How does max client load settings work on primary and backup SVMs (no SVM manager)

[McDuff]

Greetings

This question relates to how the SVM Settings policy which configures the maximum number of clients works.

Our MOVE clients are configured to use a primary (SVMP) and backup (SVMB) SVM servers , no SVM Manager yet.  

If our policy is configured on both the primary and backup SVM servers to allow a max of 250 clients, would that mean that we could have a max of 500 clients, or a max of 250?  I originally thought the answer was 500, but an incident today has lead me to believe it's actually 250 since when I look at both SVMs, they both report an identical number of clients.

Further, assuming the max capacity is 250, is the max capacity reached:

1. When there are 250 active connections, or

2.  When 250 PCs (which may or may not be currently online) are configured to use these SVM server?   

[patrakshar · Accepted solution]

Hi @McDuff 

The answer will be 250 here.

Let me explain you in much detail here. 

The default number of connection (Heartbeat connection) that SVM can access. If you perform a mvadm stats at SVM side. You should see output like below:

C:\Windows\system32>mvadm stats
Total number of cksum req: 0
Total number of file transfer req: 0
Total number of smart file req: 0
Total number of scans on RAM disk: 0
Cksum cache hit: 0
Total av scan req: 0
Total av scan failure: 0
Data recv failure: 0
Resp send failure: 0
Total scan threads: 300
Total heart beat threads: 1
Total idle threads: 0
Number of requests in queue: 0
Number of items in cache: 0
Avg request process time (sec): 0.000000
Avg request wait time (sec): 0.000000

The above highlighted one "Total heart beat threads" tells you how many client connected to a particular SVM in any time. This number is max by default 250.

So if you have 2 SVM and one is Primary and another is secondary, then at any time only primary will take 250 connection and Secondary will stay idle. It is a fail-over system. Once Primary server goes down then all the 250 connections will back to secondary.

If your number of clients are more than 250, example 500 or so. Then you will need to create two group. Each group one primary and one secondary. That means for two group you will need 4 SVM. Each group will have 250 client assigned. 

Hope this helps. 

[McDuff]

Thank you very much, that really helps.