Backup to Thumb Drive

[Stephen]

The issue with USB Flash drives is they have a terminal Number of
writes before they are done.

With a USB HDD you have the nromal life expectancy of a HDD and i
think in the long run it is a better idea.

However Aside form that issue and the dangers of Cheap flash memory it
should work just fine.

On Mon, Nov 3, 2008 at 9:22 AM, Alan Dayley <alandd at consultpros.com> wrote:
> On Mon, Nov 3, 2008 at 8:16 AM, Dan Lund <situationalawareness at gmail.com> wrote:
>> I'd definitely have to side with the external hard drive scenario.
>> While USB thumbdrives are real nice for the size they have a limited
>> lifespan and can lose data much easier than a hard drive from
>> electromagnetic interference.
>>
>> I still prefer Linus Torvalds' quote, "Only wimps use tape backup:
>> _real_ men just upload their important stuff on ftp, and let the rest
>> of the world mirror it ;)"
>> lol
>>
>> Thanks,
>> Dan Lund
>
> Flash is LESS susseptible to electromagnetic interference than hard
> disk drives.  I have personally tested degaussing coils that
> successfully erased hard drives but did nothing to flash storage
> drives.  This is because hard disk drives use magnitism to store data
> while flash uses capacitance, essentially.
>
> Data retention of flash is at least 5 years and some manufacturers
> state retention times much longer than that.  Sitting in a safe
> deposit box enviornment, flash should not lose data.
>
> But, it all depends.  ;^)
>
> There are, generally, two types of flash: multi-level cell (MLC) and
> single-level cell (SLC).  MLC can store two or more bits in a single
> flash cell while SLC stores one bit per cel.  Most consumer flash
> drives use MLC flash because it is MUCH cheaper than SLC.  But,
> becuase of the mult-bit (read: multiple voltage level) nature of MLC,
> it is far less data reliable than SLC.
>
> The rub is that there is not an easy way to find out if the flash
> device you have is MLC or SLC except by price.  SLC will be quite a
> bit more expensive.  SLC is also sold under a description of
> "industrial" or "high reliability" and such terms.  If what you have
> was a good consumer price and does not have such terms attached to it,
> it's MLC almost for sure.  This is not to say that MLC is all bad.  It
> works well for situations like storing photos or operations where lots
> of rewriting does not take place, like backups.  ;^)
>
> Just remember, with flash media you DO get what you pay for.  Buy a
> well known brand link San Disk, Lexar, STech, Samsung, Toshiba, etc.
> to get the highest quality possible.  Don't skimp on price, especially
> for data backup.  The "off brands" do buy up low quality or even
> rejected flash for use.  This is usually not a big problem because if
> a bit flips in one of 8 mega pixels of a photo, would you know it?
> But if a bit flips in your ext2 filesystem inode tree, you may have
> just lost something!
>
> I would have no problem depending on flash to store backups as long as
> I used the best quality drives I could find.  And they were in a
> resonable refresh schedule like one would with tapes or hard drives
> anyway.
>
> Check Sam's Club.  They regularly have Toshiba USB sticks and other
> flash media on sale for the price of bargan brands elsewhere.  They
> are good quality, in my experience.
>
> I love Linus' backup method too.  But I'm no Linus Torvalds so must
> use other methods.
>
> Alan
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-- 
A mouse trap, placed on top of your alarm clock, will prevent you from
rolling over and going back to sleep after you hit the snooze button.

Stephen