Re: IBM in talks to buy Sun

From:

Eric Sosman <Eric.Sosman@sun.com>

Newsgroups:

comp.lang.java.programmer

Date:

Fri, 20 Mar 2009 11:25:28 -0400

Message-ID:

<1237562686.432896@news1nwk>

Lew wrote:

The notion that you can simply hot-swap disks if they fail in a high-
volumn production environment is wacky.

The notion of hot-swapping failed disks is certainly not wacky.
Perhaps it's the "simply" that you consider wacky? That might
make sense.

It's not just data, it's service time that's valuable. Most such
installations cannot afford downtime, at least not much. Disk
failures are a major fubar. The motivation for RAID itself proves
that - it increases the cost per storage amount in favor of higher
reliability.

Right. And a RAID unit that survives a disk failure but still
must be taken out of service for repair is less reliable than one
in which you can replace the failed drive without interruption.

The suggestion that one can buy inferior hardware in quantity and just
swap in new pieces when something breaks betrays an utter lack of
understanding of the problem. If that idea worked, the people
responsible for those data centers would do that, but it doesn't and
they don't.

Tradeoffs certainly exist. It is not a given that the same trade
makes sense for all circumstances.

--
Eric.Sosman@sun.com