Serial over LAN

Tim Small tim at seoss.co.uk
Fri May 21 04:29:36 CDT 2010


Case van Rij wrote:
> I have this configured on 45 R410s with iDRAC Express and have tried
> it in the past on 50 R210s and a handful of 1950s and I have to say,
> even once configured it's actually rather frustrating to use and it's
> no substitute for a cyclades-like serial console server.
>
> I initially tried to use this with the ethernet port on my regular
> switch (even though the ethernet port was dedicated to PXE and IPMI,
> all normal traffic is using an add-on 10G card) and the management
> port would simply stop responding to network traffic on a daily basis.
> I've since moved the ethernet to an isolated switch and it's
> marginally better, but the serial-over-LAN is still so unresponsive
> that remote management automation frequently times out while trying to
> manage the server).
>   

I've found performance on R210s to be good.  1950s and PE860s less so.
I've found reliability pretty good using recent ipmitool builds.  Here's
how I have an R210 set up (I think these were just the defaults).

# ipmitool sol info 1
....
Character Accumulate Level (ms) : 50
Character Send Threshold        : 255
Retry Count                     : 7
Retry Interval (ms)             : 480
Volatile Bit Rate (kbps)        : 115.2
Non-Volatile Bit Rate (kbps)    : 115.2
Payload Channel                 : 1 (0x01)
Payload Port                    : 623

You may want to try:

1. Using a recent ipmitool, if you're not already.
2. Fiddling with the first 4 values.  I'm guessing that things like the
"retry interval" could come down on a LAN - half a second to retry a
dropped packet seems like a long time at first consideration....  It
would perhaps have been nice if IPMI did stuff over TCP rather than UDP,
but when it was defined it didn't to SoL, so I suppose UDP was good
enough, and nice and light-weight for doing other (non-interactive) IPMI
comms.

HTH,

Cheers,

Tim.


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