[Leaplist] Backup to external USB md RAID 1/5?

[Jason Boxman]

> Jason Boxman wrote:
>> To save physical space, I am considering eliminating my backup
>> server entirely.  Instead, I am considering replacing it with three
>> external 3.5" (the current internal disks) drives in a RAID 1 or 5
>> configuration.
>
> Okay, I'm scratching my head.  What size is your current "backup
> server"?

It's larger in physical size than zero.  I have five boxes and when it's
time to move, it's five too many.

Not having any money, several systems I acquired for free.  The backup
server is a huge, ancient full tower system.  It's an inch taller than my
HX700B full tower, but with one less 5.25" bay.  It has an old Dell P3
500MHz slot 1 CPU mainboard, so I doubt it'll fit in a Slim or Cube case.

> In my house, anything with four (4) 3.5" HDs or less is MicroATX or
> smaller.  That means any one (1) of three (3) common form-factors ...
> - Tower:   7" x 14" x 15" (holds 5 x 3.5", 3 x 5.25")
> -  Cube:   9" x 11" x 14" (holds 3 x 3.5", 2 x 5.25")
> -  Slim: 5.5" x 12" x 12" (holds 3 x 3.5", 1 x 5.25")
>
> While there are "Slimmer" designs, but they don't take full height PCI
> cards.
>
> That Slim is not really much bigger than three (3) 1.75" x 6" x 8"
> external 3.5" drives stacked to 5.5" x 6" x 8".  I don't see this being
> about size, but that's just me -- I've been doing MicroATX for 4 years.

Wouldn't be if I owned a mainboard of that form factor and a Slim case.

>> Can you run md RAID against a bunch of external USB 2.0 drives?
>
> Of course!  Of course, you'll also have ...
> - Disconnections (even Apple admitted this back in 2003 with FireWire)
> - Disconnections causing "broken" mirrors/stripes (especially w/MD)
> - Shock issues (3.5" is not designed for mobile, 2.5" is)
> - Systems not liking the "unknown" format (may I "initialize" for you?)
> - Piss-poor performance (forget anything faster than 20MBps w/USB 2.0)
> - Etc...

Meh.  That's what I suspected.

<snip>
>> (If the system itself dies and I need access to the backups,
>> not to move the hard disks off-site;
>
> Why not just have extra internal storage in your main system (extra
> copies -- maybe revisions of files stored in a different filesystem in a
> Subversion repository), and then the backup server (sync your Subversion
> repository to it, maybe a "drop area" for really important stuff), and
> then maybe an external 2.5" disk for the most critical stuff (sync that
> "drop area" to it) that you plug in and unplug regularly (maybe keep
> with you in your backpack wherever you go), and call it a day?

How much extra?  I use Dirvish and need at least 1:1.  I've done fun
things like accidently `rsync --delete` against a filesystem with an NFS
mount and had to recover most of my files from backup.  I enjoy having a
full backup on-line and available.

> I think it covers most everything for a home user.  I know it does me.
> I sync my main server against my main desktop, and vice-versa, and then
> use DVD-R/RAM and 2.5" drives for off-line/off-site.

I suppose I could do that.  Only a few years ago, I was still dual booting
my workstation, so that would've been more of a pain.

> I've never seen "size" or "reliability" argued against a backup server.
> Interesting.  I mean, if your "backup server goes down," what does that
> cost you?  It's secondary.  But if external drives are bringing down
> your main system, that's primary.  ;)

I've lost my backup server (was RAID-0 as I couldn't yet afford another
300GB ATA disk for RAID-5) and my single SCSI 18GB SCA OS drive on the
file server almost simultaneously.  I like reliable backups.

So, no, I won't be switching to using USB2'd drives, ever.  I just thought
I'd ask.

My true goal is simply to reduce footprint.  However, I happen to have all
these existing systems.  Other than physical size, they all work fine.  I
can't afford to replace them with a bunch of MicroATX based systems today,
since that'll probably cost more than $0.

In the future, once the equipment is sufficiently old to justify
replacement, I think I favor the Micro-ATX mainboards and cube cases.

I'd also like to reduce the number of hard disk drives, but the ones I
have work fine.  The 4x120GB WDs have lasted for years.  My 2x120GB and
3x300GB Seagate drivers are all still under the five year warranty for at
least 3 years each.

So I am kind of stuck unless I want to stop using perfectly good equipment
and spend more money to replace it all with smaller mainboards and cases
and fewer, larger hard drives.

Sigh.