[DRBD-user] Really, Really Slow or Misunderstanding?

knebb at knebb.de knebb at knebb.de
Wed Jul 31 06:48:09 CEST 2019

Hi all,

I have a drbd device set up and it looks like it is running fine so far.
Just when watching /proc/drbd the resync seems to be really, really slow:

version: 8.4.11-1 (api:1/proto:86-101)
GIT-hash: 66145a308421e9c124ec391a7848ac20203bb03c build by mockbuild@,
2018-11-03 01:26:55

 1: cs:SyncTarget ro:Secondary/Secondary ds:Inconsistent/UpToDate A r-----
    ns:0 nr:285164 dw:285044 dr:0 al:0 bm:0 lo:2 pe:2 ua:2 ap:0 ep:1
wo:f oos:314127936
        [>....................] sync'ed:  0.1% (306764/307004)M
        finish: 188:23:50 speed: 444 (424) want: 1,160 K/sec

I have not added any special settings to my drbd setup, the *.conf file
just hass all setting marekedd out with "#". And the device file has the

resource drbd1 {
  protocol A;
  startup {become-primary-on backuppc2;}
  on backuppc1 {
    device /dev/drbd1;
    disk /dev/vdb;
    meta-disk internal;
  on backuppc2 {
    device /dev/drbd1;
    disk /dev/sdb;
    meta-disk internal;

As it runs over a slow WAN connection (the line is 10Mbit ) I do not
expect the transfer rate to be very high. But most of the time just
444K/sec? There is no really impressive other traffic on the line and a
bandwidth calculator tells me it should be done (for the approx
307.000MB) within close three days. But 188 hours are triple of the
calculated time!

Oh, and on the device itself there is nearly no IO at this stage.

Is there some miscalculation or misreading of the values from
/proc/drbd? How can I speed up the sync?

Thanks a lot!


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