I would not call a ceph page, a random tuning tip. At least I hope they 
are not. NVMe-only with 100Gbit is not really a standard setup. I assume 
with such setup you have the luxury to not notice many optimizations. 

What I mostly read is that changing to mtu 9000 will allow you to better 
saturate the 10Gbit adapter, and I expect this to show on a low end busy 
cluster. Don't you have any test results of such a setup?




-----Original Message-----

Subject: Re: [ceph-users] Re: [External Email] Re: Ceph Nautius not 
working after setting MTU 9000

Don't optimize stuff without benchmarking *before and after*, don't 
apply random tuning tipps from the Internet without benchmarking them.

My experience with Jumbo frames: 3% performance. On a NVMe-only setup 
with 100 Gbit/s network.

Paul


--
Paul Emmerich

Looking for help with your Ceph cluster? Contact us at https://croit.io

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On Tue, May 26, 2020 at 7:02 PM Marc Roos <m.r...@f1-outsourcing.eu> 
wrote:




        Look what I have found!!! :)
        https://ceph.com/geen-categorie/ceph-loves-jumbo-frames/ 
        
        
        
        -----Original Message-----
        From: Anthony D'Atri [mailto:anthony.da...@gmail.com] 
        Sent: maandag 25 mei 2020 22:12
        To: Marc Roos
        Cc: kdhall; martin.verges; sstkadu; amudhan83; ceph-users; doustar
        Subject: Re: [ceph-users] Re: [External Email] Re: Ceph Nautius not 

        working after setting MTU 9000
        
        Quick and easy depends on your network infrastructure.  Sometimes 
it is 
        difficult or impossible to retrofit a live cluster without 
disruption.   
        
        
        > On May 25, 2020, at 1:03 AM, Marc Roos <m.r...@f1-outsourcing.eu> 

        wrote:
        > 
        > 
        > I am interested. I am always setting mtu to 9000. To be honest I 
        > cannot imagine there is no optimization since you have less 
interrupt 
        > requests, and you are able x times as much data. Every time there 

        > something written about optimizing the first thing mention is 
changing 
        
        > to the mtu 9000. Because it is quick and easy win.
        > 
        > 
        > 
        > 
        > -----Original Message-----
        > From: Dave Hall [mailto:kdh...@binghamton.edu]
        > Sent: maandag 25 mei 2020 5:11
        > To: Martin Verges; Suresh Rama
        > Cc: Amudhan P; Khodayar Doustar; ceph-users
        > Subject: [ceph-users] Re: [External Email] Re: Ceph Nautius not 
        > working after setting MTU 9000
        > 
        > All,
        > 
        > Regarding Martin's observations about Jumbo Frames....
        > 
        > I have recently been gathering some notes from various internet 
        > sources regarding Linux network performance, and Linux 
performance in 
        > general, to be applied to a Ceph cluster I manage but also to the 
rest 
        
        > of the Linux server farm I'm responsible for.
        > 
        > In short, enabling Jumbo Frames without also tuning a number of 
other 
        > kernel and NIC attributes will not provide the performance 
increases 
        > we'd like to see.  I have not yet had a chance to go through the 
rest 
        > of the testing I'd like to do, but  I can confirm (via iperf3) 
that 
        > only enabling Jumbo Frames didn't make a significant difference.
        > 
        > Some of the other attributes I'm referring to are incoming and 
        > outgoing buffer sizes at the NIC, IP, and TCP levels, interrupt 
        > coalescing, NIC offload functions that should or shouldn't be 
turned 
        > on, packet queuing disciplines (tc), the best choice of TCP 
slow-start 
        
        > algorithms, and other TCP features and attributes.
        > 
        > The most off-beat item I saw was something about adding IPTABLES 
rules 
        
        > to bypass CONNTRACK table lookups.
        > 
        > In order to do anything meaningful to assess the effect of all of 

        > these settings I'd like to figure out how to set them all via 
Ansible 
        > - so more to learn before I can give opinions.
        > 
        > -->  If anybody has added this type of configuration to Ceph 
Ansible,
        > I'd be glad for some pointers.
        > 
        > I have started to compile a document containing my notes.  It's 
rough, 
        
