Asure is a simple tool for computing and checking file integrity. Its function is similar to something like tripwire, but its intended use it quite different. I run this on each volume before a backup, and can use it on a test restore to verify that the backup was made properly.
asure {signoff|show|scan|update|nothing|copy|check}
Initially, you will need to run "asure scan" at the top of a particular directory. This will generate a file 0sure.dat.gz in that directory containing stat and fingerprint information for all of the files in that tree (excluding mountpoints).
Later, you can run "asure check" to compare the contents of the directory with the scan file. Asure does not check inode numbers or ctimes so can be successfully run on a restored backup.
It is possible to rerun the scan to generate a new scan. This will move the old scan to 0sure.bak.gz (deleting the previous backup). This will recompute the fingerprints of all files in the directory.
As a special optimization "asure update" can be used to rescan a directory, but use fingerprint information from the previous scan. Any files with the same path, and stat information will not be re-hashed. This can be significantly faster. Although it doesn't re-read the data and will miss disk corruption, it will still be useful to verify backups.
The last command is "asure signoff". This works kind of like check except it doesn't compare the tree, it compares the 0sure.dat.gz file against the 0sure.bak.gz file. Running "asure update" (or a scan) followed by a signoff will give the same output as running a check, except that the new fingerprint information is kept.
This page last modified 2008/01/03.