Originally Posted By: Dignan
I know you're using a drive for backup, but I'd also recommend using an online backup service like Mozy or Carbonite.

The fly in the ointment there is "online". Perhaps I don't understand how it works, so if I'm wrong here, please tell me.

Let's say I have 1.5 TB of data to back up. That comes to 12 Tb (Tera-bits) of data: 1,649,267,441,664 of data that I would have to upload at a rate of 1.84 Mb/sec (see attached photo), or to make the math a bit less confusing, at 1,929,380 bits per second (1024 bits/kilobit, 1024 kilobits/megabit). That would take 854,817 seconds, or 237 hours, or roughly 10 days of continuous uploading. Assuming my upload speed remains constant (I have seen it as high as 1.98 Mb/sec, as low as .37) and assuming my internet connection even remains connected for 10 straight days which in my experience (this is Mexico!) would be unprecedented. I suppose the trick would be to do it piecemeal, a couple of hours a day, in which case the backup would take about four months to complete.

My 6 Mb/sec download speed is the envy of all my friends and neighbors here, and is the fastest and most expensive internet connection available in this part of Mexico. (I think it costs me about $50 USD/month, but that includes cable television which I don't watch. Ever.) It is not, however, reliable. At the provider's request I am now keeping a log of the status of my cable modem at the time of the outages.

And to digress even further... There must be something fundamental about RAID arrays that escapes me. If I understand correctly (and I probably don't) if a hard drive in a RAID fails, you just replace the bad drive and the RAID controller rebuilds the data... unless a second drive fails before the rebuild is completed, at which point all the data in the array is lost. That seems pretty scary to me. I feel much safer having my data duplicated on a separate external hard drive. Even if my computer catches on fire I will still have my backup. Another thing I don't care for with RAID is if I do something stupid and mistakenly change a file (I did that on a very important, very large Excel file - left a column out of a sort and then saved the file) that file is changed in your RAID and there's no going back. My backup may be a few days out of date, but at least I still have the original file.

Probably I'm blowing smoke here, because a lot of people who know a whole lot more about computers than I ever will know swear by RAID systems,. I probably just don't understand them.

Your point about losing the data through theft, though, gives me pause. Crimes against persons where I live are very rare. Crimes against property is another matter. OK, you've convinced me. I won't do the on-line backup, but I am going to start putting my external backup drive in a hidden storage place where I keep my valuable papers (passport, FM3 visa, etc.)

Thank you for bringing that thought to my attention.

tanstaafl.


Attachments
SpeedTest.jpg


_________________________
"There Ain't No Such Thing As A Free Lunch"