Re: Building a file server - advice please

Nico Kadel-Garcia wrote (in part):

> That's what RAID5 does. That way, if one drive fails, you can keep going for
> a while until you can replace the drive. And with 4 drives, your odds of a
> single drive failing go way, way, way up.
>
Do I misunderstand you, or did you say it ambiguously?

With 5 drives, the odds of a single drive failing _remain the same_; i.e.,
connecting up 5 drives in a RAID5 system does not affect the Mean Time To
Failure of a drive in any way (unless the box is improperly cooled or the
power supply overloaded). The perceived failure rate of a single drive may
go up slightly because of the failure rate of the RAID controller, but that
should be very small since the controller has no moving parts, so the
failure rate of the connectors and cables probably dominates this.

The odds of the entire system failing presumably go down, which is an
important reason to use a RAID system. I do not know the details of one
level of RAID from another, but if it is true that RAID 5 can tolerate one
drive failing and still work, the odds of a system failure with 5 drives in
there would be 1/5 those of using a single drive.

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