[Dirvish] backups and system load

Jason Boxman jasonb at edseek.com
Sun Sep 13 17:40:43 UTC 2009


On Thursday 10 September 2009 05:10:29 pm Keith Lofstrom wrote:
> On Thu, Sep 10, 2009 at 04:06:28PM -0400, Jason Boxman wrote:
> > Lately I've lost two PSUs.  Both went down while backups were running.
> > Anyone else experience that?  Nothing like some system load to take a
> > box out.
>
> Interesting!  Tell us more about your setup.   Also, purchase a
> "Kill-A-Watt" power line monitor (about $20 from newegg) and watch
> what the mains power is doing during idle and during backup.

I have one somewhere.  I need to go through all my stuff still a year after a 
move to find everything.  (I have a bunch of dead stuff I still need to toss, 
too, plus one more PSU now.)

> If the backup machine is on a UPS, you should check that, too.

It just moved to a new office.  Was still on wall power at the time.

Actually, during the move the UPS it was on coughed up smoke and took down a 
room breaker.  All the equipment seemed to work fine after, but maybe there was 
a casualty after all.

>
> Observations:
>
> 1)  Rsync/dirvish does thrash the disks a lot.  Unless you do a lot
>     of high power computing, games, or graphics, that is probably
>     the highest activity most servers will see, and when a marginal
>     machine will go.

Yes, it's all a nightly spike on my Munin graphs.

> 2)  Most power supplies, out of the box, are way more powerful than
>     typical systems need.  Even with the disks in full thrash mode.

This was an older 300W (I think) nameless PSU.  I still have to examine the 
carcass.

> 3)  Most systems do not get cleaned often enough.  The accumulated
>     dust interferes with cooling.  Some components overheat.

This case had some rather poor airflow conditions.  Everything had a thick 
layer of dust, including the PSU in take vent.

> 4)  Most PSU manufacturers use garbage components, which don't last
>     very long.  Electrolytic capacitors dry up, too-small resistors
>     cook the circuit board, etc.  I've been using Enlight and Antec
>     supplies, and I stay away from "Happy Family Mixed Vegetable"
>     brands with no reputation.

Yeah, this was one of those.  Later, I started buying CoolMax PSUs, but both I 
had died, one six weeks ago; one took with it a video card.  Now I'm buying 
Silverstone 80Plus 500W PSUs.  No issues yet.

Had a rash of PSU failures lately.  Also just lost the 350W AOpen (rebranded 
FSP) PSU with the ancient 4-pin aux connector.  You can't find it anymore on 
PSUs >300W.  I had to find someone that bought the same case I did that came 
with the same PSU to replace it.  Last time I get a motherboard with odd power 
requirements.  (Old SuperMicro 370DLE mainboard; dual P3 coppermine system.)

Hit end of life on five PSUs this year, actually.  Only two were hit by nightly 
backups, though.

Fortunately, the data in question survived the PSU failure along with the 
3Ware 7500-8 PATA RAID card.

The incident has brought back to the fore the necessity of an additional 
auxiliary backup system, for key files anyway.  DVD-RAM always sounds sexy.  
Our ADSL is too slow to usefully push data elsewhere.

-- 

"Don't put it in your mouth." - Arctic Silver 5 Manual




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