fix: sync to x replace fuser with mtime check#151
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otenim merged 4 commits intodevelop/r36.4.0from Apr 23, 2026
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fuser scans /proc/*/fd for all processes and resolves each symlink via stat(), which causes excessive NFS round-trips when destinations include a NAS mount. This results in severe per-file latency inside the transfer loop. Replace the fuser-based open-file check with a modification time check using stat -c %Y. Files modified within the last 10 seconds are considered active and skipped. This avoids any NFS network I/O for the active-file guard while remaining reliable for the mcap recording use case.
Replace the hardcoded 10s mtime guard with a configurable parameter sync_to_x_active_file_threshold_sec (default: 30s). This allows operators to tune how long after recording ends a file is held back from transfer.
Verified on both NAS and external SSD hardware. How to verify: Check transfer speed with NAS and external SSD. Improvements: Resolved the transfer bandwidth limitation issue by adjusting the rsync bandwidth limit to 200m. Limitations: None.
citruscosmos
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citruscosmos
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otenim
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Apr 22, 2026
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Request: fix stat failure fallback in the active-file check
file_mtime=$(stat -c %Y "$mcap_file" 2>/dev/null || echo 0)
now=$(date +%s)
if [ $((now - file_mtime)) -lt {{ sync_to_x_active_file_threshold_sec }} ]; then
continue
fiWhen stat fails, file_mtime falls back to 0, so now - 0 is a huge number and the condition is false — the file is not skipped and the script proceeds to rsync, then rm -f on success.
Could you change the fallback to skip on stat failure instead? e.g.
if ! file_mtime=$(stat -c %Y "$mcap_file" 2>/dev/null); then
echo "Skipping (stat failed): $mcap_file"
continue
fi
now=$(date +%s)
if [ $((now - file_mtime)) -lt {{ sync_to_x_active_file_threshold_sec }} ]; then
echo "Skipping recently modified file (active within {{ sync_to_x_active_file_threshold_sec }}s): $mcap_file"
continue
fiThe file will be retried on the next timer tick, which is the safer default.
When stat fails, the previous fallback (|| echo 0) caused now-0 to be a large number, bypassing the active-file guard and allowing rsync followed by rm -f on a file whose state was unknown. The file is now skipped with a log message and retried on the next timer tick.
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Description
This PR replaces the
fusercommand with anmtime(modification time) check in thesync-to-xdata synchronization process.Previously, using
fusercaused significant slowdowns when operating over network file systems (NFS). Using anmtime-based check provides a much more efficient way to determine if a file is still actively being written to.Additionally, this PR includes the following updates:
mtimeis now configurable via an Ansible parameter.rsyncbandwidth limit (increased from 100m to 200m) to resolve transfer bottlenecks.How to verify
sync-to-xconfiguration.Improvements
fuserdependency.mtimethreshold configurable.Limitations