[DRBD-user] Doc update and Sync performance

Josh Aune luken at fusionio.com
Tue Dec 29 23:56:17 CET 2009

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


Attached is a patch for the users guide.

Also, I'm having an issue with sync performance.  I have DRBD setup between two hosts using SRP.  Under optimal conditions I'm able to achieve a 500+ MB/s write speed, but during the initial sync after the DRBD device is created the sync proceeds at less than 100 MB/s.  Below is the config file.  Am I missing anything needed to bump up the initial sync speed?

Also, all bytes on the drives on both side are zeros, so the limitation seems to be in the crc32c processing.


common {
  protocol C;
  disk {
  net {
  syncer {
    rate 800M;
    csums-alg crc32c;
    verify-alg crc32c;
  startup {
    become-primary-on both;
resource fioa {
  on l1 {
    address    sdp;
    device     /dev/drbd1;
    disk       /dev/fioa;
    meta-disk  internal;
  on l2 {
    address    sdp;
    device     /dev/drbd1;
    disk       /dev/fioa;
    meta-disk  internal;


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