Semaphore SHMMAX

What are the optimal values for  SHMMAX SHMMNI SHMALL ?

SHMMAX : Either SGA size of any individual database or half size of the system memory, whichever is the higher.

SHMMNI: Normally default value 4096 should be sufficient.

SHMALL: The sum of all the SGAs on the system, divided by the page size. The page size can be gotton by :

 $ getconf PAGE_SIZE
 4096

Scale IO, SSD or SDS

A large service provider recently signed a multi million-dollar deal with EMC SDS Solutions.  With this type of solution, the customer reduced its storage costs by 25%. This reference confirms the trend that customers are moving more and more towards Software Defined solutions, which aligns with the predictions from IDC, Gartner, Wikibon ....Here are some of my recaps and opinions on ScaleIO, based on what I’ve seen in the industry.

ScaleIO is one of the core Software Defined technologies at EMC. This innovative solution and the disruptive approach require a change in our traditional mindset. ScaleIO is not meant to replace all the workloads in the IT environments, but it’s key to accommodate Next-Gen applications.
 
ScaleIO’s principle is quite simple: a set of x86 servers is aggregated with local drives, which creates a virtual SAN. All the features of traditional storage arrays are preserved and offered at at a lower cost with a simplified management.

ScaleIO offers very high performance and high scalability while reducing management complexity and costs.

More detail Souce

https://community.emc.com/mobile/mobile-access.jspa#jive-document?content=%2Fapi%2Fcore%2Fv2%2Fposts%2F12715

Common waits event and causes

https://gavinsoorma.com/wp-content/uploads/2011/12/Resolving-common-Oracle-Wait-Events-using-the-Wait-Interface.htm

Mongo atlas

C:\Users\dilip\Desktop\Work\aws\mongoatlas\mongodb-win32-x86_64-2008plus-ssl-4.0.6\bin>mongo "mongodb+srv://mongogcp-horam.gcp.mongodb.net/test"     --username xxxxxxx -p xxxxx
MongoDB shell version v4.0.6
connecting to: mongodb://mongogcp-shard-00-00-horam.gcp.mongodb.net.:27017,mongogcp-shard-00-01-horam.gcp.mongodb.net.:27017,mongogcp-shard-00-02-horam.gcp.mongodb.net.:27017/test?authSource=admin&gssapiServiceName=mongodb&replicaSet=MongoGCP-shard-0&ssl=true
2019-03-27T00:03:06.406+0800 I NETWORK  [js] Starting new replica set monitor for MongoGCP-shard-0/mongogcp-shard-00-00-horam.gcp.mongodb.net.:27017,mongogcp-shard-00-01-horam.gcp.mongodb.net.:27017,mongogcp-shard-00-02-horam.gcp.mongodb.net.:27017
2019-03-27T00:03:06.570+0800 I NETWORK  [js] Successfully connected to mongogcp-shard-00-00-horam.gcp.mongodb.net.:27017 (1 connections now open to mongogcp-shard-00-00-horam.gcp.mongodb.net.:27017 with a 5 second timeout)
2019-03-27T00:03:06.571+0800 I NETWORK  [ReplicaSetMonitor-TaskExecutor] Successfully connected to mongogcp-shard-00-01-horam.gcp.mongodb.net.:27017 (1 connections now open to mongogcp-shard-00-01-horam.gcp.mongodb.net.:27017 with a 5 second timeout)
2019-03-27T00:03:06.700+0800 I NETWORK  [ReplicaSetMonitor-TaskExecutor] Successfully connected to mongogcp-shard-00-02-horam.gcp.mongodb.net.:27017 (1 connections now open to mongogcp-shard-00-02-horam.gcp.mongodb.net.:27017 with a 5 second timeout)
2019-03-27T00:03:06.707+0800 I NETWORK  [ReplicaSetMonitor-TaskExecutor] changing hosts to MongoGCP-shard-0/mongogcp-shard-00-00-horam.gcp.mongodb.net:27017,mongogcp-shard-00-01-horam.gcp.mongodb.net:27017,mongogcp-shard-00-02-horam.gcp.mongodb.net:27017 from MongoGCP-shard-0/mongogcp-shard-00-00-horam.gcp.mongodb.net.:27017,mongogcp-shard-00-01-horam.gcp.mongodb.net.:27017,mongogcp-shard-00-02-horam.gcp.mongodb.net.:27017
2019-03-27T00:03:06.737+0800 I NETWORK  [ReplicaSetMonitor-TaskExecutor] Successfully connected to mongogcp-shard-00-01-horam.gcp.mongodb.net:27017 (1 connections now open to mongogcp-shard-00-01-horam.gcp.mongodb.net:27017 with a 5 second timeout)
2019-03-27T00:03:06.782+0800 I NETWORK  [ReplicaSetMonitor-TaskExecutor] Successfully connected to mongogcp-shard-00-00-horam.gcp.mongodb.net:27017 (1 connections now open to mongogcp-shard-00-00-horam.gcp.mongodb.net:27017 with a 5 second timeout)
2019-03-27T00:03:06.830+0800 I NETWORK  [js] Successfully connected to mongogcp-shard-00-02-horam.gcp.mongodb.net:27017 (1 connections now open to mongogcp-shard-00-02-horam.gcp.mongodb.net:27017 with a 5 second timeout)
Implicit session: session { "id" : UUID("9148e5e2-51f1-4ea6-9a44-7d47ac3f6dbf") }
MongoDB server version: 4.0.6
MongoDB Enterprise MongoGCP-shard-0:PRIMARY>



