[j-nsp] (M7i RE5.0) memory usage

[Richard A Steenbergen]

On Sun, Mar 28, 2010 at 11:14:51AM +0200, Alfred Schweder wrote:
> So I see in "task memory" was is going on inside the rpd and with
> "sysem proc sum" I see the system over all ?

Correct.

> Im wondering, where I waste memory, cause there are many posts which
> state that 512MB would be fine for 4 full tables. Ive only three and
> the 768MB are full. 

There is a big difference between paths and routes. When people say "4
full tables", they usually mean 4 full table FEEDS going into a single
table. This results in 310k routes, and 310k * 4 paths, which consumes a
lot less memory than if there were really 1240k routes. Based on the 
results below it looks like yo may have some independent routing 
configurations going on (4 seperate rpd processes at any rate), which is 
going to incur a lot of extra overhead.

But if you strictly look at what memory is absolutely needed to
function, you're doing pretty well (especially if that is 4 full feeds
in that main rpd process). The amount of memory in "wired" (basically,
being used by the kernel or mlocked) is a little excessive, that's
probably attributable to feature bloat on modern code more than anything
else. You might be a lot better off running some older code if you're 
going to keep trying to run the old RE too. :)

> Are there are some knobs to reduce the memory consumption like not to use
> "softreconfiguration" at cisco boxes ?

Yes, you can configure "keep none" under protocols bgp (or group or
neighbor levels) to do sortof the same thing. It doesn't completely 
eliminate the adj rib in (which is a good thing), it just doesn't retain 
a copy of any route you explicitly reject in your policies. I don't 
think this is going to be a huge savings for you unless you are 
receiving and rejecting a lot of routes, and FYI it will flap your bgp 
sessions when you configure it.

> last pid: 37745;  load averages:  0.01,  0.06,  0.07
> 68 processes:  1 running, 67 sleeping
> CPU states: 16.3% user,  2.4% nice,  6.0% system,  0.8% interrupt, 74.5% idle
> Mem: 509M Active, 56M Inact, 148M Wired, 24M Cache, 69M Buf, 4412K Free
> Swap: 1536M Total, 118M Used, 1418M Free, 7% Inuse
> 
>   PID USERNAME  THR PRI NICE   SIZE    RES STATE    TIME   WCPU COMMAND
>  1219 root        1   4    0   408M   389M kqread 653:16  1.56% rpd
>  1222 root        1 111   15 43100K 40116K select  12:52  0.59% sampled

If you aren't using netflow, you can disable your sampled process which
is sucking down a decent amount of ram. The problem is that the routing 
table data is copied from rpd to sampled just so you can populate the 
"asn" field of netflow, and there is no way to disable this behavior if 
you don't care about that field. Unfortunately the only solution is to 
kill sampled completely, if you aren't using netflow of course.

I'm not sure if it will automatically disable things if you don't have 
sampling configured, but you can forcably disable things by configuring 
"system processes sampling disable".

>  5188 root        1  96    0 34420K 13016K select   1:40  0.00% mgd
>  5187 alf         1   8    0 15264K  9760K wait     5:00  0.00% cli
> 13189 root        1   4    0 29680K  8980K kqread  10:45  0.00% rpd
> 16931 root        1   4    0 29680K  8964K kqread   6:56  0.00% rpd
>  1212 root        1   4    0 29444K  7848K kqread  10:29  0.00% rpd
>  1235 root        1  96    0 22408K  7056K select 104:56  0.29% snmpd
>  1234 root        1  96    0 14836K  6352K select  33:56  0.00% mib2d
>  1174 root        1  96    0 43204K  6300K select  39.2H  1.17% chassisd
>  6007 bg          1  96    0 15188K  4800K select   0:52  0.00% cli
>  1821 alf         1  96    0 15200K  4684K select   0:52  0.00% cli
>  1342 alf         1  96    0 15188K  4584K select   0:55  0.00% cli

4.5MB+ for each of those cli processes is probably going to add up too, 
but realistically there are a lot of pages you just don't need in real 
time, and the vm system is doing the right thing by swapping them out. 
You can probably run "just fine" with a decent amount of memory used in 
swap.

-- 
Richard A Steenbergen <ras at e-gerbil.net>       http://www.e-gerbil.net/ras
GPG Key ID: 0xF8B12CBC (7535 7F59 8204 ED1F CC1C 53AF 4C41 5ECA F8B1 2CBC)