From: marmen@bcara347.bnr.ca (Rob Marmen 1532773)
Subject: Re: NIS - Problems on what systems?
Summary: One Nasty Prob
Organization: Bell-Northern Research, Ottawa, Canada
Distribution: usa
Date: Mon, 25 Jan 1993 14:51:38 GMT

In article <947@wavefront.wti.com>, kate@wavefront.wti.com (Kathy Samec) writes:
> What sorts of problems have any of you seen with a heterogeneous network
> and Different YP(NIS) servers? Is it really all it's hyped up to be?
> 

We have a mix of HPs, Suns and IBMs, and have several NIS domains. The
largest domain services about 4000 machines and has about 80 servers.

The biggest problem that I have is the inefficiency of the getpw* and
getgr* routines by all the vendors. We setup accounts as individual
'+' entries in the passwd file. Consequently, a getpwuid call will
generate a NIS request for each entry in the passwd file. This causes
slowdowns for the user. In some cases, telnets can timeout before a
user complete the login process.

The vendors position is that the software is working as designed, and
they don't see any reason to change.

Here is the output of a network trace showing the usage on a
particular subnet. The traffic was logged around 10 AM. The duration
was three minutes.

   4804 NFS
   2345 YP
   1351 XWIN
   1169 UDP
    538 RSTAT
    345 TCP
    161 RLOGIN
    122 ARP
     81 DLC,
     40 ATP
     35 RPC
     30 RIP
     19 SNMP
     14 PMAP
     12 MOUNT
      9 RTMP
      6 Telnet
      4 Ethertype=8005
      4 DSAP=FC,
      3 Ethertype=8019
      2 ECHO
      1 BOOTP
------------------
   11,095 Total

Please note that about 21 percent of all lan traffic is just NIS/YP
traffic.

If we further breakdown the NIS traffic by type, then we get the
following distribution.

     1172 OK                        (replies from the yp slave)
      912 bnrottawa.passwd.byname   (direct key lookups)
      234 bnrottawa.services.byname (getservbyname call ) see note
       11 bnrottawa.netgroup.byhost (direct key lookups)
       10 bnrottawa.hosts.byname    (direct key lookups)
        4 bnrottawa.hosts.byaddr    (direct key lookups)
        1 service                   (domain request)
        1 nothing                   (do nothing)
-------------------------------
     2345 Total

note: Suns do sequential searches of the services.byname map. This is
      replaced by a single lookup on HPs. The spike in
      services.byname traffic is due to the Sun workstations.

From the table, 78 percent of all NIS requests were for a single key
lookup from the passwd map. If 21 percent of all packets were NIS
related, then passwd specific lookups make up for around 16 percent
of the total number of packets in the snapshot.

This is surprising since we always suspected that the services.byname
traffic was responsible for the majority of the lan traffic.

NIS would be more efficient if the routines were rewritten to minimize
network traffic.

Hope that this helps.

Rob...

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| Robert Marmen             marmen@bnr.ca  OR             |
| Bell Northern Research    marmen%bnr.ca@cunyvm.cuny.edu |
| (613) 763-8244         My opinions are my own, not BNRs |
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