[DRBD-user] Performance issues with drbd and nfs

Stephano-Shachter, Dylan dstathis at seas.harvard.edu
Thu Jun 9 20:47:06 CEST 2016

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


Bump.

Could really use some help if anyone has any ideas about how I might
improve performance.

On Mon, Jun 6, 2016 at 4:17 PM, Stephano-Shachter, Dylan <
dstathis at seas.harvard.edu> wrote:

> Hello all,
>
> I am building an HA NFS server using drbd and pacemaker. Everything is
> working well except I am getting lower write speeds than I would expect. I
> have been doing all of my benchmarking with bonnie++. I always get read
> speeds of about 112 MB/s which is just about saturating the network. When I
> perform a write, however, I get about 89 MB/s which is significantly slower.
>
> The weird thing is that if I run the test locally, on the server (not
> using nfs), I get 112 MB/s read. Also, if I run the tests over nfs but with
> the secondary downed via "drbdadm down name", then I also get 112 MB/s. I
> can't understand what is causing the bottleneck if it is not drbd
> replication or nfs.
>
> If anyone could help me to figure out what is slowing down the write
> performance if would be very helpful. My configs are
>
>
> --------------------drbd-config-----------------------------
>
>
> # /etc/drbd.conf
> global {
>     usage-count yes;
>     cmd-timeout-medium 600;
>     cmd-timeout-long 0;
> }
>
> common {
>     net {
>         protocol           C;
>         after-sb-0pri    discard-zero-changes;
>         after-sb-1pri    discard-secondary;
>         after-sb-2pri    disconnect;
>         max-buffers      8000;
>         max-epoch-size   8000;
>     }
>     disk {
>         resync-rate      1024M;
>     }
>     handlers {
>         pri-on-incon-degr "/usr/lib/drbd/notify-pri-on-incon-degr.sh;
> /usr/lib/drbd/notify-emergency-reboot.sh; echo b > /proc/sysrq-trigger ;
> reboot -f";
>         pri-lost-after-sb "/usr/lib/drbd/notify-pri-lost-after-sb.sh;
> /usr/lib/drbd/notify-emergency-reboot.sh; echo b > /proc/sysrq-trigger ;
> reboot -f";
>         local-io-error   "/usr/lib/drbd/notify-io-error.sh;
> /usr/lib/drbd/notify-emergency-shutdown.sh; echo o > /proc/sysrq-trigger ;
> halt -f";
>         split-brain      "/usr/lib/drbd/notify-split-brain.sh root";
>     }
> }
>
> # resource <res_name> on <host1>: not ignored, not stacked
> # defined at /etc/drbd.d/<res_name>.res:1
> resource <res_name> {
>     on <host2> {
>         device           /dev/drbd1 minor 1;
>         disk             /dev/sdb1;
>         meta-disk        internal;
>         address          ipv4 55.555.55.55:7789;
>     }
>     on <host1> {
>         device           /dev/drbd1 minor 1;
>         disk             /dev/sdb1;
>         meta-disk        internal;
>         address          ipv4 55.555.55.55:7789;
>     }
>     net {
>         allow-two-primaries  no;
>         after-sb-0pri    discard-zero-changes;
>         after-sb-1pri    discard-secondary;
>         after-sb-2pri    disconnect;
>     }
> }
>
>
>
> -----------------------nfs.conf-----------------------------
>
>
>
> MOUNTD_NFS_V3="yes"
> RPCNFSDARGS="-N 2"
> LOCKD_TCPPORT=32803
> LOCKD_UDPPORT=32769
> MOUNTD_PORT=892
> RPCNFSDCOUNT=48
> #RQUOTAD_PORT=875
> #STATD_PORT=662
> #STATD_OUTGOING_PORT=2020
> STATDARG="--no-notify"
>
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