A backup is not the goal. The goal is restoring the environment within an agreed time and with an agreed data loss. I write about designing a backup strategy, about copies that survive ransomware, about restore tests as a routine part of operations, and about what else, beyond the data, is needed for a restore to be possible at all.
A log file more than ten times the size of the data file almost always means a database in the FULL recovery model without log backups. How log truncation works, what log_reuse_wait_desc shows and how to bring the .ldf file back to a sensible size in one go.
SQL Server Express has no SQL Server Agent and no maintenance plans, so backups have to be scheduled some other way. A PowerShell script with sqlcmd run from Task Scheduler under a gMSA, file retention, and restoring log backups on a second server as an equivalent of log shipping.
A virtual machine checkpoint sits on the same storage as the machine, grows with every write and depends on its parent disk. How the AVHDX chain works, when a checkpoint makes sense, and how to find the ones that stayed too long.
The backup job finishes with a “success” status every night, and the restore can still fail. How to write down RPO and RTO, run restore tests to a protocol and monitor the age of the last successful backup.
A snapshot of a domain controller's virtual machine is not a directory backup. System state backups, the deleted object lifetime, the AD Recycle Bin, four ways to restore, and the stages of forest recovery when no working controller is left.
A GitOps-managed cluster can be rebuilt from scratch in an hour, but the repository will not bring back volume data, secrets or API state. etcd snapshots in k3s, Velero, and a restore test to a separate cluster.