classiccmp server hardware

[Fred N. van Kempen]

On Mon, 11 Oct 2004, Jochen Kunz wrote:

> You have to by two RAID controllers if you wane be real save. You need a
> spare in case the RAID controler fails. The RAID controler is a single
> point of failure!
They call that controller duplexing.  Separate controllers, active,
preferrably on separate buses.

> It depends on the load that the server already has and how much overhead
> software RAID1 causes. Typically RAID1 doesn't cost that much CPU. To
> the past - present comparision: CPUs got a _lot_ more faster then disk
> dirves in the past 20 years. See the thoughts behind the BSD LFS.
I have never trusted OS-level disk redundancy schemes, and never
will.  Promise controllers have strange ways of doing things, and
most certainly do require OS-level software assistance.  Disks
attached to a Promise RAID1 controller can be taken off the Promise,
and attached to a regular IDE port, and will work as-is.  Typical
RAID controllers that do hardware-supported RAID store state and
config info on the attached drives, so they usually claim a few
sectors for that.

Cheers,

--fred (happily using SAN, Compaq RAID and InforTrend IDE RAID.)