Unable to restore zipped backup

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Tomas
Posts: 3
Joined: Tue Apr 08, 2025 10:55 am

Unable to restore zipped backup

Post by Tomas »

Hello,

I have a problem with restoring data that is zipped. I tried .sz and .zip. With .sz the recovery completes successfully without errors, but only some files are unzipped, not all.
When I tried .zip, the restore fails right at the beginning with this error for every file: Error message: "Unzipping to an FTP or other Internet folder is not supported. at 0000000002AA5663"

My goal is:
Incremental backups with weekly checkpoints with a retention period of 30 days with no or fast compression.

My settings:

Internet protocol settings:
- SFTP
- Implementation: SecureBlackBox

Versioning:
- Keep older versions when replacing: 3 per file
- Delete old file versions after 30 days
- Filename Encoding

Synthetic Backups:
- Use Synthetic Backups
- Use Checkpoints every Week
- Remove unneeded incrementals older than 30 days - Thin out checkopint dynamically

Compression:
- Compress Each File Individually - Format: tried both: .zip and .sz
- Compression: tried None and Fast

Thank you, if any more information is needed, I will provide it.
tobias
Posts: 1936
Joined: Tue Mar 31, 2020 7:37 pm

Re: Unable to restore zipped backup

Post by tobias »

Can you send log files to support@syncovery.com? It would enable me to see all relevant settings and have more context.
Tomas
Posts: 3
Joined: Tue Apr 08, 2025 10:55 am

Re: Unable to restore zipped backup

Post by Tomas »

I send the log files to support@syncovery.com

I will also add that I noticed that files that are not unpacked, when viewed through szarchiver, contain MD5.TXT and a directory shown in blue in the archive content.
Files that are unpacked contain only the given file.
tobias
Posts: 1936
Joined: Tue Mar 31, 2020 7:37 pm

Re: Unable to restore zipped backup

Post by tobias »

Hello,
it is correct that zip files cannot be unpacked and uploaded via SFTP in a single go.

The same applies to Synthetic Backup files.

Therefore, please use a local temporary folder as restore destination (change the left side in the restore profile).

Then, use a second profile to upload the data.

When using Synthetic Backup, you can have two kinds of zip or sz files:

1. Initial File: contains the whole file like a normal .zip file.
2. Deltas: these may contain various separate virtual files containing specific block ranges. A MD5.txt file contains the checksum for the whole file.

The Sz format can unpack initial files directly to an Internet protocol, but not Synthetic Backup chains that consist of the initial file + deltas.

The missing features might be going to be added in a future version.

Concerning Synthetic Backup, please consider wisely if it's worth it. You can look at the backup chains for larger files to see if disk space was actually saved or not. It is only useful for large database files and disk images.
Tomas
Posts: 3
Joined: Tue Apr 08, 2025 10:55 am

Re: Unable to restore zipped backup

Post by Tomas »

Thank you, after unzipping to a temporary folder the recovery works as it should.

If I may, I have 2 questions:

1.) In my case I will be backing up files that have already been backed up, so they are basically blocks of the same size (32 MB each). So I assume that in my case "Synthetic backup" is really unnecessary. Just use Standart Copying mode and only new 32 MB blocks will always be copied. Am I right?

2.) If I want to keep 3 copies of data, let's say daily backup, 14-day and monthly - do I have to create 3 different profiles or can it be set up somehow in one?
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