C:\Users\dilip\Desktop\Work\aws\mongoatlas\mongodb-win32-x86_64-2008plus-ssl-4.0.6\bin>mongo "mongodb://mongogcp-shard-00-00-horam.gcp.mongodb.net:27017,mongogcp-shard-00-01-horam.gcp.mongodb.net:27017,mongogcp-shard-00-02-horam.gcp.mongodb.net:27017/test?replicaSet=MongoGCP-shard-0"  --authenticationDatabase admin --ssl -u xxxxxxxx -p xxxxxx
MongoDB shell version v4.0.6
connecting to: mongodb://mongogcp-shard-00-00-horam.gcp.mongodb.net:27017,mongogcp-shard-00-01-horam.gcp.mongodb.net:27017,mongogcp-shard-00-02-horam.gcp.mongodb.net:27017/test?authSource=admin&gssapiServiceName=mongodb&replicaSet=MongoGCP-shard-0
2019-03-27T00:00:16.228+0800 I NETWORK  [js] Starting new replica set monitor for MongoGCP-shard-0/mongogcp-shard-00-00-horam.gcp.mongodb.net:27017,mongogcp-shard-00-01-horam.gcp.mongodb.net:27017,mongogcp-shard-00-02-horam.gcp.mongodb.net:27017
2019-03-27T00:00:16.861+0800 I NETWORK  [ReplicaSetMonitor-TaskExecutor] Successfully connected to mongogcp-shard-00-02-horam.gcp.mongodb.net:27017 (1 connections now open to mongogcp-shard-00-02-horam.gcp.mongodb.net:27017 with a 5 second timeout)
2019-03-27T00:00:16.870+0800 I NETWORK  [js] Successfully connected to mongogcp-shard-00-00-horam.gcp.mongodb.net:27017 (1 connections now open to mongogcp-shard-00-00-horam.gcp.mongodb.net:27017 with a 5 second timeout)
2019-03-27T00:00:17.028+0800 I NETWORK  [ReplicaSetMonitor-TaskExecutor] Successfully connected to mongogcp-shard-00-01-horam.gcp.mongodb.net:27017 (1 connections now open to mongogcp-shard-00-01-horam.gcp.mongodb.net:27017 with a 5 second timeout)
Implicit session: session { "id" : UUID("24cf1e44-0cc7-4105-900e-5b90a6902a74") }
MongoDB server version: 4.0.6
MongoDB Enterprise MongoGCP-shard-0:PRIMARY>