cvs commit: src/sys/kern kern_shutdown.c

[Nate Lawson]

Scott Long wrote:
> Nate Lawson wrote:
>> Peter Jeremy wrote:
>>> You still wind up with unwritten data in RAM, just less of it.
>>>
>>> How much effort would be required to add journalling to UFS or UFS2?
>>> How big a gain does journalling give you over soft-updates?
>>
>>
>> Kirk pointed out something to me the other day which many people don't 
>> think about.  None of the journaling systems has had its recovery mode 
>> fully tested, especially on very large systems (dozen TB).  It turns 
>> out that memory pressure from per-allocation unit state is a big 
>> problem when you are trying to recover a huge volume.
>>
>> Just because it says "journaling" doesn't make it good.
> 
> You are very correct that there are issues like this, and that's why I 
> said that it would take a while to chase out the bugs and make it 
> production quality.  However, given the enterprise nature of Sun, I'd
> say it's a bit of a stretch to think that they haven't tested their
> f/s on multi-terabyte arrays.

I was referring to the herd of Linux journaling systems.

> Even Apple advertises multi-terabyte
> storage with their XServe, so I'd be surprised if they hadn't done at
> least some testing there.

 > 2 TB?

-- 
-Nate