Monitoring server for crashes

Valeri Galtsev galtsev at
Fri Aug 12 16:10:32 UTC 2016

On Fri, August 12, 2016 10:51 am, Robert Fitzpatrick wrote:
> Valeri Galtsev wrote:
>> Before doing such monitoring I would really do a good hardware test.
>> Incidentally, who is hardware manufacturer (just for my curiosity). The
>> usual suspects are: memory (poor/flaky memory, or combination of memory
>> with slightly different specs; these even though they may work together
>> can lead to failure sometimes very rarely, like once every 6 Months
>> which
>> is really hard to troubleshoot: just avoid this). Another possibility:
>> tripping temperature threshold set in BIOS. (These, BTW will leave no
>> tracks in crash, logs etc.) Check this and bring threshold some 15-20 F
>> (7
>> - 10 C ) up. Incidentally: which CPU(s) do you have? (I'm used to think,
>> AMD will withstand any abuse without failing: you almost can boil water
>> on
>> these, Intels are not as robust). What I would do is : open the box,
>> leave
>> minimal hardware (run with minimal amount of RAM, remove all extra cards
>> etc) and see if you have problem with this minimal hardware
>> configuration.
>> If not, start adding hardware, install all RAM first, test if it doesn't
>> crash. Run memtest96 at this point for at least 48 hours (or at the very
>> minimum 2-3 full loops of test). In this configuration try to run system
>> and create significant CPU load (several multi-thread "build world" can
>> help do that), and simultaneously try to use all the RAM. Things are
>> slightly different under heavy load. And so on - add the rest of
>> hardware
>> and test... One more thing: check if your PS provides at least 30% more
>> power than all hardware may need. Marginally insufficient power may lead
>> to unpredictable thing on PCI bus. Incidentally, how old is power supply
>> (and the rest of hardware). Electrolytic capacitors may loose
>> capacitance
>> with age, thus not filtering well enough ripple on PS leads (capacitors
>> inside PS), on CPU power leads and on PCI bus power lines (capacitors on
>> system board - check if they do not showing traces of leakage).
> Thanks for all the suggestions, will check temp and other info in BIOS
> tonight, I really can't have the server down for long memory test, will
> make sure all memory is the same. The server is IBM x3650 with 2 Quad
> Core Xeon L5420 a mixture of drives using hardware ServeRAID 8k and 12GB
> of RAM.

Sound like memory under heavy load. I definitely would:

1. re-seat all RAM modules.

2. While doing 1 check all modules are same brand same part number. I
don't remember off hand if your CPU has its memory controller (like in AMD
opterons) or it is older "memory bus" used by all CPUs, and memory
controller sits on system board, In last case I would just stick extra FAN
on that memory controller chip. If memory controllers are on CPU dies, the
make sure that memory modules connected to given CPU are the same; they
can be [somewhat] different from ones connected to different CPU.
Basically: all RAM modules connected to the same memory controller should
be teh same.

Do I get it correctly: this machine (purchased used) originally run
without problems for you (for multiple Months), right?

One more thing I wouldn't exclude: used system board may have fried
PCI-express slot, if you have something in it, the machine will be flaky.
I had it once ;-( If you can remove everything, or just move extra cards
to different slots, this may help you to test this.

Good luck!

> I purchased second hand in 2011. I have a screenshot of the
> product data screen in the BIOS, it has a diagnostics date of Aug 2009
> in the BIOS, all hardware should be original except drives and memory.
> The load comes from a PostgreSQL database primarily, also provides DNS
> and LDAP services. Not sure heat is the issue, mainly happens at the
> same general time at night, heaviest load is definitely during the day.
> I see now, most of the time it happens during dumping of the db each
> night, but it has happened once during the day and once a couple of
> hours before backup. I'm leaning toward a memory issue and will
> definitely visit the data center tonight and see the types. The db size
> has not changed much over time and this just started recently. It is a
> SpamAssassin/ClamAV db and purges, vacuums every night after dumping. I
> will disable and do dump manually tonight, 90% of the time it seems to
> be going down during backup of the largest db. Perhaps the crashes have
> caused a table to corrupt, I 'fsck -y' all mounts in single user mode
> after every crash.
> --
> Robert
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Valeri Galtsev
Sr System Administrator
Department of Astronomy and Astrophysics
Kavli Institute for Cosmological Physics
University of Chicago
Phone: 773-702-4247

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