Does Restore require Write access?

[cfieldgate]

Hi,

A simple question I couldn't find a direct answer to.

I have a disk formatted in BTRFS housed in a Synology box (as a single disk volume) which I use for Retrospect backups. If the Synology box fails, but the disk is fine, can I restore from the disk if I put it in a Windows 10 PC with a read-only BTRFS driver (Paragon)? Basically,, does the Retrospect Restore capability require Write access to the storage mediocre or not?

[jgowing]

Probably not. whilst the files system might be BTRFS, Synology sets up its disks using linux volume manager. which would not be recognised on a windows machine. Your disk will have 2 partitions, 1 Synology DSM System partition and 1 Data partition usually called Volume1.

However, if you were to boot a machine into a linux derivative and mount the drive it may well be visible.

For this to work your disk must be mounted on the motherboard and be supported & visible in the bios ( USB wont work) 

I would recommend creating a PartedMagic boot disk ( partedmagic.com ) boot your windows machine with it (It wont touch your Windows installation ) 

Use the disk tools in PartedMagic to identify and mount the disk, 

With luck your data may be recoverable

[Scillonian]

[In theory] Retrospect should be able to restore from read-only media.

More of problem will be trying to mount a Linux file system under Windows. I've found it bad enough try to reliably read the older (and simpler) ext2, ext3, and ext4 file systems. BtrFS is still evolving with all that entails. Also with Microsoft pushing out a new version of Windows 10 every six months, at present, what may work now will be broken with the next version of Windows 10.

Here are two more reliable solutions to consider:

1. Mount the BtrFS drive and an NTFS on a Linux OS and copy the Retrospect files from the BtrFS drive to the NTFS drive. (If you only have one computer then boot that computer from a Linux live CD/DVD/USB to perform the copy.)
2. If you have more than one computer and a network (preferably not wireless) then mount the BtrFS drive on a Linux OS and use SAMBA to share it over the network. A Linux live CD/DVD/USB can be used to do this if you do not have any native Linux computers.

Ultimatly the only way to really know what will work is physical test the emergency restore procedure and keep testing it until it works reliably. The time spent now will be rewarded later when the restore becomes a real event not a theoretical one.

"There are no successful backups, only successful restores."

[cfieldgate]

Many thanks to you both for replying - your advice is noted and appreciated - and has given me other reliable / trusted options to try. I have a SATA removable drive bay in one PC which I can use (and a CD drive), so I wasn't planning on going USB, and I have other NAS boxes to copy the recovered files to.

I will of course test my solution thoroughly before relying on it. The Linux live CD approach sounds like the best option for me. But I will also try out the Paragon driver https://www.paragon-software.com/home/linuxfs-windows/ as an academic exercise (a free 10 day trial licence is available).