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Date: Wed, 11 Jun 2008 20:35:08 +0200 (CEST)
From: Wojciech Puchar <wojtek@wojtek.tensor.gdynia.pl>
To: freebsd-questions@freebsd.org
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Subject: Re: FreeBSD + ZFS on a production server?
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> Wojciech Puchar wrote:
> > 3) a CPU,cache and memory bandwidth hogging "feature" of checksumming all
> > blocks. thing that are already done in disk hardware. fortunately you can
> > turn this off
>
> Obviously you have been lucky to never be a victim of
> silent disk corruption (or you just haven't noticed).

what you mean. that disk wrote the data wrong and doesn't detect it on 
read? i would mean broken disk processor, it's memory etc.

possible - as much as broken main processor, main memory, some of chips on 
motherboard etc. - which will make ZFS calculate checksum wrong on write, 
or even calculate checksum right of wrong data generated by badly 
operating programs.

given the complexity of motherboard+CPU etc. to complexity of disk 
hardware, i don't think "silent disk failure" happens often.

i think all your cases wasn't disk, but general hardware problems.
ZFS may help detect it, or it may not. if it helped for you.

even without ZFS it WOULD cause problems with programs like random 
crashes.


personally i often got disk failing the way that it was unable to read or 
write giving an error, but never things like that.

> You're free to use UFS, of course, and keep suffering
> from its shortcomings.

i have to start suffering at first....