Date: Jan 08
NV Version: Netvault 8 and higher
OS Version: All
Application version: N/A
Plugin version: File system version 7.1.6 and higher
To Implement the Access time before backup on restore we need to modify the ~netvault/config/nvfs.cfg file by adding the two lines below an existing section, the plugin should reset the access time back to the original value before it had to read the file during backup.
This will only restore the access restore time in this way to backups that have been made after the changes to the ~netvault/config/nvfs.cfg have been made.
Implications to file Characteristics:
"Change time" is no longer preserved:
On Linux/Unix systems, resetting the "access time" requires the "change time" of the file or directory to be set to the current time. NetVault normally uses the "change time" to store in the index and to decide if a file has changed when performing incremental backups. If the reset access times option is enabled, NetVault will use an item's "modify time" rather than its "change time" to store in the index and to decide whether to back a file up in an incremental. There are two disadvantages to this:
a) When a file's permissions, owner and, in future, ACL's are updated the operating system updates the "change time" but not the "modify time". Thus, when the reset-access-times option is selected, NetVault will miss changes in permissions, owner and, in future, ACL's when performing incremental backups. Files will be still be backed up correctly if the data is changed or the"modify time" is changed for some other reason.
b) Although the "access time" is now preserved and software sensitive to this time will be happy, the "change time" is no longer preserved and software sensitive to this time may not operate correctly. If the reset-access-times option is not selected, NetVault will operate as it always has i.e. The "change time" will be preserved and will be used for storage in the index and to check for changes to a file during an incremental backup.
Access time masking:
While a directory is being scanned or a file is being backed up, if a user accesses the file or directory at the same time as NetVault, NetVault will still reset the access time to the time it was at before NetVault accessed the file/directory. This has the effect of the access time stamp not reflecting a genuine user access of the file or directory.
Because of these implications, the functionality is not intended to be mainstream and is enabled by manually editing the nvfs.cfg.