12 May
2017
12 May
'17
12:21 a.m.
Yeah, I get ordered writes, I taught a CS course at Stanford and I made
my students learn all about them. I'm a UFS guy, so far as I know I'm
the last guy to push UFS/FFS forward (which is sort of sad).
The Linux stuff is better. It just is. And we should all respect that,
I know we sit around and love on ancient Unix, and believe me, I love
that stuff it changed the world, but we should respect people who have
moved it past what Unix did. And I think Linux moved the file system
past what Unix did.
--lm
On Thu, May 11, 2017 at 07:48:27PM -0400, Ron Natalie wrote:
Ordered writes go back to the original BSD fast file
system, no? I seem
to recall that when we switched from our V6/V7 disks,
the filesystem got a lot more stable in crashes.
-----Original Message-----
From: TUHS [mailto:tuhs-bounces@minnie.tuhs.org] On Behalf Of Dave Horsfall
Sent: Thursday, May 11, 2017 7:47 PM
To: The Eunuchs Hysterical Society
Subject: Re: [TUHS] The evolution of Unix facilities and architecture
On Thu, 11 May 2017, Larry McVoy wrote:
[...]
--
---
Larry McVoy lm at mcvoy.com http://www.mcvoy.com/lm
Try the same thing with Linux. The file system
will come back,
starting with, I believe, ext2.
That's a journalled FS, isn't it? In which case the transactions get
replayed.
My belief is that Linux orders writes such that
while you may lose
data (as in, a process created a file, the OS said it was OK, but that
file will not be in the file system after a crash), but the rest of
the file system will be consistent. I think it's as if you powered
off the machine a few seconds earlier than you actually did, some
stuff is in flight and until they can write stuff out in the proper
order you may lose data on a hard reset.
And FreeBSD (at least) has been doing ordered writes for quite some time.
--
Dave Horsfall DTM (VK2KFU) "Those who don't understand security will
suffer."