Media Retention/Longevity?

I'm a new user of TrueImage and I am trying to develop a reasonable backup procedure for our data (home) and I would like to NOT use DVD's (too many problems with media reliability, slow etc.). I have read that DVD's have a 10+ year "life" (Wikipedia) but I'm having a hard time finding info on other media.

Is there reference info that specifies how long data can be stored/retained on various media (media longevity)?
- Hard disks
- DVD
- USB storage keys........
- Compact Flash/SD etc. cards
- other?

I have read some excellent threads on backup procedures etc.; however, I did not find any info on how long the backup/data is reliable (maybe I'm using the wrong search criteria).

Data retention/longevity would be an issue for especially for an off-site backup of archived data that might only be retrieved in the event of a disaster (e.g. fire).

Thanks, UncleWilley

 

While this is not an answer to your question, my comments are still relative.

Make a practice of recording the version number and build number on your TI Rescue CD's. Also keep these Rescue CD on a semi permanent basis. As long as you keep the backup, you should keep the Rescue CD related to that specific version. TI compatability is not guaranteed across multiple versions.

 

Your question is a good one. I have read that flash memory which includes USB keys, Compact Flash etc, are also around the 10 year mark. Hard-drives, I don't really know. I agree that optical media is not trustworthy.

The other problem is whether or not you can find a machine that still supports the particular device.

Personally, I do not back up data files with TI or anything else that uses a big container file. I would sooner backup the individual files in their native format for 2 reasons: 1: You don't need the program to recover the file - you still need whatever wrote it say XP for a .jpg but you do remove a layer of application. 2: If one file gets corrupted, one file is corrupted. With a container there is a chance a corruption in a bad spot will render the entire archive useless.

The most prudent thing is to re-write the archive at suitable intervals. At the computing center of the company where I used to work the staff were often re-tensioning magnetic tapes and doing read-checks and re-writes when necessary.

 

GroverH - excellent point on the necessity to retain the sw/Rescue CD as long as you keep data. In addition to noting the version/build # on the Rescue CD, it would help to write the same info on the archive data.

Seekforever - Using "native format" would certainly help reduce the need to retain old versions of sw/Rescue CDs. I plan to test "copying" native data to some dvds to see if I have any more luck than using the container files.

I recall a discussion in another forum on digital photo retention. There was a major case made to save digital photos in TIFF format vs. JPEG as TIFF is a more native format. JPEG files are typically created by specific sw pkgs that change over time!

Clearly the methods and procedures for backup/recovery can be complex. Maybe someone should write a book "Backup for Dummies".

Re-writing archived data periodically would reduce the need to retain multiple versions of the sw etc. Full image backups should be replaced/updated on a somewhat frequent basis. Not much help if you have data from a new pkg that isn't on your image backup.

I plan to post my finding regarding various media and data retention/longevity. Maybe a "sticky" or FAQ could be developed on the topic?

FYI I'm also searching in the club.cdfreaks.com forum that seems to have useful info on cd, dvd and flash memory etc.

 

Even though you reduce the "one bad container loses many files" problem, you still are dealing with a poor medium. The DIY disks are not the same as the commercial ones as you probably know. I'm sure they are getting better but I don't trust them especially RW types. A TV program I saw a while ago showed professional photographers putting HDs on the shelf as their archive media.

Perhaps. TIFF files I believe don't use any compression algorithm AFAIK.

I only image the OS partition (data files are copied to various locations) and if I didn't have a backup it wouldn't be the end of the world. I would just have to reinstall everything and that would just cause me a little time. OTOH, it would be a good refresher exercise and I'd get rid of a lot of junk I no longer use. It is the data files you create yourself and are available nowhere else at any price that you have to be concerned about doing the proper job on.

 

Regarding the OS partition and data files. I assume this means that you create multiple partitions on your HD, e.g. one for the OS and separate for data? That sounds like a good idea. Do you use the Acronis Disk Director Suite to create multiple partitions? Also is there a suggested min/recommended size for the OS partition (Windows XP)? I just installed a new 100GB HD in my laptop with 86GB for OS and data and the rest for Dell system recovery files etc.

 

Yes. IMO, bit mistake to mix the data with the OS and apps. There is no point in splitting the OS and the Applications up because they are too tightly connected. The data needs not to be on the same partition and when it is separate, you can blow away the OS at anytime for any reason without worrying about the data. I have my own data structure and I don't use My Documents on C for anything other than a scratch area. If you like using My Documents you can move it to another partition. My email is left on the server as a backup so I don't bother to move my email files.

I don't have Disk Director. I set up the partitions before I loaded the OS and apps. However, partitioning software would do the job.

Minimum size varies but for me 20GB is more than enough for my XP and apps.

Another trick, if you wish to minimize the size of C so you can image and restore faster for testing new software purposes (Restoring an image is the perfect rollback when testing), is to load any large games like Flight Simulator etc onto its own partition. This does somewhat violate keeping the apps with the OS but these game files are large and rarely, if ever, change. You can make up one image of the games partition and you don't have to worry about it until you install another game.

