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Re: failed tests

From: Prateek Srivastava <for.groups_at_gmail.com>
Date: 2005-06-06 07:06:56 CEST

Hi Konrad/Erik,

Thank you for the valuable suggestions.
I will check it out. But my monitor broke down yesterday. I will check
that when it is fixed.

Maybe the components are bad. But, still I find Erik's coments more
logical and explainable.

Thanks guys!


On 6/4/05, Konrad Rosenbaum <konrad@silmor.de> wrote:
> On Saturday 04 June 2005 13:12, Prateek Srivastava wrote:
> > My machine is new and well configured.
> > > Is your HD or memory starting to show its age?
> I saw problems like this many times on new machines with load-intensive
> software. It is common practice to produce machines with very cheap
> components - why bother with ECC-RAM, good high-datarate cables, and
> server-grade Harddisks if 95% of these machines will run Windows anyway and
> users are used to blame it on the OS or their own inability?
> Tips for diagnosis:
> *let a memory tester run over night - if it does find something then you've
> got VERY bad memory chips, if it doesn't you unfortunately won't know for
> sure (if you run SuSE: it is on the install DVD, just boot into memtest
> instead of into Linux)
> *check that all disk cables are properly connected and don't have sharp
> bends or even lose connectors
> *have you switched on ATA-133 or other high-speed modes? (Linux: hdparm)
> Switch them off and try again.
> *Often you get indications of problems if you do dmesg (Linux-specific
> though) - if you get lines like "hdb: lost interrupt" it means the
> communication between your mainboard and the disk is bad.
> *does the same problem occur on a different system? (if you have a real
> server - not just a PC posing as one - use the server for this test) If
> yes: it is either a problem with the OS (faulty library) or coincidence
> (test on a third system) or really a problem with SVN. If no: you've got a
> problem with the hardware.
> Tips for the next system:
> *never buy pre-configured systems from big end-consumer retailers - these
> are Cheap[tm], I personally use very small computer shops, preferably those
> that regularly deliver small servers to business customers and do the
> support for those - these guys have the most experience with how to build a
> good system that is still in your budget
> *use workstation or server boards - ok they are expensive, but they have the
> plus of requiring and supporting ECC-RAM:
> *use ECC-RAM - DRAM cells are extremely susceptible to bit flips (the
> probability of a flip goes up exponentially with temperature and with the
> amount of bits in the system), ECC-RAM is twice as expensive because it a)
> uses good chips (which passed ALL tests instead of only the barely
> necessary ones) and b) is able to fix almost all bit-flip situations (I've
> NEVER had problems with ECC, but constantly have them on normal cheap
> chips)
> *while we are on it: use server processors - they are also twice as
> expensive because they had to endure twice as many tests and have a twice
> as large margin (a processor that would be sold as a 2.5GHz consumer
> machine would be sold as a 2.0GHz server machine)
> *use cables that actually support high-data-rates and use server-grade
> harddisks (the lower ranges of server-disks are not much more expensive
> than consumer disks), don't use spin-down or disk suspend, since
> server-disks are not optimised for that mode
> *let your supplier/retailer built in powerful fans - there are fans that are
> both powerful and silent today (I'll never do that myself again after I
> ruined two mainboards with underpowered CPU-fans).
> Ok, this all sounds terribly paranoid and expensive. Actually: it is. Both
> of it. It comes from a lot of bad experience with "consumer grade" systems
> and some great experiences with "server grade" workstations. You pay a lot
> for that, but at least I can be sure that if something goes wrong now it is
> the software.
> Even if you don't want to go to these extremes: use one of those small shops
> that do daily support for small business people and talk to them. They know
> which kind of consumer-systems are often returned for repair and which
> aren't... ;-)
> Konrad

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Received on Mon Jun 6 07:08:48 2005

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