Error result of backup execution: "either sftp server disk full or bad directory path or check if the directory path length is beyond 260 character limit on windows server"

Products

• VMware NSX

Issue/Introduction

• Backups fail with the error “either sftp server disk full or bad directory path or check if the directory path length is beyond 260 character limit on windows server”. 
• Editing the backup configuration may result in the error message "Error: One of: 1. invalid directory path; 2. sftp server disk is full. (Error code: 29111)"
• 
• The SFTP server is a Linux host with adequate storage space available.
• /var/log/syslog or /var/log/proton/nsxapi.log may have messages like the following:
  • API result did not pass validationField level validation errors: {value BACKUP_URI_NOT_FOUND of property cluster_backup_statuses[0].error_code is not one of the allowed values [BACKUP_NOT_RUN_ON_MASTER, BACKUP_SERVER_UNREACHABLE, BACKUP_AUTHENTICATION_FAILURE, BACKUP_PERMISSION_ERROR, BACKUP_TIMEOUT, BACKUP_BAD_FINGERPRINT, BACKUP_GENERIC_ERROR, UPGRADE_IN_PROGRESS]}
• The filesystem structure for the backup may be created - e.g. cluster-node-backups/<NSX version>-<UUID>/backup-2025-05-28T02_00_00UTC, but the directory is empty.

Environment

VMware NSX

Cause

Unrecognized path during backup. Although the path is valid and the directory structure is being created, the issue may still occur.

This can also happen if the SFTP server already contains the folder specified in the directory path. In that case, NSX cannot create the folder because it already exists.

Resolution

Edit the backup path to include a trailing forward slash.  e.g.: /home/sftpadmin/NSX/

If the SFTP server already contains the folder specified in the directory path, delete the folder and allow NSX Manager to recreate it