Less than...?? (Load Balancing - Priority Group Activation)

"Less than" literally means "less than." If I have 2 Priority Groups, each of which contains 2 pool members and I'm set to "Less than 1," my second priority group kicks in when I have exactly 0 pool members up. Make sense?

Hi Chris,

 

 

Thanks so much for your instruction so that I know the message's exact definition - literally same meaning.

 

But, I don't understand, so I'm now still confused.

 

 

I have uploaded the screen shot that the Web Based Training Quiz image by which I'm confused.

 

The file name is: Less_than_1_Avaliable_Members.JPG

 

In this image, Priority Group Activation is set to "Less than... 1 Available Member(s)".

 

I think this means no one available, since "Less than... 1".

 

 

And I also have uploaded the Answer screen shot named "Answer.JPG".

 

According to this, one member is available, different from my thought...

 

 

"Less than... 1 Available Member(s)" means that 1 member is availble?

 

"Less than... 1 Available Member(s)" means that no member is available?

 

Which is correct?

 

 

And, I see that the Configuration Guide could help me to solve this confusion, but I can not find the document in the F5 Website...Umm...

 

 

Thanks a lot,

 

Fumio

 

 

"Less than... 1 Available Member(s)" means that no member is available.

 

 

Example I've 4 member >> server 1,2 in priority group 1 ...3,4 in priority group 2 [I set Less than 1 available member]

 

 

At first when connect >> client can access only server 3,4

 

second I disable server 4 >> client still access only server 3

 

At last I disable server 3,4 >> client can access server 1,2

 

 

Thanks teepan123 and Chris,

 

 

It seems that we all are agree that "Less than..." means literally less than..., in other words, not less-than-or-equal-to,

 

so "Less than... 1 Available Member(s)" means that no member is available.

 

 

But my understanding regarding the BIG-IP behavior after this setting seems different from you.

 

I think, if no member is available, all members can not accept any connection, in other words, a client can not access to all members.

 

But it seems that my understanding is not correct, because it is different from Chris, teepan123 and Web-Based Training Answer.

 

 

I might be misunderstanding the concept of pool, pool members and load balancing.

 

I must and will study it again deeply, but your any more suggestions or hints are so helpful for me to quickly understand it.

 

 

Thanks so much for your instruction and I'm so sorry I still do not understand it.

 

 

Thanks,

 

Fumio

 

 

Fumio, I hope you have solved this by now,... but I just ran across the your question doing a search for something and thought it worth trying to explain for others who might find this thread. The piece you are missing is, that prioritization creates multiple groups of servers. So, the "less than 1" setting only applies to the ACTIVE prioritization group. Once the highest priority group has less than 1 UP member, the next priority group is in play,, and so on, through the list prioritization groups.

The setting does not apply to ALL pool members. Only the active prioirty group.

  Hope that helps!

  D

I think, if no member is available, all members can not accept any connection, in other words, a client can not access to all members.

 

i understand it is a number of active priority group member (i.e. not a number of active pool member).