Understanding Common rsync Backup Errors: code 24, code 11, code 10, and File I/O Errors

Original Question or Issue:

The customer reported rsync errors during and after a backup operation and requested an analysis of the cause.

Environment:

• Product - FileCloud Server
• Version - 23.253
• Platform - Linux

Steps to Reproduce:

• Configure an rsync backup of the FileCloud storage.
• Run the backup while the FileCloud instance is actively serving users and files are being modified.
• Observe the rsync output during or after the backup completes.
• Depending on the underlying storage condition:
  • If files are modified, moved, or deleted during the backup, rsync may report warning code 24.
  • If the destination storage experiences filesystem or I/O issues, rsync may report Input/output error (5), code 11, and subsequent code 10/Broken pipe errors.

Error or Log Message:

• rsync warning: some files vanished before they could be transferred (code 24)
• ftruncate failed: No such file or directory (2)
• ftruncate failed: Input/output error (5)
• close failed: Input/output error (5)
• rsync error: error in file IO (code 11)
• rsync error: error in socket IO (code 10)
• Broken pipe (32)

Defect or Enhancement Number:

Cause:

There are two distinct scenarios:

1. rsync Warning Code 24
   • This warning occurs when files are modified, renamed, moved, or deleted after rsync has generated its file list but before it copies the files.
   • This is common on active systems where files continue to change during the backup and does not generally indicate a failed backup.
2. File I/O Errors (Codes 11 and 10)
   • Errors such as Input/output error (5) and error in file IO (code 11) indicate that rsync encountered a problem writing to the destination storage.
   • Possible causes include:
     • Filesystem corruption
     • Disk hardware issues
     • Network storage (NFS/NAS) connectivity problems
     • Mount interruptions
     • Insufficient disk space or available inodes
   • The subsequent Broken pipe (32) and error in socket IO (code 10) are secondary errors caused by the receiver process terminating after the file I/O failure.

Resolution or Workaround:

For Code 24:

• If the backup completed successfully and no other errors were reported, no action is generally required.
• This warning is expected when backing up a live system with files that are actively changing.
• If necessary, perform backups during maintenance windows or use filesystem snapshots to obtain a consistent backup.

For File I/O Errors (Codes 11 and 10):

• Verify whether the backup destination is local storage or a network-mounted filesystem (NFS/NAS).
• Review system and storage logs at the time of the failure for disk, filesystem, mount, or connectivity issues.
• Confirm that the destination has sufficient free disk space and available inodes.
• If using network storage, verify that no temporary disconnects or storage-side issues occurred during the backup.

Notes: