Renamed Directory Handling in NDMP Incremental File Migration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The Network Data Management Protocol (NDMP) fails to correctly migrate renamed directories during incremental backup and restore operations, especially when source and storage devices support incompatible data formats, leading to mismatched backup data and potential data loss.
Innovation Solution
An EMC cloud tiering appliance uses NDMP to perform data format conversions and employs inodes to correctly migrate renamed directories by identifying and managing inode numbers, ensuring accurate migration of file and directory data between source and storage devices with incompatible formats.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If NDMP incremental backup is used to migrate files and directories, then backup efficiency is improved by copying only modified files, but renamed directories are incorrectly migrated as empty directories causing data loss
Solution Approach 1:
The patent introduces an intermediary mechanism that tracks directory rename operations through inode number comparison. When a directory is renamed, the system detects this through inode tracking and manually transfers the directory contents to the backup storage device, ensuring that renamed directories are not mistakenly treated as empty. This intermediary tracking layer resolves the contradiction by maintaining data integrity during efficient incremental backups.
Solution Approach 2:
The system implements feedback mechanisms by monitoring directory operations and comparing inode numbers to detect renames. When a rename is detected, the system receives feedback about the actual state of the directory and adjusts the backup process accordingly, ensuring that renamed directories are properly handled rather than being incorrectly copied as empty.
2Adaptability or versatility
If NDMP copy is used for file migration between devices with incompatible data formats, then migration capability is enabled, but data format compatibility issues cause migration failures
Solution Approach 1:
The patent employs an intermediary data format conversion layer that translates between different data formats of source and storage devices. This intermediary mechanism enables NDMP copy to function across devices with incompatible formats by converting the source device's data format into a format compatible with the storage device, thus resolving the compatibility issue while maintaining migration capability.
3Ease of operation
If standard NDMP backup operations are used, then backup process is simple and automated, but renamed directories are not correctly handled leading to backup data mismatch
Solution Approach 1:
The patent introduces an intermediary directory tracking mechanism that operates transparently within the standard NDMP backup process. This intermediary layer monitors directory operations, detects renames through inode comparison, and manually ensures correct data transfer for renamed directories. The solution maintains backup simplicity while improving accuracy by operating as an transparent enhancement rather than a complex replacement.
Data Source
AI summary
Renamed directory handling for incremental file migration is described. A directory is stored in a storage device. An inode number associated with the directory in a directory table is identified. A determination is made whether the inode number equals an inode number associated with another directory in the directory table. At least one of a file and a subdirectory associated with the directory in the file system is stored into the directory in the storage device if the inode number equals the inode number associated with another directory in the directory table.