I'll be interested to hear how this works for you. THanks for the update. -Collin Dai, Manhong wrote: > > Hi Collin, > > Thanks a lot for your help. The interconnect is Gigabit Ethernet. > > I am guessing that it is caused by the router. Computing nodes that > connect to this router always retransmit 5% of segments under heavy > load. My test on other router has lower ratio, around 0.3%. I am about > to replace the router and perform another test. > > Anyway this problem is not related to glusterfs at all. Although I > do have another question that is about glusterfs, which I will send in > a separated email. > > Best, > Manhong > > Date: Mon, 25 Aug 2008 08:41:25 -0500 > From: Collin Douglas <cbd at adfitech.com> > Subject: Re: help, glusterfs test caused very high tcp > segment retransmission rate > Cc: gluster-users at gluster.org > Message-ID: <48B2B685.2050603 at adfitech.com> > Content-Type: text/plain; charset="ISO-8859-1" > > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA256 > > This sounds a lot like a physical layer issue -- most notably a > speed/duplex issue. Any time I've seen a large number of retransmits > occur during heavy load, this is what I suspect. > > That said, I don't know what type of interconnect you're using. Tell us > more about your configuration. > > - -Collin > > Dai, Manhong wrote: > > > > > > Hi, > > > > > > I found the aggregated IO speed is only about 100MB/s on 4 Giga-bit > > Brick. This test is done over 12 computing nodes with command dd > > if=/dev/zero of=bar bs=1048576 count=20480. Because our brick has very > > fast local IO speed, the problem could be network. > > > > > > Then I found computing nodes got too many retransmited segments > > during test according to netstat -st. The retransmission ratio is > > about 5%, but brick node has a normally low transmission rate. > > > > > > Could some shed some light? > > > > Best, > > Manhong > > ------------------------------------------------------------------------ > > _______________________________________________ > Gluster-users mailing list > Gluster-users at gluster.org > http://zresearch.com/cgi-bin/mailman/listinfo/gluster-users > -------------- next part -------------- An HTML attachment was scrubbed... URL: http://zresearch.com/pipermail/gluster-users/attachments/20080830/121a4170/attachment.htm -------------- next part -------------- A non-text attachment was scrubbed... Name: PGP.sig Type: application/pgp-signature Size: 476 bytes Desc: not available Url : http://zresearch.com/pipermail/gluster-users/attachments/20080830/121a4170/attachment.pgp
