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From: Wojciech Puchar <wojtek@wojtek.tensor.gdynia.pl>
To: Daniel Feenberg <feenberg@nber.org>
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Cc: Kaya Saman <kayasaman@gmail.com>, freebsd-questions@freebsd.org,
	Oscar Hodgson <oscar.hodgson@gmail.com>
Subject: Re: Anyone using freebsd ZFS for large storage servers?
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> As for ZFS being dangerous, we have a score of drive-years with no loss of 
> data. The lack of fsck is considered in this intelligently written piece

you are just lucky.

before i would start using anything new in such important part as 
filesystem, i do extreme test, ssimulate hardware faults, random 
overwrites etc.

I did it for ZFS not once, and it fails miserably ending with 
unrecoverable filesystem that - at best - is without data in some 
subdirectory. at worst - that crashes at mount and are inaccessible 
forever.

under FFS the worst thing i can get is loss of overwritten data only. 
overwritten inode - lost file. overwrite data blocks - overwritten files. 
nothing more!


what i don't talk about is ZFS performance which is just terribly bad, 
except some few special cases when it is slightly faster than 
UFS+softupdates.

It is even worse with RAID-5 style layout which ZFS do "better" with 
RAID-Z.

Better=random read performance of single drive.