Re: [gentoo-desktop] Re: System problems - some progress

[Lindsay Haisley]

On Sat, 2011-03-26 at 08:40 +0000, Duncan wrote:
> By contrast, Linux is still my hobby, tho really, a full time one in that
> I spend hours a day at it, pretty much 7 days a week.  I'm thinking I
> might switch to Linux as a job at some point, perhaps soon, but it's not a
> switch I'll make lightly, and it's not something I'll even consider
> "selling my soul for" to take -- it'll be on my terms or I might as well
> stay with Linux as a hobby -- an arrangement that works and that suits me
> fine.

What professional work I've gotten with Linux has been a real lesson in
synergy.  It seems as if every time I've gone out and experimented with
some facet of Linux technology - setting up iptables, learning routing
fundamentals, setting up and using OpenVPN, etc., I've been called upon
to use it, and get paid for using it, for a client.  My main client, in
return, has increased my understanding of higher level programming stuff
tremendously!  

> Slowly, one at a time, I've tackled Bind DNS, NTPD, md/RAID, direct
> netfilter/iptables (which interestingly enough were *SIGNIFICANTLY* easier
> for me to wrap my mind around than the various so-called "easier" firewall
> tools that ultimately use netfilter/iptables at the back end anyway,
> perhaps because I already understood network basics and all the "simple"
> ones simply obscured the situation for me) and other generally considered
> "enterprise" tools.

Yep, I know where you're coming from there.  Iptables isn't all that
hard to understand, and I've become pretty conversant with it in the
process of using for my own and others' systems.  I'd always rather deal
with the "under the hood" CLI tools than with some GUI tool that does
little more than obfuscate the real issue.  That way lies Windows!

> Bottom line, yeah I believe ext4 is safe, but ext3 or ext4, unless you
> really do /not/ care about your data integrity or are going to the extreme
> and already have data=journal, DEFINITELY specify data=ordered, both in
> your mount options, and by setting the defaults via tune2fs.

So does this turn off journaling?  What's a good reference on the
advantages of ext4 over ext3, or can you just summarize them for me?

> But if you're basing the initr* on glibc, which would certainly be easier
> and is, now that I think of it, probably the way gentoo handles it, yeah,
> I could see the glibc getting stale in the initrd.

The problem with Gentoo was that because EVMS was an orphaned project, I
believe the ebuild wasn't updated.  The initrd file was specific for
EVMS.

> If there's one bit of advice in all these posts that I'd have you take
> away, it's that.  It's NOT worth the integrity of your data!  Use
> data=ordered unless you really do NOT care, to the same degree that you
> don't put data you care about on RAID-0, without at least ensuring that
> it's backed up elsewhere.

I've never used, or had much use for RAID-0.  LVM provides the same
capabilities.  For me, RAID is a way of insuring data integrity, and
large drives are getting cheaper and cheaper.  I've only used RAID-1 and
RAID-5.

I'm not a speed-freak on disk I/O, and am generally quite willing to
sacrifice a bit of speed for reliability.  data=writeback has been a
tweak, and I believe I've read up on it previously and decided against
it for probably the same reasons you cite.  data=ordered has been the
default, but apparently upgrading to 2.6.36 I'm going to have to spec
this explicitly in /etc/fstab unless I upgrade to 2.6.38.

> FWIW, my RAID is 4x SATA 300 gig Seagates, 5 year warranty I expect now
> either expired or soon to.  Most of the system is RAID-1 across all four,
> however, and I'm backed up to external as well altho I'll admit that
> backup's a dated, now.  I bought them after having a string of bad luck
> with ~1 year failures on both Maxtor (which had previously been quite
> dependable for me)

I had a Maxtor drive actually *smoke* on me once, years ago.  There was
a "pop", and smoke, and a big burned spot on the circuit board on the
drive!  I never bought another Maxtor!  It's the smoke inside the little
colored thingies on printed circuit boards that make them work!  When
they break, and the smoke gets away, the thingies are useless.

I generally go with Seagates these days too, although the quality of
drives, and which brand is best, seems to change over time.  I used to
swear by IBM drives until they had a bad run of them with a high failure
rate, and before this got sorted out they sold their drive biz to
Fujitsu.  

>  and Western Digital (which I had read bad things about
> but thought I'd try after Maxtor, only to have the same ~1 year issues).
> Obviously, they've long outlasted those, so I've been satisfied.
>
> As I said, I'll keep the 3ware RAID cards in mind.

After having had all kinds of trouble trying to get hardware RAID
working on one of my servers, I discovered the 3ware cards after asking
the advice of the hardware fellow here who works with one of my favorite
tech outfits in Austin, Outernet Connection Strategies.  He builds a lot
of servers and doesn't even _try_ to get the native RAID chipsets to
work.  He just slaps a 3ware card in them and moves on.  It's _real_
RAID, all the useful levels, not "fakeraid".  

> Mainboard:  If a server board fits your budget, I'd highly recommend
> getting a Tyan board that's Linux certified.  The one I'm running in my
> main machine is now 8 years old, /long/ out of warranty and beyond further
> BIOS updates, but still running solid.

Hmmm.  I'll look into Tyan.  I hadn't heard of them, but it sounds as if
they bend over backwards to work with Linux.  That's always a plus.

> It's likely to be a decade old by the time I actually upgrade it.  Yes,
> it's definitely a server-class board and the $400 I paid reflected that,
> but 8 years and shooting for 10!  And with the official Linux support
> including a custom sensors.conf.  I'm satisfied that I got my money's
> worth.
>
> But I don't believe all Tyan's boards are as completely Linux supported as
> that one was, so do your research.

Of course.  I like technology that _lasts_!  We have a clock in our
house that's about 190 years old, and came to me through my family.  The
works are made of wood, and it keeps impeccable time - loses or gains
maybe 30 seconds a week if I wind it every day, which I need to.  Some
years ago one of the wooden gears gave out from over a century of
stress.  There's a label in the clock that says "warrented if well
used", and since I'd used it very well, I called up the Seth Thomas
company and told them that I had one of their clocks and it was broken,
and since I'd used it very well, I figured that it was still under
warranty.  The gal with whom I talked was amused and intrigued, and
turned me on to the Connecticut Clock and Watch museum, run by one
George Bruno.  It seems that Mr. Bruno also makes working replicas of
exactly the model of clock I have and was able to send me an exact
replacement part!  Try _THAT_ with your 1990's era computer ;-)  Every
time this nice old clock strikes the hour it reminds me that although I
work with computers where hardware is out of date in 5 years or so,
there are some things that were built to last!

But this is OT for this forum.  Sorry, folks.  I couldn't resist telling
a good story.

> Well, save btrfs for a project a couple years down the line, then.  But
> certainly, investigate md/raid vs lvm2 and make your choice, keeping in
> mind that while nowdays they overlap features, md/raid doesn't require an
> initr* to run / on it, while lvm2 will likely be pulled in as a dependency
> for your X desktop, at least kde/gnome/xfce, by later this year, whether
> you actually use its lvm features or not.

Thanks, Duncan.  Good advice, that.

> And do consider ext4, but regardless of ext3/4, be /sure/ you either
> choose data=ordered or can give a good reason why you didn't.  (Low-
> latency writing just might be a reasonable excuse for data=writeback, but
> be sure you keep backed up if you do!)  Because /that/ one may well save
> your data, someday!

I'm going to read up on btrfs and ext4, whether or not I use them.

-- 
Lindsay Haisley       |"Windows .....
FMP Computer Services |    life's too short!"
512-259-1190          |
http://www.fmp.com    |              - Brad Johnston