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These articles provide basic information and helpful recommendations concerning data access and recovery.

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Choosing better operating system for NAS recovery

Serving the major function of a network device for storing and sharing files NAS storage doesn't require a fully-featured operating system. Normally, the operating system is embedded by NAS vendor. The vendors offer a variety of operating systems for modern NAS devices in most cases principally based on Linux or BSD operating systems.

The article below helps to choose the best host operating system to recover lost data from your NAS storage.

Something about modern NAS

Most popular NAS storages available on the market these days are designed in this way: the network storage consists of one or more drives and is run by an embedded operating system. The drives in multi-drive NASes are normally combined into RAID system to increase operational speed and use storage as efficiently as possible.

With rare exclusions like, for example, hardware RAID of Promise Technology, most NAS retailers offer software solutions. Usually, they are similar in logical design and may differ in style, quality, power consumption, thermal design, noise level and, of course, firmware.

A version of the operating system kernel used for NAS firmware depends on NAS retailer. Among them the most widely applied operating system is a custom Linux version designed for embedded microprocessor. Each operating system usually works with its own file system type and its own version of software RAID drivers.

What host OS should I use to recover the data from my NAS?

As mentioned above, most NAS vendors offer custom versions of Linux operating system embedded in their NAS solutions. And most desktop versions of Linux OS support the same file system and RAID metadata types used in NAS firmware usually with a similar Linux OS.

Obviously, it would be much easier to work with the same host OS as in your NAS. Compatible Linux operating systems recognize RAID metadata, build (load) RAID, mount the file system and let you access the data from your NAS immediately.

Note: When you recover data using host Linux OS, it's strongly recommended to backup ALL the critical data before you restart your NAS.

Why not macOS?

Modern Apple macOS operating system recognizes RAID structures created by NAS but not all NAS file systems. The main disadvantage of using macOS as host OS for NAS recovery is that, if it detects and recognizes RAID structures, it can update them to the latest version or 'supported configuration'. For example, RAID10 can be reset to a simple pair of RAID0 with loss of all information about mirroring.

Note: When you recover data using host Apple macOS, it's strongly recommended to backup ALL the critical data before you restart your NAS.

And what about Windows?

Any version of Microsoft Windows OS doesn't recognize NAS file systems and its RAID metadata eliminating the possibility of implicit data damage. Working with NAS from Windows OS you may cause damage to your data only by an incorrect action such as data modification with special tools, initialization or formatting NAS drives and so on.

If you are not sure what steps you should take in the process of data recovery from your NAS, use Windows as host operating system as the most reliable OS that will protect your data from unexpected actions of the operating system.

Note: some drivers on Windows OS offered by third-party retailers for Linux file systems may cause damage or modification to NAS file systems. For this reason it's strongly recommended to disable all the drivers which can conduct read-write operations on Linux file systems before starting data recovery process from your NAS.

Faster NAS or danger to data?

With the aim to increase operational speed of the NAS storage some retailers extend its file system. Such extensions of the file system can be not supported by your desktop Linux. If you mount the file system in a read-only mode, desktop Linux will report file system errors. And if you run 'fsck' tool or mount file system in a read-write mode, this can permanently destroy your data.

And how to recover and not to lose the data completely? First of all, mount NAS file systems in the 'ro' (read-only) mode only! Moreover, your data recovery chances will be significantly increased with a reliable data recovery software able to support retailer-specific file system extensions. SysDev Laboratories offer UFS Explorer software making the entire data recovery process an easy and safe operation.

Deleted files recovery

Normally, due to NAS specifics most data recovery software doesn’t work with the storage directly. To recover lost data from your NAS you should disassemble the storage, connect the drives to a recovery PC and run data recovery software.

Powerful tools of UFS Explorer software maximize the chances for successful data recovery from your NAS. For multi-drive NAS we offer professional software specially designed to work with complex RAID systems. This software require user’s minimum efforts while supporting semi-automatic reconstruction of RAID software.

After completing recovery you may continue using your NAS. For this you should re-assemble NAS drives keeping their order and reboot the device. Further on you may store recovered data on your working NAS.

Note: As already mentioned above, any writing operations to NAS file system cause permanent data loss. For this reason you should be careful not to mount the file system in read-write mode, and rather in read-only.

Recovered data, put-back drives... Where are my files?

When you put the drives back into your NAS you should watch the order. Otherwise normal boot process of your NAS will fail and you won't get the files back.

Another danger your files may face is update of RAID metadata caused by desktop Linux OS. Linux OS kernel and the version of software RAID may differ. If Linux updates RAID metadata, the metadata of a new format can be not recognized by NAS anymore. This can result in auto-repair of NAS destroying current RAID and creating a new empty storage with default settings.

It's strongly recommended to backup ALL the critical data before you restart your NAS.

Last update: July 5, 2018

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