Old problem still present on 11-ALPHA1 - Pi2

[Karl Denninger]

I have two PI2s on the same switch here doing quite-different things.

One never shows network problems.  The other one does this:

....

ukphy0:  none, 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
ue0: <USB Ethernet> on smsc0
ue0: Ethernet address: b8:27:eb:08:12:1c
ugen0.4: <Inateck> at usbus0
umass0: <Inateck product 0x5136, class 0/0, rev 2.10/0.01, addr 4> on usbus0
umass0:  SCSI over Bulk-Only; quirks = 0x0100
umass0:0:0: Attached to scbus0
da0 at umass-sim0 bus 0 scbus0 target 0 lun 0
da0: <Inateck  0> Fixed Direct Access SPC-4 SCSI device
da0: Serial Number 00000000000000000000
da0: 40.000MB/s transfers
da0: 476940MB (976773168 512 byte sectors)
da0: quirks=0x2<NO_6_BYTE>
random: unblocking device.
smsc0: chip 0xec00, rev. 0002
ue0: link state changed to DOWN
ue0: link state changed to UP
ue0.2: link state changed to UP
ue0.3: link state changed to UP
ue0: link state changed to DOWN
ue0.2: link state changed to DOWN
ue0.3: link state changed to DOWN
ue0: link state changed to UP
ue0.2: link state changed to UP
ue0.3: link state changed to UP
ue0: link state changed to DOWN
ue0.2: link state changed to DOWN
ue0.3: link state changed to DOWN
ue0: link state changed to UP
ue0.2: link state changed to UP
ue0.3: link state changed to UP
ue0: link state changed to DOWN
ue0.2: link state changed to DOWN
ue0.3: link state changed to DOWN
ue0: link state changed to UP
ue0.2: link state changed to UP
ue0.3: link state changed to UP

Every now and then (every hour or so) the interface flaps.  If I plug a
USB interface in and use two network cords I *still* get the flapping. 
This unit has very low (but non-zero) traffic on the network, while the
other actually has *more* traffic on the network yet is completely
stable.  Since both are plugged into the same physical switch I doubt
the switch itself or its firmware is involved in this.

The only difference I can see is that the one that flaps is using
vlans.  Specifically, that machine is the network's dhcp server, and it
is on three different vlans (untagged and two tagged) so it can provide
addresses (and DNS services via unbound) to those VLAN interfaces.

This appears to be somehow linked to the ue interface driver, because
another machine (Intel based) that is also on multiple vLANs via the em
driver does *not* flap.

I don't know if this is actually arm related or not; it might not be if
Intel machines also use the "ue" driver, but it's very consistent on the
PI2 if I want to use vlan tags whether I have one or two interfaces (the
second via a USB adapter of course) in use or not.

Other than the flapping the box appears to run fine; the flaps do,
however, sometimes stop reporting from the snmpd daemon so I have had to
stick a cron job out there to restart that on a schedule to prevent it
from interrupting reporting to my traffic management tools.  Whether the
two are related is not known with certainty (but I suspect it is.)

-- 
Karl Denninger
karl at denninger.net <mailto:karl at denninger.net>
/The Market Ticker/
/[S/MIME encrypted email preferred]/
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