| |
| UFS-Impaired-Storage |
| ==================== |
| |
| Contents |
| -------- |
| |
| 1. Overview |
| 2. Quick reference guide |
| 3. Detailed information |
| |
| 1. Overview |
| ----------- |
| |
| Flash storage performance can be degraded over time due to the storage and |
| file system aging as well as complicated internal structure. |
| Impaired Storage emulate degraded storage latencies by adding delay for each |
| I/O request. |
| |
| |
| 2. Quick reference guide |
| ------------------------ |
| |
| * Case1: delay all read requests by 1.5x |
| echo 150 > /sys/.../impaired/read_delay_percent |
| echo 1 > /sys/.../impaired/enabled |
| |
| * Case 2: delay all write requests by 300us |
| echo 300 > /sys/.../impaired/write_delay_us |
| echo 1 > /sys/.../impaired/enabled |
| |
| * Case 3: delay both read and write requests by 2x, then add 100us |
| echo 200 > /sys/.../impaired/read_delay_percent |
| echo 200 > /sys/.../impaired/write_delay_percent |
| echo 100 > /sys/.../impaired/read_delay_us |
| echo 100 > /sys/.../impaired/write_delay_us |
| echo 1 > /sys/.../impaired/enabled |
| |
| * Case 4: emulate impaired read latencies. |
| echo fragftl > /sys/.../impaired/read_model |
| echo 1 > /sys/.../impaired/enabled |
| |
| |
| 3. Detailed information |
| ----------------------- |
| |
| http://go/impairedstorage |
| |
