On Fri, 19 Mar 1999 14:55:46 EST, Paul Taylor wrote:
I am installing quad fast ethernet cards in my F330 and F630 filers.
- What version of ON-TAP should the filers be running?
- What configurations issues should I be aware of, and how are multipule default gateways configured?
Assuming that you are running a quad card so that you can touch four different subnets...
We ran with a quad card in our F520 with 4.something (I forget now, we're currently at 5.2.1) for a year w/o any problems with that.
You only have one "default gateway". Let's see if I can sum up why without oversimplifying:
The kernel maintains a list ("routing table") of 'what goes where' when a packet has to go out. It would be prohibitively expensive memorywise to know the exact path ("route") that each packet had to take for each arbitary machine in your machine's IP world (usually the internet so that your autosupport mail makes it to netapp.com).
To simplify things (and allow failover routing to function), the routing table only keeps a list of immediate networks and destinations (and hand-entered routes), and one place to send "everything else" that it doesn't know directly.
This is the "default gateway".
ok, sorry for the "TCP/IP Networking 101" class, but I thought it would help.
With that in mind, things are very simple. If you already have a "default gateway" set up because of your single card, you probably don't have to change it. Just assign ip addresses for each of the ports on the quad card that you're going to use, wire them up, and boot (OS rev issues aside).
fwiw, we tried to 'load balance' two ports by giving them different ip addresses on the same subnet and letting solaris automounter on each of the client boxes "choose the shortest path". It didn't work out as well as we had hoped, we're not hitting near 25% capacity on either of the two ports (mmm, mrtg).
-- Rob ---------------------------------------- Rob Windsor E-Mail - mailto:windsor@adc.com Senior Unix Systems Administrator Voice - phone:972-680-6919 Computer Services Fax - phone:972-680-0370 Business Broadband Group ADC Telecommunications Richardson, TX 75082
On Fri, 19 Mar 1999, Rob Windsor wrote:
Assuming that you are running a quad card so that you can touch four different subnets...
or to be more exact to touch more than one subnet.
You only have one "default gateway". Let's see if I can sum up why without oversimplifying:
Actually you have at most 1 default gateway.
To simplify things (and allow failover routing to function), the routing table only keeps a list of immediate networks and destinations (and hand-entered routes), and one place to send "everything else" that it doesn't know directly.
But it doesn't have to have a place to send "everything else." In fact if you have at least interface directly attached to every network you want the NAC to service and don't want people to be able to access it from anywhere else, you don't want to set a default gateway. Also, if you put in statically all the gateways for all the networks you want the NAC to service and don't want it to service any other network then you also don't want to have a default gateway.
With that in mind, things are very simple. If you already have a "default gateway" set up because of your single card, you probably don't have to change it.
Unless you don't want the traffic to go through that gateway anymore.
It didn't work out as well as we had hoped, we're not hitting near 25% capacity on either of the two ports (mmm, mrtg).
I don't understand, you should be happy about the network not being congested. BTW, that's a clever poor man's trunking (or really LAN aggregation). ;)
Tom
1999-03-19-23:05:48 Rob Windsor:
You only have one "default gateway".
That statement may well be true for e.g. NetApps running some particular version of OnTap, and I know it's true for SunOS 4.x, but it is not a universal truth; in particular, you can usefully have multiple default gateways under Solaris 2; I believe it round-robins packets among them.
At a previous job, we had a truly sexy network set up. Had a pair of sweaty, steaming 7513s or thereabouts as the core routers for the main office; all the main nets in that office were all served by both routers, backing each other up in HSRP config. More precisely, there were two HSRP groups, one that used one router as primary and one with the other router primary. For SunOS, we spread the hosts out by hand; they'd use one or the other of the HSRP groups according to the last quad of their IP addr was even or odd. For Solaris 2 we could just list both ip addresses, for both HSRP groups, in /etc/defaultrouter and the clients would spread themselves over the two groups.
We still tried to avoid having to route packets; where we could, we tried to place the server and the clients on the same subnet, preferably on the same switch (to avoid an ISL hop). But we could soak up one heck of a lot of traffic pouring between nets:-).
Those 7513s were fun. I remember when we got 'em in, we needed to unplug our Cray to free up some amps on the UPS. Turns out a pair of fairly-well-populated 7513s do nearly as good a job of turning kilowatts into BTUs as a Cray Y/MP.
Back on the topic of multiple default routes, I'm not convinced that the advantages are worth any complexity to implement; it was pretty minor. But if it isn't hard to implement, it's kind of nice, in much the same way a round-robin Etherchannel load spreader would be nicer than a hashed-macs one; it lets a single host spread its traffic, which means that neither router normally sees as nasty of bursts.
-Bennett
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Bennett Todd -
Rob Windsor -
tkaczma＠gryf.net