# Configure your workload on Amazon EC2 for torn write prevention
<a name="configure-twp"></a>

Torn write prevention is enabled by default on [supported instance types with supported volumes](supported-block-sizes.md). You don't need to configure any additional settings to enable torn write prevention.

**Note**  
Workloads that don't support torn write prevention have no performance impact. You don't need to make any changes for these workloads.  
Workloads that support torn write prevention, but are not configured to use it, continue to use the doublewrite buffer and don't receive any performance benefits.

To configure your MySQL or MariaDB software stack to disable the doublewrite buffer and use torn write prevention, complete the following steps:

1. Configure your volume to use ext4 file system with the BigAlloc option and set the cluster size to 4 KiB, 8 KiB, or 16 KiB. Using BigAlloc with a cluster size of 4 KiB, 8 KiB, or 16 KiB ensures that the file system allocates files that align with the respective boundary.

   ```
   $  mkfs.ext4 -O bigalloc -C {{4096|8192|16384}} {{device_name}}
   ```
**Note**  
For MySQL and MariaDB, you must use `-C 16384` to match the database page size. Setting allocation granularity to a value other than a multiple of the page size can result in allocations that might be mismatched with torn write prevention boundaries of the storage device.

   For example:

   ```
   $  mkfs.ext4 -O bigalloc -C 16384 /dev/nvme1n1
   ```

1. Configure InnoDB to use the `0_DIRECT` flushing method and turn off InnoDB doublewrite. Use your preferred text editor to open `/etc/my.cnf`, and update the `innodb_flush_method` and `innodb_doublewrite` parameters as follows:

   ```
   innodb_flush_method=O_DIRECT
   innodb_doublewrite=0
   ```

**Important**  
If you are using Logical Volume Manager (LVM) or other storage virtualization layer, make sure that the starting offsets of the volumes are aligned on 16 KiB multiples. This is relative to the underlying NVMe storage to account for the metadata headers and superblocks used by the storage virtualization layer. If you add an offset to the LVM physical volume, it can cause misalignment between the file system allocations and the NVMe device's offsets, which would invalidate torn write prevention. For more information, see `--dataalignmentoffset` in the [Linux manual page](https://man7.org/linux/man-pages/man8/pvcreate.8.html).