[GTALUG] Portable Backup Drive Compatible with Linux (and Recommended Backup Software)

[D. Hugh Redelmeier]

| From: Jason Shaw via talk <talk at gtalug.org>

| I personally like the form factor of Western Digital Passport drives as
| they are USB powered,  USB 3, and small form factor.  I get decent
| performance out of it, and so long as your backups are incremental, after
| the initial sync, the future changesets should be fairly small.

Thoughts about external drives:

- FireWire is gone.  Let that be a lesson.

- eSATA is probably going to disappear.  It isn't common.  For
  longevity, pick USB 3.

- eSATA has a couple of advantages and disadvantages
  + faster than USB2 (important for older computers)
  + makes S.M.A.R.T. features of the drive available to the computer.
  - hot-plug is very system-dependant and not well documented.

- 2.5" is so much more convenient than 3.5
  + one cable vs separate data and power cable
  + no power supply brick
  + physically smaller
  + bare drives are meant to survive physical shock better
    (laptops need more robust drives than desktops)

- the price difference between 2.5" and 3.5" isn't bad

- external drives are usually cheaper than bare drives!  Very odd.

- you should size your drives appropriately for your workflow
  Seagate 4T 2.5" drives are amazingly inexpensive once in a while
  (I've collected a few at ~$125 + tax).  But a lot of eggs fit in
  that basket.

- WD external drives are encrypted.  You cannot take the drive out of a 
  busted enclosure to recover the data.  Seagate drives are can be taken 
  out of the enclosure and read (at least until recently; any changes are 
  unlikely to be announced).  The reason WD does this is probably to 
  maintain the price premium for bare drives.  It makes a small number of 
  failure modes worse for WD drives than Seagate drives.

- I've bought a few inexpensive NAS boxes.  Very convenient but the
  firmware gets obsolete and security might be a problem.  They seem
  fairly slow.

- USB flash memory sticks are very convenient but their reliability
  seems unpredictable and bad.

- assume that all drives fail.  If all your drives are of one model,
  they may all fail the same way at roughly the same time.  But most
  backup plans assume that each failure is independent.  OOPS.

- consider using archival CDs or DVDs as a supplement to hard drives.
  Mag Tape seems to be a gonner.

- low-acid paper is pretty useful but only for low-volume archiving.
  Even more so for clay tablets.

- the only safe archival plan involves regular copying of the data.
  Copying must include verifying.  "Regular" means at a frequency
  significantly higher than the expected failure rate of the medium
  (obsolescence is a kind of failure).  This copying should be
  scheduled when the previous copy is made to increase the chances
  that it will actually happen.  Discipline!  This is something I have
  failed at too often in my half century of playing with computers.

- pick you filesystem carefully
  - some may become obsolete
  - some try to survive limited medium errors

- archived data needs to be indexed in some way that it can be found.
  It must be in a format that will be accessible when it is needed.
  This is a big topic.