transaction log backup format sector size I am trying to backup a log file in SQL Server but I obtain an error message while yesterday I did it successfully. 
The only difference between yesterday and now is that I just truncate the principal table in the database.
The error message in french I get is the following:

USE master BACKUP LOG MQ  TO DISK = 'D:\MSSQL\BackupToSendToFtp\MQLog.bak'



  Impossible d'utiliser le fichier de sauvegarde
  'D:\MSSQL\BackupToSendToFtp\MQLog.bak' car il a été formaté à
  l'origine avec une taille de secteur de 512 et se trouve maintenant
  sur une unité dont la taille de secteur est 4096.


Which in English should be: 


  Cannot use the backup file 'D:\MSSQL\BackupToSendToFtp\MQLog.bak'
  because it was originally formatted with sector size 522 and is now on
  a device with sector size 4096.


A few days ago I upgraded the Azure VM to get a more powerful one. Can this be the main cause of the backup failure? 

If yes then why did the backup succeed yesterday?
Correct. You can't restore backups to storage with a different sector size (this is something to do with the way the log is structured internally where it would be unsafe to do so - there's a big article on it which is as clear as mud).

Are you using Storage Spaces? 


  The problem with all of this is that the when creating a virtual disk
  with Storage Spaces, if you do not specify a LogicalSectorSize via the
  Powershell cmdlet, the system will create a virtual disk with a
  LogicalSectorSize equal to the greatest PhysicalSectorSize of any disk
  in the pool. This means if you have SSD’s in your pool and you created
  the virtual disk using the GUI, your virtual disk will have a 4k
  LogicalSectorSize.


If so then you're out of luck, you can reformat the Azure disks as described to use 512 byte sectors but you'll then get a massive and permanent performance hit.

There's no way to backup/restore that database onto the new storage. You'd have to export the database schema and data from your old storage and import it to a new database on the new storage. Crazy, I know.