Problem solved with #LeonidS help, Thanks!

Resolving Upload Delays Related to ZFS Sync Settings

When managing photo uploads, users may encounter delays or errors that can disrupt their experience. One common issue stems from the way the ZFS (Zettabyte File System) handles data synchronization, which can significantly impact upload performance. This article explores how adjusting the ZFS sync settings can resolve these upload-related errors.

Understanding the Problem

ZFS has a built-in synchronization mechanism that controls how data is written to disk. The default setting is sync=standard, which ensures data integrity by writing data to disk immediately. However, this can introduce latency, especially during bulk uploads, as each file must be fully written before the upload process can complete.

Symptoms of the Issue:

• Slow upload times when adding multiple photos to albums.
• Delayed responses in the application during the upload process.
• Possible notifications for each individual photo upload, causing notification overload.

Adjusting ZFS Sync Settings

To alleviate these issues, adjusting the ZFS sync setting for the relevant dataset can be beneficial. Setting sync=always ensures maximum data integrity but at the cost of performance. Conversely, setting it to sync=disabled allows for faster uploads, but it introduces a risk of data loss in the event of a crash.

For optimal performance in scenarios where data integrity is not as critical , you can set sync to disabled or standard based on your use case. But in this case it may cause an error (such as during photo uploads where users can re-upload failed photos due to lack of synchronization) so the best option is 'always'. Here's how to do this:

# Set sync to disabled for better performance during uploads
zfs set sync=always rpool/USERDATA/user_dataset

where 'user_dataset' is the folder that I want to make sure will be synchronized very quickly. You can have multiple datasets, For more information see the official documentation.https://docs.oracle.com/cd/E19253-01/819-5461/idx/index.html