---
title: "Make application-consistent virtual machine backups"
description: "Ask the guest to flush databases before the hypervisor copies disks, or the restored machine may boot with a torn write."
url: https://howtobackupvm.com/en/blog/application-consistent-backups/
---

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# Make application-consistent virtual machine backups

Ask the guest to flush databases before the hypervisor copies disks, or the restored machine may boot with a torn write.

Published 2026-04-09· HowToBackupVM editors

A crash-consistent copy is whatever was on disk at the instant of the snapshot. Most file systems repair that on boot. A database may replay logs, or it may refuse to open if a transaction was half written.

Application-consistent jobs call VSS on Windows or a pre-freeze script on Linux so the database writes its logs and pauses writes. After the snapshot, the post-thaw script lets traffic resume. Test that the scripts exist on the guest and that the backup report says the quiesce succeeded.

If the guest cannot be quiesced, take a dump from the database itself and store that dump with the virtual machine backup.

## Questions

On storage that does not share the production datastore, rack power, or backup admin password.

A boot of the restored guest on an isolated network, plus a recent application record.

Daily for two to four weeks, weekly for a few months, and monthly for the period your contract names.

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