        > but I'd be glad to share if anybody is interested.
        > 
        > -Dave
        > 
        > Dave Hall
        > Binghamton University
        > 
        >> On 5/24/2020 12:29 PM, Martin Verges wrote:
        >> 
        >> Just save yourself the trouble. You won't have any real benefit 
from
        > MTU
        >> 9000. It has some smallish, but it is not worth the effort, 
problems,
        > and
        >> loss of reliability for most environments.
        >> Try it yourself and do some benchmarks, especially with your 
regular 
        >> workload on the cluster (not the maximum peak performance), then 
drop
        > the
        >> MTU to default ;).
        >> 
        >> Please if anyone has other real world benchmarks showing huge
        > differences
        >> in regular Ceph clusters, please feel free to post it here.
        >> 
        >> --
        >> Martin Verges
        >> Managing director
        >> 
        >> Mobile: +49 174 9335695
        >> E-Mail: martin.ver...@croit.io
        >> Chat: https://t.me/MartinVerges
        >> 
        >> croit GmbH, Freseniusstr. 31h, 81247 Munich
        >> CEO: Martin Verges - VAT-ID: DE310638492 Com. register: 
Amtsgericht 
        >> Munich HRB 231263
        >> 
        >> Web: https://croit.io
        >> YouTube: https://goo.gl/PGE1Bx
        >> 
        >> 
        >>> Am So., 24. Mai 2020 um 15:54 Uhr schrieb Suresh Rama
        >> <sstk...@gmail.com>:
        >> 
        >>> Ping with 9000 MTU won't get response as I said and it should 
be
        > 8972. Glad
        >>> it is working but you should know what happened to avoid this 
issue
        > later.
        >>> 
        >>>> On Sun, May 24, 2020, 3:04 AM Amudhan P <amudha...@gmail.com> 
        wrote:
        >>> 
        >>>> No, ping with MTU size 9000 didn't work.
        >>>> 
        >>>> On Sun, May 24, 2020 at 12:26 PM Khodayar Doustar
        > <dous...@rayanexon.ir>
        >>>> wrote:
        >>>> 
        >>>>> Does your ping work or not?
        >>>>> 
        >>>>> 
        >>>>> On Sun, May 24, 2020 at 6:53 AM Amudhan P 
<amudha...@gmail.com>
        > wrote:
        >>>>> 
        >>>>>> Yes, I have set setting on the switch side also.
        >>>>>> 
        >>>>>> On Sat 23 May, 2020, 6:47 PM Khodayar Doustar,
        > <dous...@rayanexon.ir>
        >>>>>> wrote:
        >>>>>> 
        >>>>>>> Problem should be with network. When you change MTU it 
should be
        >>>> changed
        >>>>>>> all over the network, any single hup on your network should 

        >>>>>>> speak
        > and
        >>>>>>> accept 9000 MTU packets. you can check it on your hosts 
with
        >>> "ifconfig"
        >>>>>>> command and there is also equivalent commands for other
        >>>> network/security
        >>>>>>> devices.
        >>>>>>> 
        >>>>>>> If you have just one node which it not correctly configured 
for
        > MTU
        >>>> 9000
        >>>>>>> it wouldn't work.
        >>>>>>> 
        >>>>>>> On Sat, May 23, 2020 at 2:30 PM si...@turka.nl 
<si...@turka.nl>
        >>> wrote:
        >>>>>>>> Can the servers/nodes ping eachother using large packet 
sizes? 
        >>>>>>>> I
        >>> guess
        >>>>>>>> not.
        >>>>>>>> 
        >>>>>>>> Sinan Polat
        >>>>>>>> 
        >>>>>>>>> Op 23 mei 2020 om 14:21 heeft Amudhan P 
<amudha...@gmail.com>
        > het
        >>>>>>>> volgende geschreven:
        >>>>>>>>> In OSD logs "heartbeat_check: no reply from OSD"
        >>>>>>>>> 
        >>>>>>>>>> On Sat, May 23, 2020 at 5:44 PM Amudhan P
        > <amudha...@gmail.com>
        >>>>>>>> wrote:
        >>>>>>>>>> Hi,
        >>>>>>>>>> 
        >>>>>>>>>> I have set Network switch with MTU size 9000 and also in 
my
        >>> netplan
        >>>>>>>>>> configuration.
        >>>>>>>>>> 
        >>>>>>>>>> What else needs to be checked?
        >>>>>>>>>> 
        >>>>>>>>>> 
        >>>>>>>>>>> On Sat, May 23, 2020 at 3:39 PM Wido den Hollander <
        >>> w...@42on.com
        >>>>>>>> wrote:
        >>>>>>>>>>> 
        >>>>>>>>>>> 
        >>>>>>>>>>>> On 5/23/20 12:02 PM, Amudhan P wrote:
        >>>>>>>>>>>> Hi,
        >>>>>>>>>>>> 
        >>>>>>>>>>>> I am using ceph Nautilus in Ubuntu 18.04 working fine 
wit
        > MTU
        >>>> size
        >>>>>>>> 1500
        >>>>>>>>>>>> (default) recently i tried to update MTU size to 9000.
        >>>>>>>>>>>> After setting Jumbo frame running ceph -s is timing 
out.
        >>>>>>>>>>> Ceph can run just fine with an MTU of 9000. But there 
is
        >>> probably
        >>>>>>>>>>> something else wrong on the network which is causing 
this.
        >>>>>>>>>>> 
        >>>>>>>>>>> Check the Jumbo Frames settings on all the switches as 
well
        > to
        >>>> make
        >>>>>>>> sure
        >>>>>>>>>>> they forward all the packets.
        >>>>>>>>>>> 
        >>>>>>>>>>> This is definitely not a Ceph issue.
        >>>>>>>>>>> 
        >>>>>>>>>>> Wido
        >>>>>>>>>>> 
        >>>>>>>>>>>> regards
        >>>>>>>>>>>> Amudhan P
        >>>>>>>>>>>> _______________________________________________
        >>>>>>>>>>>> ceph-users mailing list -- ceph-users@ceph.io To 
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