Prevent setting record or block sizes below 4K and warn when changing record size
There are multiple cases when users shoot their foot by setting dataset record or zvol block sizes too small, that negatively impact performance due to huge CPU processing overhead, pool storage efficiency, but also can get system out of memory due to inability of present (11.1 and above) ARC to efficiently store blocks less then 4KB.
I think we should completely forbid record/blocks less then 4KB there (remove from the lists), and warn users about possible negative effects for sequential I/O performance and space efficiency if they are setting value less then the default one we are calculating now for zvols, based on pool topology.
- File 55980-zvol-block-size.png 55980-zvol-block-size.png added
- File 55980-dataset-record-size.png 55980-dataset-record-size.png added
- Status changed from Ready for Testing to Failed Testing
Testing with FreeNAS Mini updated to INTERNAL53:
Go to Storage/Pools and add a new Zvol to an existing pool. Click "ADVANCED MODE" and verify the "Block size" can be no less than "4K" (zvol-block-size.png). Confirm changing "Block size" to smaller than 4K is not an option for an existing Zvol.
Go to Storage/Pools and add a new dataset to an existing pool. Click "ADVANCED MODE" and review the "Record Size" option. Options exist to set the record size to "512", "1K", and "2K" (dataset-record-size.png). Editing an existing dataset also has options to set the record size to less than 4K.
- File Screen Shot 2018-11-29 at 4.22.18 PM.png Screen Shot 2018-11-29 at 4.22.18 PM.png added
- File Screen Shot 2018-11-29 at 4.23.39 PM.png Screen Shot 2018-11-29 at 4.23.39 PM.png added
- File Screen Shot 2018-11-29 at 4.23.50 PM.png Screen Shot 2018-11-29 at 4.23.50 PM.png added
- File Screen Shot 2018-11-29 at 4.32.34 PM.png Screen Shot 2018-11-29 at 4.32.34 PM.png added
Test Passed FreeNAS-11.2-INTERNAL57
Note: Spoke to developer, requested I add a ticket to fix the issue of highlighting more than one option in the drop down field (anything under 4k is highlighted with current acceptable choice, but nothing can be selected/saved/updated below 4k).