TLDR;
This video explains how to calculate storage size, focusing on response time, I/O operations per second (IOPS), and service time. It details the components affecting response time, including I/O delay and service time, and provides formulas for calculating IOPS and determining the number of disks needed based on application requirements. The video also touches on optimizing disk writing processes by minimizing head movements to improve performance.
- Response time is critical and affected by I/O delay and service time.
- IOPS (Input/Output Operations Per Second) is a key metric for disk performance.
- Disk optimization involves minimizing head movements for faster write operations.
Introduction to Response Time [0:00]
The video begins by discussing response time, which is affected when a system's score exceeds 70%. High response times can cause problems. The discussion covers how to calculate response times and the rules involved. Response time is divided into I/O delay and service time. Exceeding 70% impacts response time negatively. Service time is further divided into sick time.
Calculating Storage Size [2:31]
The video addresses how to determine hard disk size, considering the number of commands per minute relative to RAM usage. It emphasizes the importance of calculating values based on specific rules and parameters. The video uses the term "Ayus" which means Input/Output Operations Per Second (IOPS).
Understanding IOPS (Input/Output Operations Per Second) [4:45]
The video explains IOPS, which measures how many read/write operations a disk can handle per second. If an application needs to write 20MB per second but the disk only supports 10MB per second, it creates a bottleneck. The application determines the required IOPS. The formula to calculate IOPS involves dividing the total IOPS needed by the IOPS provided by one disk to determine the number of disks required.
Calculating Disk Requirements [8:36]
The video details how to calculate the number of disks needed based on IOPS. By knowing the IOPS a single disk can provide, one can divide the total IOPS requirement by the single disk IOPS to find the necessary number of disks. The final disk number is determined by taking the maximum value between the calculated disk number and the initial estimate.
Optimizing Disk Writing Process [11:01]
The video introduces Native Command Queuing (NCQ) as a method to optimize disk writing. Instead of writing data in a scattered manner across different tracks, NCQ organizes the writing process to minimize head movements. Writing sequentially on the same track reduces the time taken compared to jumping between tracks, improving overall performance.