[DRBD-user] drbd read/write performance

[Mia Lueng]

Hi All:
I setup a drbd device on a storage . Its write performance can reach
to 300MB/s tested by dd. But when I setup a drbd device on it , use dd
to test its write performance (peer node does not connect). The test
result is only 40MB/s.  drbd version is 8.3.13.   And the read
performance is also very pool(40MB/s).

here is the configuration


resource drbd0 {
    protocol               A;
    on c-160 {
        device           /dev/drbd0 minor 0;
        disk             /dev/hadrvg/edrbd;
        address          ipv4 10.62.100.160:7700;
        meta-disk        internal;
    }
    on c-191 {
        device           /dev/drbd0 minor 0;
        disk             /dev/hadrvg/edrbd;
        address          ipv4 10.62.100.191:7700;
        meta-disk        internal;
    }
    net {
        ping-timeout     100;
        ping-int         100;
        data-integrity-alg crc32c;
        max-buffers      8000;
        max-epoch-size   8000;
        unplug-watermark  16;
        sndbuf-size        0;
    }
    disk {
        on-io-error      pass_on;
    }
    syncer {
        rate             1000M;
        csums-alg        md5;
        verify-alg       md5;
        c-plan-ahead      20;
        c-fill-target      0;
        c-delay-target    30;
    }
}