Backup cycle

[JohnA]

Hi,

 

 

 

I've set up an Easyscript session to backup my system... it uses two Backup sets. I've modified the script slightly so that it backs up M-Sat normally, and Sunday as a separate item - every other week. What I'm wondering is what is the best way of doing this:

 

 

 

1) I just switched to Backup Set B - Backup Set A has about 2G out of 10G left

 

2) After this week finishes, I will revert back to Backup Set A

 

 

 

Is it better to just keep going and add to Backup Set A until the tape fills. It it fills, should I just add another tape? Or am I better off recyling the same tape over. (I have another tapes for 2 tapes/set.

 

 

 

Any input would be appreciated.

 

 

 

Thanks,

 

John

[AmyJ]

The answer would be based on how much historical data you went. In most cases, more is better. If you never plan on needing more then a week of historical data (2 weeks between both sets) then recycle will work best for you. If you need historical data for potenially months, you may want to consider manually recycling when the tape fills or schedule periodic recycles in your script (every 6 weeks for example). If you go this route, be sure to stagger the recycle dates so that both sets don't recycle at the same time - in other words, don't empty both your sets at the same time. Provide space in-between to allow for longer retention of data.

[JohnA]

Hi,

 

 

 

What about wear and tear on tapes? Doesn't two sets with one tape each means that it gets written more often than two sets with two tapes? The second tape will probably consist of many many small backups because of the incremental changes recorded and will last a long time. But I wonder how hard it will be to restore from such a set if the need arises...

 

 

 

Thanks for your input, I appreciate it.

 

 

 

Take care,

 

John

[AmyJ]

Media life totally depends upon how the media is stored and taken care of. To help maintain maximum media integrity, we would like to offer the following tips:

 

 

 

1) Avoid temperature extremes. Storing backup media (of any type) in a car can expose the media to extreme cold or heat depending on the time of day. The temperature in a car over a year can easily range from 20° to 127 °F.

 

 

 

2) Magnetic media's worst enemy is moisture/humidity. If tapes get wet or moist, or are stored in a very humid environment, they deteriorate. Consistent humidity is important. 50% relative humidity is ideal.

 

 

 

3) Particulate Contamination also compromises your backup media. Media stored in a dusty or dirty environment (like a factory or warehouse) can damage tapes (or increase the chance of scratches in CD-R media).

 

 

 

Storing backup media in a fire-proof safe in a climate controlled building is always better than keeping something in your desk drawer at home (especially if that desk gets hit by sunlight each day, etc.)

 

 

 

4) We have heard stories of problems with EMF causing problems for tapes. One tape vendor told a story about a user who stored his DAT tapes in his briefcase along with his Cell phone. Exposure to the Cell phone (in standby and ringing from time to time) was suspected as a cause for data integrity problems with his backup tapes. This could be an urban legend but it is better to be safe then sorry later.

 

 

 

Dantz is committed to making sure that not only can users back up data, but they are able to restore that data years later.

[JohnA]

Hi,

 

 

 

So you are saying that one can write over media pretty much indefinitely? I thought I read somewhere that some tape media (e.g. Travan-5, DAT) had a life expectency of about 100 writes - after a while, the lubrication in the tapes is gone causing tape errors. Is this not true? If this is true, a typical backup tape won't last more than a year or two if it is constantly being written and rewritten, no?

 

 

 

Take care,

 

John

[AmyJ]

In reply to:

---

So you are saying that one can write over media pretty much indefinitely?

---

No, media does have an expected lifespan. Sorry I was unclear on that one. Repeated use of tapes will degrade the tape and ultimately require replacement. However, there are other factors which can cause the tapes to fail sooner then expected. We try not to use a tape for more then a year or so. However, length of time in use can be dependent on how often a tape is used. For example, someone using the same tape day after day will replace the tape more often then someone cycling a tape weekly, monthly, etc. It's best to take the advertised life span with a grain of salt - best case scenario is always going to be advertised.

[JohnA]

Hi Amy,

 

 

 

Thanks for your reply. One more question if I may... then does it make sense to alternate between 2 backup sets each consisting of 2 tapes? Or does the extra tape in each set make any restore that much harder (might have to scan two entire tapes to perform a restore).

 

 

 

Thanks for your patience, I appreciate it.

 

 

 

Take care,

 

John