[j-nsp] J-2320 base configuration - gotchas

[Rubens Kuhl Jr.]

>> I'm sizing a J-2320, and noticed the following RAM and flash defaults:
>>
>> ? 256 MB DRAM default, expandable to 1 GB DRAM
>> ? 256 MB compact flash default, upgradeable to 1 G
>
> Juniper is nowadays shipping J2320-SC with 512M DRAM by default because
> of JUNOS 9.1 requiring more than the old 256M standard:
>
> http://www.juniper.net/techpubs/software/jseries/junos91/rn-jseries-91/j-series-compact-flash-and-memory-requirements.html#rn-cf-mem-reqs
>
> Interstingly, this table says max 2GB on J2320 - product "spec sheet"
> still says 256M by default, max 1GB.

Indeed... :-)

> Still, we're upgrading CF and DRAM to 1GB each to be ready for "full
> table" BGP, and able to have several JUNOS packages stored on the
> router. 256M flash was definately not comfortable (not even room for
> a single new JUNOS image file), and 256M DRAM even broke with just IPv6
> full table (~1000 routes). So for "very few routes" you should be
> somewhat ok with 512M DRAM and 512M flash, but we settle for 1G/1G as
> standard so we're fine for "any" application.

I intended to plan for 8k routes; we currently have less than 3k
routes, so that would leave room for growth and time to configure
filtering for a smaller view with just what is needed when it grows
beyond that point, which is also a hard limit on many hardware
forwarding platforms; Juniper's own EX-series goes up to 12k routes.



> BTW, J2320 has 4 DRAM slots and happily eats far more than just 1GB or
> even 2GB. We have one box in lab with 2.5G (1G+1G+256M+256M). Of course
> that's against product management's plans for J2320, so beware of losing
> JTAC support. :)

Memory addressing by the processor and the operating system, and the
network cards that do DMA might also have a saying about memory sizes,
the operating system being the most relevant part. That could explain
why JunOS 9.1 release notes state 2GB where the spec states 1GB.  It's
very likely that use memory beyond 2GB would need some rewriting of
the protected memory manager, may be backporting some code from newer
FreeBSD releases, no mather how much memory the system board can
handle.


Rubens