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Date: Fri, 14 Mar 2014 13:15:22 -0600 (MDT)
From: Warren Block <wblock@wonkity.com>
To: Ian Lepore <ian@FreeBSD.org>
Subject: Re: GSoC proposition: multiplatform UFS2 driver
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On Fri, 14 Mar 2014, Ian Lepore wrote:

> On Fri, 2014-03-14 at 15:27 +0000, RW wrote:
>> On Thu, 13 Mar 2014 18:22:10 -0800
>> Dieter BSD wrote:
>>
>>> Julio writes,
>>>> That being said, I do not like the idea of using NetBSD's UFS2
>>>> code. It lacks Soft-Updates, which I consider to make FreeBSD UFS2
>>>> second only to ZFS in desirability.
>>>
>>> FFS has been in production use for decades.  ZFS is still wet behind
>>> the ears. Older versions of NetBSD have soft updates, and they work
>>> fine for me. I believe that NetBSD 6.0 is the first release without
>>> soft updates.  They claimed that soft updates was "too difficult" to
>>> maintain.  I find that soft updates are *essential* for data
>>> integrity (I don't know *why*, I'm not a FFS guru).
>>
>> NetBSD didn't simply drop soft-updates, they replaced it with
>> journalling, which is the approach used by practically all modern
>> filesystems.
>>
>> A number of people on the questions list have said that they find
>> UFS+SU to be considerably less robust than the journalled filesystems
>> of other OS's.
>
> What I've seen claimed is that UFS+SUJ is less robust.

This has been my experience.  Soft updates are fine, journaling not so 
much.  After enough initial problems, I stopped using it, so it may be 
better lately.  It still prevents using dump(8), though.