Backup on Margrop Blog

Your Photos May Have No Backup: Why a NAS Alone Is Not Enough

Wed, 29 Jul 2026 08:00:00 +0800

The short answer

If your photos exist only on a phone, a computer, and one NAS, you may not have three backups. You may have three doors leading to the same room. A lost phone, ransomware on the NAS, an accidental synchronized deletion, or a house fire can remove all three doors at once.

The rule worth remembering is 3-2-1: at least 3 copies, on at least 2 types of media, with at least 1 copy offsite. The stronger version is 3-2-1-1-0: add 1 offline or immutable copy, and verify that recovery has 0 undetected errors.

Stop Running rsync Blindly: Preview Differences Before a Safe Incremental Sync

Sat, 11 Jul 2026 13:30:00 +0800

The short answer

The best rsync habit is not memorizing more switches. It is separating every risky job into two stages: generate a dry-run plan first, review it, and only then perform the real incremental sync. Deletion should be a separate, explicit permission rather than a hidden default.

The common rsync -n -avz --delete --out-format="%n" pattern can list paths that may change, but %n only preserves the name. A safer machine-readable plan uses --itemize-changes together with %i, so each line identifies an addition, update, deletion, or metadata change.

RAID Is Not Backup: How to Choose the Right NAS Layout for Synology, fnOS, and Unraid

Sat, 11 Jul 2026 12:00:00 +0800

The short answer

RAID primarily keeps a NAS available when one or more drives fail. Backup restores data after deletion, ransomware, filesystem damage, theft, fire, or a failed NAS. You normally need both.

On Synology, SHR-1 is the practical default for many homes, while larger and more critical arrays deserve SHR-2 consideration. On fnOS, choose the filesystem, storage mode, drive count, and backup destination as one design. On Unraid, understand that the classic Array is not a conventional striped RAID: data disks keep independent filesystems while one or two parity disks provide failure recovery.

A useful starting rule is: mirror two-drive systems; use single-drive redundancy when capacity matters and a separate backup exists; seriously consider dual-drive redundancy as drive count and individual drive capacity grow. Anything irreplaceable still needs an offline or off-site copy.

OpenClaw Backup Failure Investigation and Fix: From Two Broken Schedules to a Fully Restored Automation Pipeline

Mon, 13 Apr 2026 09:30:00 +0800

This post is a full incident review, not because the failure was dramatic, but because it was a very typical automation problem.

Two machines lost their automatic OpenClaw backups at the same time: a local macOS machine and a remote VPS. Manual runs worked on both sides, and the archives could still be synchronized to the NAS, but the scheduled jobs were unreliable. At first glance it looked like “the scheduler did not fire.” In reality, the root cause was spread across scheduling, permissions, locking, logging, and even the way I validated the schedule.

That combination is what makes these incidents annoying: every individual piece looks almost fine, yet the full pipeline still fails.

ProxmoxVE 6.3 uses commands to back up Synology virtual machines

Thu, 21 Jan 2021 18:16:22 +0800

Since the Synology virtual machine in my ProxmoxVE runs on a LUN passthrough disk, I cannot click backup directly in the Web interface. DSM virtual machine backup process: Stop the virtual machine -> Unmount the hard disk -> Back up the virtual machine -> Mount the hard disk -> Start the virtual machine It is really troublesome and error-prone to do this entirely through the Web interface. So I studied the command-line workflow.