[X4U] how long to clone drive?

[Eugene]

On Wed, May 12, 2010 at 04:09:23AM CDT, Simon Forster <simon-lists at ldml.com> wrote:
> 
> [1] RAID. I don't like RAID. In my experience it causes more trouble
> than its worth. It may work well in a server room but for small office
> / home office use it's just not robust enough. However, as everyone
> offers RAID (and no one seems to offer a simple 4 drive JBOD system) I
> bought a RAID box (2010-03-03). 35 days after installation the local
> electricity company cut the power. Twice. In short succession (a
> mislabelled busbar at the local substation). The RAID box reported
> that the RAID was fine - but the filesystem was hosed. Approx 2TB of
> data gone. (Engineers in Taiwan remotely accessed the box to confirm
> this).

Depends on the card and the specific configuration.  If you absolutely
need 24/7/365 uptime, at minimum implement a RAID 10 plus a hot spare.
And you MUST have an UPS as well as the monitoring software to detect
outages and initiate proper shutdowns.  That's just the RAID it is,
some things will never change.  :)

> You can argue that the RAID should have been on a UPS - and with the
> benefit of hindsight I'd agree. However, 5 other hard drives
> associated with a couple of different Macs all went through the same
> abuse (that discounts the laptop running at the time 'cause that's got
> a de facto UPS ;-). All five drives popped back up without any
> reported issue.

RAIDs deal with data reliability and increase data throughput.  It's not
about data backups in case of disk failure.  It solves specific problems
regarding fault tolerance, yet at the same time can be more prone to
failure because the implementation is less tolerant of other problems.

> Time and time again I've come across situations where RAID has caused
> the problem. Only use it for data you don't care about.
> 
> ;-)

I'm sure you forgot to sprinkle the pixie dust.


-- 
Eugene
http://www.coxar.pwp.blueyonder.co.uk/