[FASherman]

This is just my personal opinion, but I think it is far more advantagous to let AIX deal with network adapters than having HACMP manage adapter failover.

Etherchannel, an AIX 5L based-feature, allows several Ethernet adapters to be grouped together to form a single pseudo Ethernet device and thus provides increased network bandwidth availability, and redundancy.

Etherchannel devices can be configured as a contatinated device, meaning that en4 has the aggregate bandwidth of en0, en1, en2 and en3.

Etherchannel devices can also be configured ina primary/backup configuration. Using the above example, en4 could be configured as the aggregate of en0 and en1 with en2 annd en3 as backup adapters if any of the primaries fail.

Etherchannel devices give us better control and better failure response time than allowing HACMP to provide network redundancy. I, for one, will configure all future HACMP deployments using etherchannel devices as the network redundancy method and us HACMP for storage resources and application management only.

Its getting to the point where a properly designed HA solution will have HACMp doing as little as possible and I am just fine with that approach.

[steevojb]

Here Here

I have recently opted for etherchannel against HACMP for network

One question though. I only configured a service label on top of the label configured during the AIX build. Do you envisage any problems with this ? What is the need for a persistent label in this configuration ?

TIA

Steve

[FASherman]

The benefit of a persistant IP is that you always have a way into that server, regardless of the resource state.

Its been my experience that users who are new to HACMP or HA in general, have a tough time mentally separating the service IP from the primary server. They tend to give the service IP the same name as the host name. I like to avoid that.

I make the persistant IP match the host name and the service IP match the resource or application name.

The early days of HACMP is partly responsible for this. It used to be if you had a host name, you had a boot address of something like hostname_boot and a service address of hostname.

Now if I have an LPAR named sbti04, I make the persistant address sbti04. The service address associated with an Oracle database will be something like sbti_ora1.

If I need to perform maintenance on sbti04, I know what address to use, regardless of where the Oracle DB is located. If I need to work with the database, I have an address mentally tied to it that allows me to find the database, regardless of which server its on.

I think it makes more sense that way.

Did I answer your question or did I start to ramble?

[steevojb]

Hi there

Not at all.

I was confused by the fact that I have configured TCP/IP on the server and created my hostname with it's IP address. I have then created a service address for oracle. But in HACMP I also have an option to create a persistent address, which in my mind I already have (or are they the same thing ?)


Steve

[FASherman]

In that case, your hostname address is the persistant address, but since you're managing adapter failover via etherchannel, HACMP doesn't need to do a thing. You're good.

[bcarlson]

For those, like myself, who discarded the etherchannel approach based on the label Etherchannel (as in Cisco Etherchannel), take a second look.

Part of the AIX etherchannel functionality is Network Interface Backup. If one sets up a single interface etherchannel and assigns a NIB, no Etherchannel support is necessary at the switch. Simple redundancy without the complication of HACMP.

[Dharani]

Hi Steve,

Persistent IP nothing but alaias it's main puspose using persistent IP Adminisration use.

Please feel free if u have any doubt send reply me.

Bye and take care

Dharani

Originally Posted by steevojb

Here Here

I have recently opted for etherchannel against HACMP for network

One question though. I only configured a service label on top of the label configured during the AIX build. Do you envisage any problems with this ? What is the need for a persistent label in this configuration ?

TIA

Steve

[HelloNair]

A confusion here..

When you say etherchannel... Does it mean the etherchannel configruation on the switch end? or etherchannel failover configuraiton on AIX ?

The etherchannel failover on AIX helps where there is a physical adapter failure or when the network connection to one of the adapter fails.

HACMP does the same, but etherchannel failover is more simple and manageable.