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

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We just reduced our paths from 5 M to 1.5 M but still see high memory usage
values. Does Junos reclaim memory without a reboot?



On Sun, Mar 28, 2010 at 5:39 PM, Richard A Steenbergen <ras at e-gerbil.net>wrote:

> 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)
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