[plug] RAID-1 vs rsync vs ? for high availability

[levsky at rave.iinet.net.au]

On Fri, Dec 06, 2002 at 10:56:21PM +0800, Denis Brown wrote:
> The RAID HOWTO points me in the direction of RAID-1 and by using
> persistent superblocks would mean that I can boot off the array.
> Assuming "sensible" failure conditions RAID-1 looks to have good data
> integrity chances.

RAID-1 is cool, but you take quite a performance hit on writes.
Plus, it's *really* wasteful on disk resources.  I'm fond of RAID-5 
personally, if implemented with a decent hardware raid controller.
Just depends on what you're doing I suppose - If you're just mirroring
your system drive, then RAID-1 is likely to be more than adequate.
If you're trying to store lots of data, it's probably not.

> The primary application is a groupware server and while it would be nice 
> to have redundant boxes, etc that might not be possible in the early days
> of the project -- I'm wanting a toe-in-the-door to strut some Linux stuff.
> I have omitted the obvious aspects such as choosing a high quality mobo,
> adequate psu, not overclocking the cpu, running the show from a ups...
> 
> Thoughts would be appreciated :-)

If you're planning to have more than about half a gig of ram in your
machine, some form of ECC is a must.  With standard bit error rates
what they are, your probability of having some ram bit errors over 
a couple of months is very high.

Really - as you've already intimated, the best solution is to have 
redundant boxes.

-- 
Do not look into laser with remaining eye.