✓ Thêm một lệ phí hàng năm là 20% để bảo trì và hỗ trợ. ✓ Xem xét CNTT chi phí (bao gồm cả các dịch vụ hỗ trợ và phần cứng kiểm soát truy cập: Xác định những người hoặc những gì có thể truy cập những gì, và khi nào và làm thế nào họ có thể truy cập nó. ACID: | 242 Part IV Managing the Cloud IT and the service provider must work together to establish these SLAs. Typical SLAs include the following Response times possibly varying by transaction Availability on any given day Overall uptime target Agreed-on response times and procedures in the event a service goes down The agreement theoretically gives you some assurance that the provider will meet certain service levels. But buyer beware You need to determine the following Downtime Depending on how critical your applications running in a cloud are you will need a certain level of availability. Is percent enough for you Or do you require five nines How does the provider plan to ensure that it will meet its SLA What failover and disaster recovery mechanisms does the provider have in place Are you comfortable with them You need to read the fine print. Does the SLA include planned maintenance or is that separate If so how does planned maintenance affect you How the lines of responsibility are drawn You don t want to be in a situation where the SaaS provider is pointing a finger at the infrastructure provider saying it wasn t their fault. Cost of downtime What does it mean to your operations if the cloud is down Service providers might compensate simply based on the number of hours systems are down. What about the cost to your business Past incidents Has your provider struggled with excessive downtime in the past Check the record. Also look at service desk metrics including Time to identify problem Did a problem exist for a long time before it was reported Is performance varying widely without warning If this is true it means that the monitoring system isn t performing well and should be reviewed. Time to diagnose Time between an event report and the identification of the cause of the problem. Time to fix Time between diagnosis and system repair or resumption of service. Ideally you can see the operations of your service provider. The SLA .
