[DRBD-user] speed problems

[Volodymyr Litovka]

Hi Rick,

originating host generate flows to all nodes where replica will be
stored, e.g. if you've configured three replicas, then:

- in general, at least two copies of data will pass the NIC
- but if you're using volume on 'diskless' host, three copies of data
will pass the NIC

similar arithmetic apply to two replicas.

Please see my recent message with subject 'drbd & multicast'.

On 03.04.2020 18:55, Rick Gutierrez wrote:
> hi list, i am installing drbd 8.4.x in centos 7 in a couple of boxes,
> i need to replicate my mail server, but i am having speed problems in
> the replication, i have tried different options within the
> configuration and without success.
>
> I have my network at 1gb ethernet, my switch is cisco 2960-S, I am
> replicating 1.3TB on 7200RPM disks, but the speed is terrible, very
> slow.
>
> version of rpm
> drbd84-utils-9.6.0-1.el7.elrepo.x86_64
> kmod-drbd84-8.4.11-1.1.el7_6.elrepo.x86_64
> drbd84-utils-sysvinit-9.6.0-1.el7.elrepo.x86_64
>
> my setting:
>
> disk {
>
>          c-plan-ahead 0;
>                  on-io-error detach;
> no-disk-flushes ;
>          no-disk-barrier;
>                  c-min-rate 90M;
> c-max-rate 120M;
>
> net {
>
>          allow-two-primaries;
>
>          cram-hmac-alg sha1;
>
>          shared-secret  "C2qz2wsx";
>
> max-buffers             36k;
>
>          sndbuf-size            1024k ;
>
>          rcvbuf-size            2048k;
>
>      }
>
> any idea?
>
--
Volodymyr Litovka
   "Vision without Execution is Hallucination." -- Thomas Edison