Re: hardware raid solutions?

ubuntu@xxxxxx wrote:

Is it just me, or does ZFS just sound too good to be true?

From the opensolaris site:

"What is ZFS?

ZFS is a new kind of filesystem that provides simple administration,
transactional semantics, end-to-end data integrity, and immense
scalability. ZFS is not an incremental improvement to existing
technology; it is a fundamentally new approach to data management. We've
blown away 20 years of obsolete assumptions, eliminated complexity at
the source, and created a storage system that's actually a pleasure to use."

Doesn't that just sound like a scam? I keep waiting to hear what the
downside is... or maybe I've just been in this business too long and
have gotten burned too many times...


yes, on one hand it does sound like a scam. At the same time, many of the things we have in our lives would sound like scams to people 20 years ago. Hell, the fact that I am talking to the computer and it is recognizing accurately 19 words of the 20 would sound like a scam even 15 years ago.

as for all the code size, speed, etc. etc. claims, ZFS fits with what I know is possible. I've worked on filesystems and some of the things they have solved were questions I was asking 10+ years ago. Such as what happens if you consider your disk storage a heap and start aggregating physical disks under that heap. I never quite got the naming problem but it looks like they have come up with a good solution. The copy on right tricks make a lot of sense and are very simple to implement.

Do they really get better performance? We don't know but unlike most snake oil, we can test it. That's the joy of open source. You don't have to question, you can try it out.

I will admit to a bit of sensitivity to random doubting claims coming over mailing lists. I've developed some anti-spam techniques[1] in the past which got shot down, not because it wasn't any good but because the people making comments were too lazy to do the math. It wasn't until much later that I built the model myself and showed had they were off by at least a couple orders of magnitude on the effects of the system.

there was even one paper on this technique showing how the core assumptions were "wrong" but when I presented a counter model, the paper originators were amazingly silent.

so I ask you to be careful and measured in your doubt without examination of the code or system. Real or not real, without trying and modeling, you can't tell. If you have some facts, then it's OK to throw stones. :-)

--- eric

[1] python knowledgeable help wanted. Job descriptions available on request.


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