On 01/02/14 08:47 AM, Dan Barker wrote:
-----Original Message-----
From: [email protected] [mailto:drbd-user-
[email protected]] On Behalf Of Harka Gyozo SA
Sent: Saturday, February 01, 2014 1:32 AM
To: [email protected]
Subject: [DRBD-user] drbd not working with high mtu?
Hi!
Anyone knows about an issue with mtu?
I tried to increase it to max ( there are two nics with a crossover cable,
so
no switch, router etc.. ). I found that max mtu supported by my card's
driver
is 7200.
ssh, ping (also with big packages), nfs works.
drbd keeps saying:] block drbd1: [drbd1_worker/16675] sock_sendmsg time
expired, ko = ...
If I decrease the mtu to 6000, error message stops, and I can see the
syncing
in the /proc/drbd (While the mtu is high it's stalled).
If I increase the mtu to 6200, kernel message returns, communication
stalled.
This is a bug? Or maybe I should increase buffer sizes in the config?
[ version: 8.3.7 (api:88/proto:86-91) ]
HARKA Győző
-----------
ssh, ping, nfs all will fragment packets.
Try ping with a 10K size and the don't fragment switch set. Lower the size
until it works.
ping -M do -s 6800 -c 1 <host>
Dan
Exactly what I was going to say. Remember though to set the ping payload
to 28 bytes less than the MTU you set to allow space for the ICMP
overhead. So if you set 7200 (sounds like a realtek...), use '-s 7172', etc.
--
Digimer
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