BlueStore fragmentation tool
As a storage administrator, you will want to periodically check the fragmentation level of your BlueStore OSDs. You can check fragmentation levels with one simple command for offline or online OSDs.
For BlueStore OSDs, the free space gets fragmented over time on the underlying storage device. Some fragmentation is normal, but when there is excessive fragmentation this causes poor performance.
The BlueStore fragmentation tool generates a score on the fragmentation level of the BlueStore OSD. This fragmentation score is given as a range, 0 through 1. A score of 0 means no fragmentation, and a score of 1 means severe fragmentation.
| Score | Fragmentation Amount |
|---|---|
|
0.0 - 0.4 |
None to tiny fragmentation. |
|
0.4 - 0.7 |
Small and acceptable fragmentation. |
|
0.7 - 0.9 |
Considerable, but safe fragmentation. |
|
0.9 - 1.0 |
Severe fragmentation and that causes performance issues. |