 

Hope you don't mind another question regarding backing up of individual files. Do you just copy/drag&drop the files to your backup media or do you use a special package? Is there a method to validate the copy via "XP"?

 

No problem.

I am not aware of a method to validate after copying in XP using Explorer.

I don't copy the files for backup since I want it to run automatically. My data files are on a machine that runs all the time and "copying" is scheduled to run in the middle of the night each day.

To enable this I use Syncback which performs the scheduling, which files and folders to do, new files/changed files, etc. I have the paid version ($30US for up to 5 personal use computers) which also permits versioning - avoids writing a later file you made mistakes in over the backup and turning it into a dud. Syncback isn't the only program out there you can Google "replication" and similar terms. Syncback allows you to setup verification in the profile but they caution that it slows it down by 3X or so should that be an issue. I haven't turned this on but I might.

The above copies the files to a second internal HD every night. Every month or when I think I should if I've done some work that would be a real PITA to have to repeat I copy the backups to a USB drive. I actually have 2 that I rotate. I also leave the old backups on the drive until there is no room and then I clean enough off. Never, ever just keep the lastest backup.

That is 2 levels of backup. For a third level I write to DVD about 1-2 times per year. It is diversity of media but is becoming a bit tedious due to the amount of data now that I have some large audio files, more pictures, etc. The DVD backups are kept at a friend's house for total disaster recovery - somebody steals everything or the house burns to the ground. Note that the retention time of these DVDs as far as needing to read the data is only about 6-12 months then they are replaced with a complete newer set.

I am thinking of abandoning the diversity of media and just writing everything to a HD and giving it to him to keep.

Another safe place to keep a small number of files, such as my spreadsheet I would really hate to lose, is on personal webspace that you have or you can email it to yourself using Hotmail, Google mail or whatever and leave it on the mail server. You can may also be able to do this mail method with your ISP's mail system if it allows leave on server and the space restrictions aren't too tight.

This is how I backup my email BTW, I have 2GB of mail space provided by my ISP and I leave copies on the server. I have to go in and clean it up every now and then though.

That's what I do. There may be places where it could be better but I'm satisified it is adequate.

 

It makes a big diff what kind of CD or DVD media you use. If it's commercial processed, then the data is pressed and the longevitiy is probably as long as you can get in any medium. Ten years would be, imo, a safe bet. Ones that you write with your PC use a light-sensitive to mark data bits and the dye does not have the stability of a physically pressed mark. Five years if probably a safe bet with high quality write-once CDs and DVDs. Rewriteables have less stabile dyes and while one might be good for as many as ten years, two years is probably the safe bet.

The quality of CDs and DVDs, commercially impressed and user written varies widely. While there are only a few manufacturers of disks, there are dozens upon dozens of brands -- all the disks coming from the few manufacturers. So, it's really hard to tell the quality of a given branded disk. IF you need to archive for a short time, cheap disks are a reasonable choice. If you need to archive for along time, it's wise to by disks that you know are high quality, even though they will undoubtedly cost more.

At the extreme, really high quality, archive quality CDs and DVDs cost many times more than run of the mill disks.

Generally, all for the same holds for magnetic media with the added complication that the electronics, or mechanics might fail with age. I wouldn't rely on a Hard for archive purposes for more than 5 years of non-use or more than one year in-use.

Multiple backups greatly increase your chances of retrival because even items of the very same physical type are unlikely to fail at the very same moment.

 

A couple of thoughts regarding backing up individual files, this is what I do:

My system:
Three internal PATA drives (C:, D: and E and one USB drive (F.
Select folders on the C: drive that you want to back up. Create new ones if you wish. In my case I back up the My Documents folder as well as several personal folders. Then I do two things:

1. Create a shortcut to the desired destination drive(s) and put it in the ‘Send To’ folder. With this in place I can select a file on the C: drive and right-click it selecting the destination drive.
2. For an automated approach to transferring the selected folders that I have defined, I have written a batch file that over-writes (deletes the old) existing folders with the same name on the destination drive and replaces them with the later version. Since this is done manually I have full control.

An example of the text for my batch file is this:

ECHO OFF
echo Preparing for the copy to drive D:, please wait...

RMDIR /S /Q "D:\1_Personal Batch File (Copy)"
RMDIR /S /Q "D:\My Documents (Copy)"
RMDIR /S /Q "D:\Kodak Pictures (Copy)"

XCOPY "C:\1_Personal Batch File" "D:\1_Personal Batch File (Copy)" /E /I /H
XCOPY "C:\Documents and Settings\[User Name]\My Documents" "D:\My Documents (Copy)" /E /I /H
XCOPY "C:\Documents and Settings\All Users\Documents\My Pictures\Kodak Pictures" "D:\Kodak Pictures (Copy)" /E /I /H
EXIT

I know of no way to validate these transfers in Windows XP.