[c-nsp] ASR-1001 bgp memory usage

[Arie Vayner (avayner)]

Christian,

You are most likely running in software redundancy mode, where the Linux
kernel takes a portion of the memory, and what is left is split 50/50
for 2 separate IOS processes.
You could disable software redundancy, and gain more memory for the
single IOS process.

Another option is to upgrade the RAM of the router. ASR1K can go up to
8G...

Some info about software redundancy can be found here:
http://www.cisco.com/en/US/docs/routers/asr1000/configuration/guide/chas
sis/Software_Packaging_Architecture.html#wpxref69339
http://www.cisco.com/en/US/docs/routers/asr1000/configuration/guide/chas
sis/High_Availability.html#wp1058945


Specifically for BGP, I would suggest you take a look at the output of
"show ip bgp summary". It shows how much memory BGP actually uses for
the different pieces of information.
This means that adding a new peer not necessarily means the same block
of memory is required for all the information, as network entries and
paths use separate links memory structures. If you get 2 full feeds,
most of the network entries would be the same, and there would just be
an addition path entry (which takes substantially less memory per entry
compared to a network entry).

This document may give you some further hints:
http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a008009
4a83.shtml


A common memory related optimization for BGP is to disable inbound soft
reconfiguration. This feature is not really needed today (due to dynamic
inbound soft reset), and takes a substantial amount of memory if you
take full routes with all the churn on the internet.
Here is some info about the feature:
http://www.cisco.com/en/US/docs/ios/11_3/np1/configuration/guide/1cbgp.h
tml#wp10995
http://www.cisco.com/en/US/products/ps6599/products_data_sheet09186a0080
087b3a.html


Hope this helps.
Arie

-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Christian
Kratzer
Sent: Wednesday, September 21, 2011 11:13
To: cisco-nsp
Subject: [c-nsp] ASR-1001 bgp memory usage

Hi,

we have a pair of ASR-1001 taking a full bgp feed ipv4 and ipv6 from our
upstream. We will have a second and third full feed soon and are quite a
bit surprised by the memory usage of the first full feed.

     Router-1#show memory
 		    Head    Total(b)     Used(b)     Free(b)   Lowest(b)
Largest(b)
     Processor  7FC5CB741010   1235972656   884561540   351411116
350518960   350730684
      lsmpi_io  7FC5CAEE61A8     6295128     6294212         916
916         916

I doubt we will fit a further 2 full feeds into that remaining 350 MB.

An old 2821 only used up 300 MB for one and a half full feeds. This box
seems quite thirsty.

The other router that is currently idle and not yet in the iBGP mesh
already has on offset of 380MB.

     Router-2#show memory
 		    Head    Total(b)     Used(b)     Free(b)   Lowest(b)
Largest(b)
     Processor  7FBD6A7E2010   1235972656   387423056   848549600
817362160   816870148
      lsmpi_io  7FBD69F871A8     6295128     6294212         916
916         916

show versions shows this beast has 4GB memory of which the IOS process
seems to use 1G

     Cisco IOS Software, IOS-XE Software
(X86_64_LINUX_IOSD-UNIVERSALK9-M), Version 15.1(1)S, RELEASE SOFTWARE
(fc1)
     Technical Support: http://www.cisco.com/techsupport
     Copyright (c) 1986-2010 by Cisco Systems, Inc.
     Compiled Mon 22-Nov-10 12:33 by mcpre

     cisco ASR1001 (1RU) processor with 1207124K/6147K bytes of memory.
     9 Gigabit Ethernet interfaces
     32768K bytes of non-volatile configuration memory.
     4194304K bytes of physical memory.
     7782399K bytes of eUSB flash at bootflash:.

I am currently not sure if I can assign the IOS process more memory
somewhere or how I could check how the available memory is distributed
to the subsystems or even if I have dual IOS processes running.

Any pointers ???

Greetings
Christian

-- 
Christian Kratzer                      CK Software GmbH
Email:   ck at cksoft.de                  Wildberger Weg 24/2
Phone:   +49 7032 893 997 - 0          D-71126 Gaeufelden
Fax:     +49 7032 893 997 - 9          HRB 245288, Amtsgericht Stuttgart
Web:     http://www.cksoft.de/         Geschaeftsfuehrer: Christian
Kratzer
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