[Hidden-tech] Seeking advice on protecting a Linux box from failures

[Robert Heller]

At Thu, 25 Aug 2011 14:05:32 -0400 Daniel Belmont <dbelmont2 at gmail.com> wrote:

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> I have a special purpose Linux machine that is used to run musical
> instruments and is
> used frequently in concert settings ... so preventing failure is of
> importance ... I am
> looking for advice on two things :
> 
> 1) I need a UPS that produces pure sine waves, has reliable battery backup
> that will
> instantly kick in during voltage dips, isn't too heavy (or wildly
> expensive), rack
> mountable would be nice (but I can deal with something that is around 25
> pounds
> even if it is not rack mountable), and does voltage regulation ... someone
> suggested
> that there are UPS's that always provide power from the constantly
> recharging
> battery -- that could be interesting ...
> 
> The reason I am asking for something with these specific qualities is that I
> had a
> power outage at a concert this past weekend -- the LInux box was plugged
> into a
> UPS that puts out simulated sine waves (and the power supply on the Linux
> machine
> does active power factor correction which needs pure sine waves), there was
> a voltage
> dip, the UPS battery kicked in and the Linux box shut down as if it lost
> power due to the
> sine wave mismatch ... apparently this kind of thing can destroy the hard
> drive (which
> would be a big problem) as well as causing problems for Linux startup (this
> did happen
> but that problem seemed to correct itself within a few minutes) ...
> 
> 2) what kind of care do I need to provide to the Linux box so that it works
> like
> a mission critical computer ? the right kind of UPS seems important, backing
> 
> up the hard drive is a given (I am doing this now) ... are there other
> things I need
> to do to treat this computer well ? again, since it is a musical instrument
> I am
> very desirous of eliminating all of the possible causes of failure (to the
> extent that
> I can) ...

Does the machine have a RAID array set up?  Linux's kernel includes a
quite good software RAID implementation.  All you need are two same size
disk drives...  A RAID1 (mirroring) array will let you keep going if one
drive fails. And if you have a spare on hand, you can swap it in during
a break and it can rebuild the array as the concert continues...

Some server systems have hot-swap power supplies, but that might be
overkill... 

Reasonably good shock mounting in your carry case and/or hard drives is
another thing to look at.

It is possible to get something called a ruggedized 'lunchbox' system. 
This is something between a laptop and a desktop.  It would have a
desktop motherboard with the usual PCI bus, etc. and mounting for usual
desktop drives (multiple hard drives, *-ROM drive, etc.), but would
have a smaller keyboard and a stowable *small* flat-panel display the
whole thing packs up to about lunchbox sized with a ruggedized case,
that might include shock mounting for the hard drives.  These machines
are meant for use in tough / harsh environments and meant to withstand
a certain amount of abuse ('tossed' into a plane or boat cargo hold,
bounced in the back of a truck bouncing down a rough dirt road, etc.).
I guess you already have a machine, but someday you might want/need to
replace or upgrade it...

> 
> Thanks !
> 
> Dan Belmont
> The Soul Sensations
> www.TheSoulSensations.com
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-- 
Robert Heller             -- 978-544-6933 / heller at deepsoft.com
Deepwoods Software        -- http://www.deepsoft.com/
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