Can we install multiple mid servers on same host or VM

[Asmita7]

Hi friends,

I have a few doubts.

1. Can we install multiple mid servers on same host or VM pointing to same ServiceNow instance ? --- I think this is not best practice

2. Can we install multiple mid servers on same host or VM pointing to different ServiceNow instance ? We want to use these 2 mid servers as a cluster.

3. If we are creating cluster of mid server, then shall we go with Load balancer or Fail over mid server option ?

Your efforts will be appreciated.

Thank you,

Asmi

[Ankur Bawiskar · Accepted solution]

@Asmita7 

responses inline

1. Can we install multiple mid servers on same host or VM pointing to same ServiceNow instance ? --- I think this is not best practice - yes possible but not recommended

2. Can we install multiple mid servers on same host or VM pointing to different ServiceNow instance ? We want to use these 2 mid servers as a cluster. - yes, possible

3. If we are creating cluster of mid server, then shall we go with Load balancer or Fail over mid server option ? - depends on your customer's requirement and for what purpose mid server is being used

Install multiple MID Servers on a single system 

If my response helped please mark it correct and close the thread so that it benefits future readers.

[Ankur Bawiskar · Accepted solution]

@Asmita7 

responses inline

1. Can we install multiple mid servers on same host or VM pointing to same ServiceNow instance ? --- I think this is not best practice - yes possible but not recommended

2. Can we install multiple mid servers on same host or VM pointing to different ServiceNow instance ? We want to use these 2 mid servers as a cluster. - yes, possible

3. If we are creating cluster of mid server, then shall we go with Load balancer or Fail over mid server option ? - depends on your customer's requirement and for what purpose mid server is being used

Install multiple MID Servers on a single system 

If my response helped please mark it correct and close the thread so that it benefits future readers.

[DaveHertel · Accepted solution]

Hello - I offer below architectural advice I share with LOTS of clients.  In my example, I use 3 envs (Prod,Test,Dev) but the same works for however many envs you may have..

1. Can we install multiple mid servers on same host or VM pointing to same ServiceNow instance ? 
 Answer:  Absolutely.  If Host has sufficient resources (memory, CPU, etc.) and there are advantages to doing so for Discovery.   While some clients don't want their "prod" MID servers shared on a host that is also used by sub-env's, it works fine to have several, properly designed mid installs on a single host.   Example:  Hostname X with 3 mids (1 points to Prod, 1 toTest, 1 to Dev).

Advantages: Same IP for all 3... so if network has IP router/firewall/restrictions based on MID IP, network team sets 1 IP rule that applies to all 3 envs because all 3 MIDS originate from same host.

2. Can we install multiple mid servers on same host or VM pointing to different ServiceNow instance ? We want to use these 2 mid servers as a cluster.  

 Answer: Yes.  Same as above.  1 Host can have multiple MID installs, pointing to different SN instances

3. If we are creating cluster of mid server, then shall we go with Load balancer or Fail over mid server option ?

Answer:  Always go with Load Balanced type MIDS.   Fail over MIDS are worthless in my opinion.  Why?  Because 1) Load Balanced MIDS effectively do "fail over" automatically for horizontal discovery.. i.e. if 1 mid in a 2 mid LB cluster goes down, the other mid picks up all the work  naturally, which is same effect as a FO cluster

2) a Fail over cluster is a waste of resource.  99.9% of mids in a FO cluster do nothing because the 1st MID is always doing the work, while secondary mid is idle.  Conversely, in a LB cluster, both are sharing discovery functions distributing work naturally. 

I've done a lot of MID & Disco installs for clients... I always use these "rules" and they've always worked well.

Hope this helps?

Dave