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CEPH/RDMA + Openstack


Hi Volodymyr - 

When I was testing and benchmarking, it was outside of an OpenStack context.

Iâ??d be interested to know whether you saw a performance uplift.  Are you using RDMA for both front-side and replication traffic?

Best wishes,
Stig


> On 28 Aug 2019, at 10:27, Volodymyr Litovka <doka.ua at gmx.com> wrote:
> 
> Hi Stig,
> 
> the main question is - whether you tested it with Openstack and all
> components works? Because regarding Ceph itself - we're using Mellanox
> ConnectX-4LX cards and found that Ceph works fine with RoCE in LAG
> configuration.
> 
>> There is potential here
> 
> Yes, agree with you. That's why we're trying to be ready for future
> improvements :) I guess that since Ceph supports RDMA officially, Redhat
> (as owner of Ceph) will sell it and, thus, will improve support.
> 
> Thank you.
> 
> On 28.08.2019 11:42, Stig Telfer wrote:
>> Hi there -
>> 
>>> On 28 Aug 2019, at 08:58, Volodymyr Litovka <doka.ua at gmx.com> wrote:
>>> does anyone have experience using RDMA-enabled CEPH with Openstack? How
>>> stable is it? Whether all Openstack components (Nova, Cinder) works with
>>> such specific configuration of Ceph? Any issues which can affect overall
>>> system reliability?
>> Last time I looked at this (with pre-release Nautilus, about 9 months ago), I had mixed results.
>> 
>> There are four generally-available RDMA fabrics (Infiniband, RoCE, iWARP and OPA) and I had a go at all of them apart from iWARP.
>> 
>> RoCE worked for me but IB and OPA were troublesome to get working.  Thereâ??s some work contributed for iWARP support that introduces the RDMA connection manager (RDMACM), which I found also helped for IB and OPA.
>> 
>> There is potential here but in performance terms, I didnâ??t manage a thorough benchmarking and didnâ??t see conclusive proof of advantage.  Perhaps things have come on since I looked, but it wasnâ??t an obvious win at the time.  Iâ??d love to have another pop at it, but for lack of timeâ?¦
>> 
>> Cheers,
>> Stig
>> 
>> 
> 
> --
> Volodymyr Litovka
>  "Vision without Execution is Hallucination." -- Thomas Edison
> 
>