Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
-----Original Message----- From: Hans Holm [mailto:hans at vivdata.se] Sent: den 18 augusti 2005 20:56 To: Hans Holm Subject: Fw: [DRBD-user] DRBD (0.6) slows down the application ----- Original Message ----- From: "Lars Ellenberg" <Lars.Ellenberg at linbit.com> To: <drbd-user at lists.linbit.com> Sent: Thursday, August 18, 2005 10:40 AM Subject: Re: [DRBD-user] DRBD (0.6) slows down the application > / 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). The "WriteHint" packets are sent and received. I attached extracted info from /var/log/messages and tcpdump if it is of any help. /Hans > > -- > : 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. > _______________________________________________ > drbd-user mailing list > drbd-user at lists.linbit.com > http://lists.linbit.com/mailman/listinfo/drbd-user > -------------- next part -------------- An embedded and charset-unspecified text was scrubbed... Name: drbdProb.txt URL: <http://lists.linbit.com/pipermail/drbd-user/attachments/20050819/46e96a2c/attachment.txt>