VCF 9.1.1.0 Management Services Backup fails using SFTP server

Products

• VCF Operations

Issue/Introduction

A newly deployed VCF 9.1.1  environment experienced issues after configuring backups. After adding an SFTP backup target, we started encountering errors while backing up VCF components.

In Tasks, Subtasks we see the following as Failed for "Backup SDDC LCM components using SDDC lifecycle service" & "Back up VCF services runtime components"

Environment

VCF 9.1.1

Cause

Operationsmanager.log shows the following error:

This is a space issue

2026-09-15T15:19:13.903Z INFO vcf_om 1796 [####### traceId="0000000000000000" spanId="0000" threadId="sshd-SshClient[11c2ae9f\]-timer-thread-1" class="o.a.s.c.s.helpers.SessionHelper" method="disconnect" line="1183"] Disconnecting(ClientSessionImpl[[email protected]/xxx.xx.xx.xx:22]): SSH2_DISCONNECT_PROTOCOL_ERROR - Detected IdleTimeout after 600598/600000 ms.
2026-09-15T15:19:13.909Z DEBUG vcf_om 1796 [#####@#### traceId="#######" spanId="bade" threadId="http-nio-127.0.0.1-####-exec-6" class="c.vmware.vcf.secure.ssh.SshExecuter" method="executeCommandAndHideWords" line="717"] End of execution of command [df -BG <absolute_Datastore_path>/dev/null | awk 'NR>1 {print $4}' | head -1], Status: 0
Output:
Error output:
Command timed out: true
2026-09-15T15:19:13.910Z DEBUG vcf_om 1796 [####@#### traceId="#####" spanId="bade" threadId="http-nio-127.0.0.1-####-exec-6" class="c.v.vcf.secure.ssh.CommandResult" method="isSuccessful" line="72"] Validating operation with exit code '0' and accepted success exit codes '[]'
2026-09-15T15:19:13.910Z WARNING vcf_om 1796 [####@#### traceId="#####" spanId="bade" threadId="http-nio-127.0.0.1-####-exec-6" class="c.v.v.c.f.p.b.r.v.BackupLocationValidator" method="validateDiskSpace" line="442"] Could not determine disk space for path </<absolute_Datastore_path>
2026-09-15T15:19:13.911Z DEBUG vcf_om 1796 [####@#### traceId="#####" spanId="bade" threadId="http-nio-127.0.0.1-####-exec-6" class="c.v.e.s.c.v.util.ResponseUtil" method="buildResponse" line="99"] Build validation response: {"errorCode":"BACKUP_DESTINATION_DISK_SPACE_VALIDATION.info","arguments":["<absolute_Datastore_path>"context":{"severity":"INFO","bundleName":"com.vmware.evo.sddc.common.validation.errors.messages"},"message":"Sufficient disk space available on backup server <absolute_Datastore_path","remediationMessage":"Free up disk space on the backup server to ensure at least {3} GB is available. 

 

Resolution

Refer to the VMware Cloud Foundation at Configure an External SFTP Server for SDDC Manager and NSX Manager Backups