Re: Which version will be merged into mainline kernel?

[Christopher Chan <chrisfz@netvigator.com>]

>> Which is why data important software use fsync/fsyncdata to minimize 
>> data loss from crashes.
> 
> If (and only if) you actually read and accepted the paragraph you're 
> quoting there, the point is that using fsync and fdatasync on these is 
> kind of like doing bad block relocation in software, when the hard disk 
> is already doing it for you. There are situations where it's useful, but 
> mostly, it's just a performance drain without a point.

You have no idea what fsync/fsyncdata does. They cannot be compared to 
bad block relocation at all. That is an apples to oranges comparison.

> 
> I don't necessarily agree with this point of view, but there you go.
> 
>>> could probably argue the other side just as effectively. Besides, at
>>> least on my experimental/gaming rig, I like a little adrenaline in my
>>> admin work!
>>>
>>
>> Try arguing why you lost thousands of mails when the box crashed and 
>> justifying it.
> 
> There aren't thousands of mails on my experimental dev/gaming rig. Also, 
> it hasn't crashed in a month or two (I seem to have upgraded/hacked my 
> way out of its last major crasher), and it's running all kinds of 
> experimental stuff. Sure, individual programs crash from time to time 
> (especially my hacks), but that's irrelevant to the fsync discussion.

I was not referring to your gaming rig. Did you say that you don't use 
fsync for your production boxes?

> So, as far as I can tell, this mailserver (that I'm sending this from 
> right now), which is amd64/reiser4/no_fsync, hasn't lost a single 
> message. And I don't even have an APM on it (although that reminds me, I 
> need to buy one now, as in, "tomorrow" now.)

Heh. Just wait till you get a crash shortly after a write with fsync 
disabled.

> 
> Anyway, are we done here? I don't think I disagree with your points, 
> maybe just your absolutism.

Ha! Got tell that to a bank or any body who uses a database to store 
important data. Hans knows what he is doing providing data guarantee 
with fsync. I was very surprised when I heard all those reports about 
zero data loss on reiser4 boxes after a crash. Now I have an idea why.