docs: enhance Write Back section with filer.remote.sync comparison

Enhanced the "Write Back changes to Remote Storage" section to explain
both continuous sync (filer.remote.sync) and on-demand sync (remote.copy.local)
options. Added a detailed comparison table showing when to use each approach,
including features, use cases, and resource considerations.

Mount-Remote-Storage.md

@@ -51,18 +51,54 @@ This will update local metadata accordingly and still keep file contents that ar
 
 If the data on the cloud can changed often, you can create a cronjob to run it. Or you can add this command to the admin scripts defined in `master.toml`, to run it regularly.
 
-## Write Back changes to Remote Storage
+## Write Back Changes to Remote Storage
 
 If the mounted directory is only for reading, you can skip this step.
 
-If local changes need to be synchronized to the cloud storage, a separate process `weed filer.remote.sync -dir=xxx` should be started.
-This process will listen to filer change events, and write any changes back to the remote storage.
+If local changes need to be synchronized to the cloud storage, you have two options:
+
+### Option 1: Continuous Sync with `weed filer.remote.sync`
+
+For **continuous, real-time synchronization**, start a separate process `weed filer.remote.sync -dir=xxx`. This process will listen to filer change events and write any changes back to the remote storage automatically.
 
 ```
 weed filer.remote.sync -filer=<filerHost>:<filerPort> -dir=xxx
 ```
+
 The process is designed to be worry-free. It should automatically resume if stopped, and can reconnect automatically.
 
+**Use this when:**
+- You need real-time synchronization of all changes
+- Files are being continuously created, modified, or deleted
+- You want automatic background synchronization
+
+### Option 2: On-Demand Sync with `remote.copy.local`
+
+For **on-demand, batch synchronization** of local-only files, use the `remote.copy.local` command in `weed shell`. This is useful for one-time or scheduled backups.
+
+**Use this when:**
+- You have existing local files that were never synced to remote
+- You deleted filer logs and need to re-sync existing files
+- You want to run periodic batch backups via cron
+- You need fine-grained control over which files to sync (using filters)
+
+### Comparison: `filer.remote.sync` vs `remote.copy.local`
+
+| Feature | `weed filer.remote.sync` | `remote.copy.local` |
+|---------|-------------------------|---------------------|
+| **Type** | Long-running daemon process | One-time command |
+| **Synchronization** | Continuous, real-time | On-demand, batch |
+| **Trigger** | Automatic (on file changes) | Manual or cron-based |
+| **File Selection** | All changes in directory | Selective (with filters) |
+| **Use Case** | Active write workloads | Batch backups, recovery |
+| **Setup** | Requires separate process | Run in weed shell |
+| **Filters** | No (syncs everything) | Yes (`-include`, `-exclude`, size filters) |
+| **Dry Run** | No | Yes (`-dryRun`) |
+| **Force Update** | Automatic | Optional (`-forceUpdate`) |
+| **Resource Usage** | Continuous (low overhead) | Temporary (during execution) |
+| **Best For** | Production environments | Maintenance, recovery, scheduled backups |
+
+
 ## Copy Local-Only Files to Remote
 
 The `remote.copy.local` command synchronizes local-only files to remote storage. This is useful when you have files that were created locally and need to be backed up to remote storage.