Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
/ 2005-08-17 22:10:28 +0200 \ Hans Holm: > First time connecting and after a successful "Full Sync" everything is > OK and all reponse times are normal! > > BUT after a disconnection and a new connect, drbd makes correctly a > "QuickSync", the response times when Connected now follows the "-t 20" > parameter value above. > Changing this parameter I can change the respone time accordingly. > > The slower machine is always Primary when the problem occurs. > > With the help of tcpdump and some trace printouts inside drbd my > understanding of drbd behavior look like this: > > Connection phase looks Ok, same as after "FullSync". > > Then after each data transfer from Primary to Secondary, the Secondary > acknowledged at TCP level Ok but the "DRBD Data Acknowledge" is > missing. > > After "-t 20" (2 seconds) Primary got response timeout and sends a > DRBD_Ping, to try the connection, which Secondary immediately > acknowledged and immediately after this the Secondary also sends the > missing "DRBD Data Acknowledge". > > When Primary receives "DRBD Data Acknowledge" it sends next Data > block, waits for response 2 seconds, times out and sends DRBD_Ping > "und so weiter".......... Result is a 2 seconds delay for every disk > access.. > > Have anyone seen this situation and perhaps even know how to solve it. > I would be very grateful for any kind of help and information. since you seem well able to use printk and tcpdump, please have a look whether the "WriteHint" packets are actually sent and received. if not, I probably know a solution (patchlet). -- : Lars Ellenberg Tel +43-1-8178292-0 : : LINBIT Information Technologies GmbH Fax +43-1-8178292-82 : : Schoenbrunner Str. 244, A-1120 Vienna/Europe http://www.linbit.com : __ please use the "List-Reply" function of your email client.