On Thu, 2009-12-10 at 16:58 +0100, Florian Haas wrote: > Lars beat me to this but anyway... > > On 2009-12-10 13:23, Beck Ingmar wrote: > > > > Hi Florian, > > > > why improves bonding of the replication-connection not the performance. > > I did not say that. :) I said round-robin bonding _over 4 NICs_ would be > detrimental to performance. > > > We currently have a direct connection for the 1 Gb DRBD replication and > > I > > wanted to activate an active-active bonding (with a further LAN-port). I > > would expect nearly double of replication-performance. > > All of the following applies to DRBD Connected in protocol C: > > - With 1 GBit Ethernet link, you can do about 110 MB/s (provided your > storage subsystem has that bandwidth); > > - With 2 GBit links bonded in round-robin mode, you top out at around > 160-170 MB/s (even then you may have to tune kernel TCP parameters); > > - with 3 Gbit links, your throughput will drop down to around 110 MB/s; > > - with 4 links or more, you will get _significantly less_ throughput > than a single unbonded link. > > Reason for all this: TCP reordering. > > > Or depends it on whether the connection between the nodes directly or > > via 1-n switches. > > I am talking about back-to-back connections. Switches could make it worse. >
Do Jumbo Frames make any difference here? Mark. -- Mark Watts BSc RHCE MBCS Senior Systems Engineer, Managed Services Manpower www.QinetiQ.com QinetiQ - Delivering customer-focused solutions GPG Key: http://www.linux-corner.info/mwatts.gpg
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