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> On Thu, 9 Aug 2001 jsc3@xxxxxxxxxxxxx wrote:
>
> > OK, so if I want the HA features, then use on switch at a time. I
> > wonder if there is any way to have redundant (failover) bonded channels.
> > In other words, can I have a bonded channel (say, four ports - don't
> > put them all on one card by the way) on Catalyst 6500 A and another bonded
> > channel (another four ports) on Catalyst 6500 B, and then failover from
> > A to B should A go down? This is really not a Cisco question, but a
> > Linux question. I think the answer is probably no, but I was pleasantly
> > surprised yesterday, so I am going to be greedy and try again today.
>
> If you want HA, have one machine (machine A) with bonded channels
> connected to switch A, and have another machine (machine B) with bonded
> channels connected to switch B.
Well, yes, but usually a desirable goal is to reduce failover time
to a minimum, and avoiding complete failover as often as possible
is one means of doing this.
> If you want to go super-paranoid, and have money to burn on links that
> won't be used during normal operations:
For the scenario described above (two systems), in many cases machine
A is active and machine B is a passive failover, in which case you
have already burned some money on an entire system (with bonded
channels, no less) that won't be used during normal operations.
Considering I can get four (two for each system) SMC EtherPower
dual port cards for about $250, including shipping, or four Zynx
Netblaster quad cards for about $820, if I shop around carefully,
or $1000 for Intel Dual Port Server adapters or $1600 for Adaptec/Cogent
ANA-6944 quad cards, if a name brand is important), the cost seems less
significant when viewed in this light (not to mention the cost of two
Cisco switches that can do FEC too).
> have one machine (machine A) with
> bonded channels connected to switch A, and have backup bonded channels to
> switch B. Have software that detects failure of all bonded channels to
> switch A and fails over your IP to switch B (still on machine A). Have
> another machine (B), with two sets of bonded channels connected to switch
> C and switch D.
Or just have machine (B) connect to switches A and B, which is what I
see most often in actual process - but not with bonded channels.
> lather, rinse, repeat. On Solaris, IP failover to backup
> link is called IP Multipathing, IIRC. New feature of Solaris 8.
Yes, I believe I mentioned this earlier in the thread, actually.
I am quite familiar with it. I don't believe it does actual
bonding though, and does not require specific switch support.
It will do some very rudimentary load balancing of outbound
connections on a "per connection" basis, but does nothing for
inbound connections.
> Various HA
> softwares for Linux, notably Steeleye Lifekeeper and possibly
> LinuxFailsafe, support this as well.
I will have to look into these.
--
John Cronin
mailto: `echo NjsOc3@xxxxxxxxxxx | sed 's/[NOSPAM]//g'`
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