NAS Recovery Course

NAS recovery course consists of five lessons. Most lessons come with hands-on tasks where you are offered to solve problems of different levels – from estimating the state of NAS disks to recovering data from disk image files coming from a real NAS. For each lesson, we developed a set of multiple choice tests to help you estimate how much you have learned about some or other NAS recovery aspect.

Lessons are arranged in order of increasing difficulty and fairly often a lesson refers to the material of the previous lesson. So we recommend you study the lessons in the order in which they are going.

In all lessons where data recovery software is needed for explanation or practice tasks, we use our ReclaiMe Pro. You can get a free trial version of ReclaiMe Pro on The trial version is enough to complete the tasks.

Also, you may find helpful to have at hand a textbook Logical Data Recovery, which formed the basis of this course.

Lesson 1 - NAS introduction

The lesson covers the NAS basics from what a NAS is to how data storage in a NAS is organized. Also, common NAS failures like operator errors, NAS disk subsystem failure, and NAS box failure are discussed.

Lesson 2 - NAS recovery preparations

The lesson covers NAS recovery preparations – what you need to ask a client before you start the recovery, how to estimate the state of hard disks to make a decision about cloning/imaging. Additionally, some tricks helping to determine sector size on a NAS disk are given.

Lesson 3 - NAS partitions

The lesson covers partitions in a NAS – typical NAS layout, the difference between old and modern NASes, and the effects of adding or upgrading disks in a NAS. Additionally, rolling upgrade resulting in several RAIDs on NAS disks is discussed in detail.

Lesson 4 - Filesystems in a NAS

From this lesson, you learn about commonly used filesystems in modern NASes, namely XFS and EXT family. These filesystems are considered from the undelete and unformat aspects.

Lesson 5 - NAS recovery workflow

This is the last lesson devoted to the general NAS recovery workflow covering all the aspects from collecting as much as possible information about the NAS and its failure to RAID recovery in case of damaged MD/LVM metadata.