{"id":25378,"date":"2014-06-30T09:00:15","date_gmt":"2014-06-30T14:00:15","guid":{"rendered":"https:\/\/eshop.macsales.com\/blog\/?p=25378"},"modified":"2014-06-30T13:34:56","modified_gmt":"2014-06-30T18:34:56","slug":"validating-data-integrity-key-when-backing-up-archiving","status":"publish","type":"post","link":"https:\/\/eshop.macsales.com\/blog\/25378-validating-data-integrity-key-when-backing-up-archiving\/","title":{"rendered":"Validating Data Integrity Key When Backing Up, Archiving"},"content":{"rendered":"

\"OWC\"By Lloyd Chambers, Guest Blogger<\/strong><\/p>\n

An overlooked aspect of data management is\u00a0data integrity<\/strong>: are the files intact tomorrow, a year from now, on the original drive<\/a> and backup drives<\/a>, or perhaps even on a DVD or Blu-ray<\/a>? Or after having been transferred across a network?<\/p>\n

Knowing that files\/data are intact with no damage is a key part of any system restoration\/update\/backup\/archiving. In some situations it could be mandatory (record keeping).\u00a0The more valuable the data, the more important it is to consider the risks to loss, which include loss by file corruption as well file deletion<\/span>\u00a0\u2013 not to mention viruses and software bugs and user errors.<\/p>\n

\u201cData\u201d can mean image files (JPEG, TIF, PSD\/PSB, etc), video clips or projects, Lightroom catalogs, etc. Or it could mean spreadsheets, word processing files, accounting data, and so on. Knowing that these files are 100 percent intact leads to a comfort level in making system changes in storage approaches.<\/p>\n

How can data be damaged? Disk errors, software bugs in applications or drivers or the system itself can happen. Moreover, the \u201cdamage\u201d could be user-induced: saving over or replacing\/deleting a file inadvertently. Simply having a \u201cwarning flag\u201d could be useful in noting that \u201cno expected changes\u201d is violated.<\/p>\n

For example<\/strong>, suppose that a new computer system is acquired and various drives need to be transferred over. Or that you have upgraded to a newer and larger hard drive. Or\u00a0swapped SSDs<\/a>. Or there is a need to restore from a backup. Or that you burned files to a DVD or Blu-ray \u2013 are they intact with no changes? Even RAID 5<\/a> with its parity data does not validate files when\u00a0reading\u00a0them, and a validate pass is over the entire volume with no selectivity for the desired files.<\/p>\n

Enter\u00a0IntegrityChecker, part of\u00a0diglloydTools<\/a>.\u00a0At any time, files of any and all types can be checked against a previously computed \u201chash\u201d, a cryptographic number unique to the file. If there is a mismatch, the file has been altered, somehow. This check can be made at any time: on the original, or on a 1,000th-generation copy of that file. The only requirement is that the hash be computed once and remain in the same folder as the file for later reference.<\/p>\n

How it works with IntegrityChecker<\/strong>
\nIntegrityChecker\u00a0computes a SHA1 cryptographic hash for each file in a folder, storing those hash numbers in a hidden \u201c.ic\u201d file within that folder. Thus, all files in the folder have a \u201chash value\u201d against which its current state can be checked.<\/p>\n

The process can be run on folders, or an entire volume.<\/p>\n