[Feature] Data Synchronization Across Storage Devices

请确认以下事项

• 我已确认阅读并同意 AGPL-3.0 第15条 。
  本程序不提供任何明示或暗示的担保，使用风险由您自行承担。

• 我已确认阅读并同意 AGPL-3.0 第16条 。
  无论何种情况，版权持有人或其他分发者均不对使用本程序所造成的任何损失承担责任。

• 我确认我的描述清晰，语法礼貌，能帮助开发者快速定位问题，并符合社区规则。

• 我已确认阅读了OpenList文档。

• 我已确认没有重复的问题或讨论。

• 我认为此问题必须由OpenList处理，而非第三方。

• 我已确认此功能尚未被实现。

• 我已确认此功能是合理的，且有普遍需求，并非我个人需要。

需求描述

During use, I found that the program lacks a convenient data backup solution. It would be highly beneficial if it could support data synchronization between two devices or more, similar to RAID 1.
Just a humble suggestion—thank you to the developers for your great work.

实现思路

When writing data, it can be synchronized to another storage device. This process runs in the background and can be asynchronous. However, when using two network storage devices, some caching may be necessary to ensure stable write performance.

附加信息

No response

The issue names no files, tests, or code entry points. Start with the OpenList documentation and trace the existing data-write path; define synchronization for multiple devices, including asynchronous background work and caching for network storage, then verify that writes remain consistent across devices.