[DRBD-user] drbd 8.3.12 cannot get syncer speed beyond 110MB/s

Maurits van de Lande M.vandeLande at VDL-Fittings.com
Wed Feb 1 13:36:44 CET 2012

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


I have asked this question before for drbd 8.4.1 but I couldn't get proper write performance.
Currently I downgraded drbd to 8.3.12 but I cannot get the syncer speed above 1Gb/s or 110MB/s.

When I test the disk throughput with
#dd if=/dev/zero of=/VM/test bs=512M count=1  oflag=direct 
I get a speed around 500MB/s
(It's an all SSD raid 5 array)
I installed a 10G network adapter and tested the connection with iperf and I get on average 7Gbit/s

This should all be sufficient for a drbd syncer speed >110MB/s.
I have set the "rate=200M" option for a 2Gbit/s rate

cat /proc/drbd shows
version: 8.3.12 (api:88/proto:86-96)
GIT-hash: e2a8ef4656be026bbae540305fcb998a5991090f build by dag at Build64R6, 2011-11-20 10:57:03
 0: cs:SyncSource ro:Primary/Primary ds:UpToDate/Inconsistent C r-----
    ns:176 nr:0 dw:0 dr:79839200 al:0 bm:4872 lo:0 pe:0 ua:20 ap:0 ep:1 wo:d oos:1470943696
        [>...................] sync'ed:  5.2% (1436468/1514432)M
        finish: 3:30:54 speed: 116,228 (109,212) K/sec

Only at the start the value of (200.000) K/sec is shown.

What can I do to get the 200MB/s syncer speed?

Best regards,

Maurits van de Lande

| Van de Lande BV. | Lissenveld 1 | 4941VK | Raamsdonksveer | the Netherlands |T +31 (0) 162 516000 | F +31 (0) 162 521417 | www.vdl-fittings.com |

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