Re: What is difference between zfs and ufs?

On 2026-08-17 15:37, Wojciech Puchar wrote:
>>> The only case that you may lose lot of data is that your disk fail 
>>> completely and is not mirrored or in other RAID protection.
>> 
>> 
>> Unless something has changed fairly recently, to my knowledge UFS does 
>> not have any explicit mechanism for combating silent data corruption.  
>> This is different to ZFS, which, unless you disable it, explicitly 
>> does.
> SATA/SAS interface have checksums. Disk drives store data with error 
> correcting codes.
> 
> Why add useless feature that just generates CPU load and memory 
> traffic.
> 
> I have never heard about "silent data corruption" you described to be 
> real problem anywhere. hardware does protect from it very well.
> 
> This ZFS feature like many others is nothing more than marketing.
> By the way i've personally seen ZFS total failures with completely 
> intact disks

I have actually experienced silent data corruption myself, several times 
over the last couple decades. In one case, it was a memory corruption 
issue by a driver in FreeBSD with a HiPoint controller. Thankfully I 
still had another copy of the data, but ZFS would have alerted me much 
sooner. Checksums are definitely not just a marketing feature.

This was with consumer grade hardware admittedly, not server grade. Not 
all of us can afford server grade hardware for personal data though.

--
Jonathan