
The 3.9 kernel is out - edwintorok
http://lwn.net/Articles/548786/rss
======
freeman478
Particularly interesting is the possibility of using a SSD as a cache for a
HDD just like the Fusion Drive in the recent iMacs
([https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux....](https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/plain/Documentation/device-
mapper/cache.txt?id=c6b4fcbad044e6fffcc75bba160e720eb8d67d17))

Reviews were quite positive of Apple implementation. Has anybody tried the
linux version ?

~~~
dsr_
I've got flashcache running on a 20GB SSD partition fronting a 120GB spinning
disk partition, on a desktop at home. It feels (anecdotal, subjective) as fast
as a pure SSD for all normal desktop things. I also ran a small MySQL db
through this setup for a few weeks, and that improved noticeably over a single
spinning disk, especially when there was IO load from other processes.

The install procedure is a little rough around the edges, so I'm looking
forward to having that more polished.

------
girvo
I'm quite interested in the user namespaces feature, but can't come up with
any use cases for myself other than say sandboxing (sort of) applications. Can
anyone explain it a bit better? The lwn article is a bit heavy going

~~~
FooBarWidget
It was primarily designed for sandboxing, so it's not strange that you cannot
come up with other use cases.

~~~
girvo
That... Would make sense then. Now I feel stupid ;)

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wladimir
It looks like the kernelnewbies.org page is getting stampeded and is
unreachable. Too bad, they usually have a nice high-level overview of the new
kernel features and changes.

~~~
edwintorok
The H also has an overview, but I usually prefer KernelNewbies too:
[http://www.h-online.com/open/features/What-s-new-in-
Linux-3-...](http://www.h-online.com/open/features/What-s-new-in-
Linux-3-9-1845705.html)

------
srisa
Am I the only one who feels that the kernel releases have been more frequent
during recent times? Or is it that they have changed the version numbering
like firefox?

About an year or so ago, it was something like 2.6.x. Then, it jumped to 3.0
and now it is at 3.9.

~~~
andrewaylett
Linux jumped from 2.6.39 to 3.0 because the numbers were getting too big. He
also decided that as the middle digit wasn't being incremented, he'd drop it.

~~~
srisa
I remember seeing 2.6.42 on my ubuntu 10.04. May be it was kind of an alias
for some 3.x version.

~~~
jeltz
Yeah, some software assumed that there must be three digits in version numbers
so 3.X kernels were sometimes called 2.6.X+40 which means 2.6.42 actually is
3.2.

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demetris
From the first paragraph of the announcement:[1]

“makes me suspect [...] people were gaming the system and had timed some of
their pull requests for just before the release”.

Does anyone know what Linus means by that?

[1] <http://lwn.net/Articles/548799/>

~~~
edwintorok
Pull requests this late in the -rc cycle should contain only important
bugfixes, other changes should normally wait for the next kernel release. For
example Linus ignored some pull requests sent for 3.6-rc2 that didn't really
belong there: <https://lkml.org/lkml/2012/8/16/577>

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ippa
Been waiting for raid5 with btrfs!

~~~
kostya-kow
How stable is btrfs at this point?

~~~
ElliotH
I use it full time on my Desktop and my Laptop. It glitches fairly often but
nothing unrecoverable. You'll mostly run into issues if you run out of space.
Also there's some weird side effects with improper shut-down that you should
note. Btrfs tends to leave some stuff in my logs too, but nothing that
actually lost data, normally I see the error after a brief lockup in the
system.

~~~
iso8859-1
> glitches

Panic? OOPS?

~~~
ElliotH
Mainly oops left in my logs, one or two panics on shutdown. Once a panic when
I was doing something silly with my uni research project.

Pity I can't report these really, tainted (AMD) kernel.

