>
> On Fri, Sep 20, 2013 at 12:24 PM, Serge Slipchenko
> <[email protected]> wrote:
> >
> >
> >
> > On Fri, Sep 20, 2013 at 5:59 PM, Gregory Farnum <[email protected]>
> wrote:
> >>
> >> On Fri, Sep 20, 2013 at 6:40 AM, Serge Slipchenko
> >> <[email protected]> wrote:
> >> > Hi,
> >> >
> >> > I'm using CephFS 0.67.3 as a backend for Hypertable and ElasticSearch.
> >> > Active reading/writing to the cephfs causes uncontrolled OSD memory
> >> > growth
> >> > and at the final stage swapping and server unavailability.
> >>
> >> What kind of memory growth are you seeing?
> >
> > 10-20Gb
> >
> >>
> >> > To keep the cluster in working condition I have to restart OSD's with
> >> > excessive memory consumption.
> >> > This is definitely wrong, but I hope it will help to understand
> problem.
> >> >
> >> > One of the nodes scrubbing, go series of faults from MON and OSD is
> >> > restarted by the memory guard script.
> >>
> >> What makes you think a monitor is involved? The log below doesn't look
> >> like a monitor unless you've done something strange with your config
> >> (wrong ports).
> >
> > Yes, I am somewhat inaccurate. I mean 144.76.13.103  is also a monitor
> node.
> >
> >>
> >> > 2013-09-20 10:54:39.901871 7f74374a0700  0 log [INF] : 5.e0 scrub ok
> >> > 2013-09-20 10:56:50.563862 7f74374a0700  0 log [INF] : 1.27 scrub ok
> >> > 2013-09-20 11:00:03.159553 7f742c826700  0 -- 5.9.136.227:6801/1389>>
> >> > 5.9.136.227:6805/1510 pipe(0x97fcc80 sd=72 :6801 s=0 pgs=0 cs=0 l=0
> >> > c=0x9889000).accept connect_seq 2 vs existing 1 stat
> >> > e standby
> >> > 2013-09-20 11:00:04.935305 7f7433685700  0 -- 5.9.136.227:6801/1389>>
> >> > 144.76.13.103:6801/1771 pipe(0x963b000 sd=63 :56878 s=2 pgs=41599
> cs=553
> >> > l=0
> >> > c=0x9679160).fault with nothing to send, go
> >> > ing to standby
> >> > 2013-09-20 11:00:04.986654 7f742c725700  0 -- 5.9.136.227:0/1389 >>
> >> > 144.76.13.103:6803/1771 pipe(0x9859780 sd=240 :0 s=1 pgs=0 cs=0 l=1
> >> > c=0xb2b1b00).fault
> >> > 2013-09-20 11:00:04.986662 7f7430157700  0 -- 5.9.136.227:0/1389 >>
> >> > 144.76.13.103:6802/1771 pipe(0xbbf4780 sd=144 :0 s=1 pgs=0 cs=0 l=1
> >> > c=0xa89b000).fault
> >> > 2013-09-20 11:03:23.499091 7f7432379700  0 -- 5.9.136.227:6801/1389>>
> >> > 144.76.13.103:6801/17989 pipe(0xb2d0500 sd=230 :6801 s=0 pgs=0 cs=0
> l=0
> >> > c=0xa89b6e0).accept connect_seq 46 vs existing 0
> >> >  state connecting
> >> > 2013-09-20 11:03:23.499704 7f7432379700  0 -- 5.9.136.227:6801/1389>>
> >> > 144.76.13.103:6801/17989 pipe(0xb2d0500 sd=230 :6801 s=1 pgs=2107
> cs=47
> >> > l=0
> >> > c=0xf247580).fault
> >> > 2013-09-20 11:03:23.505559 7f7431369700  0 -- 5.9.136.227:6801/1389>>
> >> > 144.76.13.103:6801/17989 pipe(0x9874c80 sd=230 :6801 s=0 pgs=0 cs=0
> l=0
> >> > c=0xa89b000).accept connect_seq 1 vs existing 47
> >> >  state connecting
> >> > 2013-09-20 11:15:03.239657 7f742c826700  0 -- 5.9.136.227:6801/1389>>
> >> > 5.9.136.227:6805/1510 pipe(0x97fcc80 sd=72 :6801 s=2 pgs=1297 cs=3
> l=0
> >> > c=0x9855b00).fault with nothing to send, going to
> >> >  standby
> >> >
> >> > A similar chain of events is repeated on different servers with
> >> > regularity
> >> > of 2 hours.
> >> >
> >> > It looks similar to the old bug http://tracker.ceph.com/issues/3883 ,
> >> > but
> >> > I'm using plain log files.
> >>
> >> Not if your issue is correlated with writes rather than scrubs. :)
> >
> > Could those problems be caused by slow network?
> >
> >>
> >> > Is it anything well known or something new?
> >>
> >> Nobody's reported anything like it yet.
> >> In addition to the above, we'll also need to know about your cluster.
> >> How many nodes, what does each look like, what's your network look
> >> like, what OS and where did you get your Ceph packages?
> >
> > I have 8 servers connected via 1Gb network, but for some servers actual
> > speed is 100-200Mb.
>
> Well, yeah, that'll do it. 200Mb/s is only ~25MB/s, which is much
> slower than your servers can write to disk. So your machines with
> faster network are ingesting data and putting it on disk much more
> quickly than they can replicate it to the servers with slower network
> connections and the replication messages are just getting queued up in
> RAM. Ceph is designed so you can make it work with async hardware but
> making it work well with an async network is going to be more
> challenging.
>
Yes, it looks like servers that have 800Mb and higher connections never
have memory problems.


> You can play around with a couple different things to try and make this
> better:
> 1) Make the weight of the nodes proportional to their bandwidth.
>
Am I correct that lower weight means less I/O impact?


> 2) Play around with the message throttlers, especially for the
> clients. The aggregate amount of in-progress data the servers will
> allow in from clients is bounded by this value (multiplied by number
> of servers, etc).
> -Greg
>

-- 
Kind regards, Serge Slipchenko
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