How Many Resources Will Be Used for a Linux Block-Level Migration?
Memory Usage (of Data Cache)
There are six data cache nodes configured by the Agent on a source server. The default size of a single cache node is 4 MB.
- Minimum memory occupied by data cache: 6 x 1 MB = 6 MB
- Default memory occupied by data cache: 6 x 4 MB = 24 MB
- Maximum memory occupied by data cache: 6 x 8 MB = 48 MB
CPU Usage
The details about the CPU usage during a Linux block-level migration are as follows.
Number of CPUs | CPU Usage (%) Before the Agent Starts (n) | Default Compression Threads Configured by the Agent | CPU Usage After the Agent Starts |
|---|---|---|---|
1 | - | 0. Data compression is disabled by default. | < n + 10% |
2 | n ≥ 50% | 0. Data compression is disabled by default. | < n + 10% |
2 | n < 50% | 1 | < n + 50% |
4 | n ≥ 75% | 0. Data compression is disabled by default. | < n + 4% |
4 | 50% ≤ = n ≤ 75% | 1 | < n + 25% |
4 | 25% ≤ n < 50% | 2 | < n + 50% |
4 | n < 25% | 3 | < n + 75% |
8 | n ≥ 87% | 0. Data compression is disabled by default. | < n + 3% |
8 | 75% ≤ n < 87% | 1 | < n + 13% |
8 | 62% ≤ n < 75% | 2 | < n + 25% |
8 | n < 62% | 3 | < n + 38% |
16 | n ≥ 93% | 0. Data compression is disabled by default. | < n + 1% |
16 | 87% ≤ n < 93% | 1 | < n + 6% |
16 | 82% ≤ n < 87% | 2 | < n + 13% |
16 | n < 82% | 3 | < n + 17% |
≥ 32 | - | 3 | < n + 10% |
- If data compression is enabled, the formula for calculating the CPU usage after the Agent starts is as follows:
in which, c indicates the number of CPUs, p indicates the number of compression threads, and n indicates the CPU usage before the Agent starts.
- If data compression is disabled, the Agent occupies less than 10% of memory. The formula for calculating the CPU usage is as follows:
By default, data compression is enabled for Linux block migrations. To disable this function, see How Do I Disable Data Compression When the CPU Usage Is Too High During a Linux Block-level Migration?
- Memory Usage (of Data Cache)
- CPU Usage