Home > Workload Solutions > SQL Server > Best Practices > Intel-Based SQL Server Best Practices on Dell PowerEdge R740 and PowerMax 2000 > Database Best Practices > Performance Best Practices > SQL Server 2019: Forced Unit Access
In this best practice, we implemented Forced Unit Access (FUA) to improve write performance of the SQL Server database.
Category | SQL Server 2019 Enterprise |
Product | SQL Server |
Type of best practice | Performance Optimization |
Day and value | Day 3, Fine Tuning |
Overview
FUA is a bit that is sent with writes to storage that improves database performance and durability. Kernel FUA was not supported prior to Linux 4.18, which resulted in device level flushing that was inefficient and could impact storage I/O performance. SQL Server addressed storage inefficiency by minimizing flushes, but there was still room for improvement.
The Linux 4.18 and later Linux XFS file systems support the FUA bit. The 4.18 Linux Kernel allows the XFS file system and a device supporting FUA writes to avoid the additional block device flush requests. Using the Linux XFS file system and the FUA bit can significantly improve performance of write intensive workloads.
Recommendation
Implementing FUA resulted in slight performance gains for the following metrics:
Implementing FUA resulted in no changes to the following metrics:
Given these results, we recommend implemented the FUA as a Day 3 fine tuning practice.
Implementation Steps
To set the trace flag and writethrough and alternatewritethrough option, perform the following steps:
Additional Resources