[OpenAFS] rxmaxmtu for volserver
Ximeng Guan
xmgu@royole.com
Sat, 29 Sep 2018 22:43:52 +0000
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Hello,
We recently found that volume release and movement between file servers run=
ning at two different sites fail frequently because the path MTU between th=
e two sites is smaller than the default value of 1500.
The failure happens particularly between a file server running 1.6.21 and a=
file server running 1.6.22.3 on the other site. It does not seem to happen=
between two file servers both running 1.6.21 on the two ends.
Although setting the file server's NIC mtu (e.g., in the file ifcfg-eth0) t=
o the true path max MTU value seems to be an ad-hoc solution, we notice tha=
t the volserver has a new option of -rxmaxmtu in 1.8. The auristor version =
also has the same option in its documentation. But the 1.6.x version does n=
ot.
Is there a plan to introduce this option into 1.6.x? Can someone provide an=
y background or history on this option for the volume server?
Thank you!
P.S., when the failure happens, we typically see a symptom like this: Probi=
ng the sender with rxdebug at port 7005 shows an active connection to the r=
eceiver with a flag of "has_output_packets". Probing the receiver at the sa=
me port does not show the corresponding connection.
Best regards,
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
Ximeng (Simon) Guan, Ph.D.
Associate Principal Engineer
Royole Corporation
48025 Fremont Blvd, Fremont, CA 94538
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
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<p class=3D"MsoNormal"><span style=3D"font-size:12.0pt">Hello,<o:p></o:p></=
span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:12.0pt"><o:p> </o:p></=
span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:12.0pt">We recently found t=
hat volume release and movement between file servers running at two differe=
nt sites fail frequently because the path MTU between the two sites is smal=
ler than the default value of 1500.
<o:p></o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:12.0pt"><o:p> </o:p></=
span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:12.0pt">The failure happens=
particularly between a file server running 1.6.21 and a file server runnin=
g 1.6.22.3 on the other site. It does not seem to happen between two file s=
ervers both running 1.6.21 on the two
ends. <o:p></o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:12.0pt"><o:p> </o:p></=
span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:12.0pt">Although setting th=
e file server’s NIC mtu (e.g., in the file ifcfg-eth0) to the true pa=
th max MTU value seems to be an ad-hoc solution, we notice that the volserv=
er has a new option of -rxmaxmtu in 1.8. The
auristor version also has the same option in its documentation. But the 1.=
6.x version does not.
<o:p></o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:12.0pt"><o:p> </o:p></=
span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:12.0pt">Is there a plan to =
introduce this option into 1.6.x? Can someone provide any background or his=
tory on this option for the volume server?<o:p></o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:12.0pt"><o:p> </o:p></=
span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:12.0pt">Thank you!<o:p></o:=
p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:12.0pt"><o:p> </o:p></=
span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:12.0pt">P.S., when the fail=
ure happens, we typically see a symptom like this: Probing the sender with =
rxdebug at port 7005 shows an active connection to the receiver with a flag=
of “has_output_packets”. Probing the
receiver at the same port does not show the corresponding connection. <o:p=
></o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:12.0pt"><o:p> </o:p></=
span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:12.0pt;font-family:"Ti=
mes New Roman",serif">Best regards,<o:p></o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:12.0pt;font-family:"Ti=
mes New Roman",serif">=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D<o:=
p></o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:12.0pt;font-family:"Ti=
mes New Roman",serif">Ximeng (Simon) Guan, Ph.D.<o:p></o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:12.0pt;font-family:"Ti=
mes New Roman",serif">Associate Principal Engineer<o:p></o:p></span></=
p>
<p class=3D"MsoNormal"><span style=3D"font-size:12.0pt;font-family:"Ti=
mes New Roman",serif">Royole Corporation<o:p></o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:12.0pt;font-family:"Ti=
mes New Roman",serif">48025 Fremont Blvd, Fremont, CA 94538<o:p></o:p>=
</span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:12.0pt;font-family:"Ti=
mes New Roman",serif">=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
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p></o:p></span></p>
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