[CentOS] Good value for /proc/sys/vm/min_free_kbytes
MrKiwi
mrkiwi at gmail.com
Fri Dec 8 01:02:02 UTC 2006
John R Pierce wrote:
> Morten Torstensen wrote:
>> John R Pierce wrote:
>>> certainly are. The database adminstrators will spend hours pouring
>>> over IO logs and database statistics in order to better optimize the
>>> distribution of tables and indicies across the available tablespaces.
>>
>> Didn't realise Oracle was that primitive. One should just balance all
>> the tablespaces out over multiple volumes and or controllers and add
>> table partitioning as needed. Transaction filesystem is a striped
>> filesystem over the same raid/volumes.
>>
>> Then if you need more I/O bandwidth you just add more controllers and
>> disks.
>
> thats the shotgun approach, yes.
> in our case, our production systems are a very large very complex
> realtime oracle database running on large scale Sun enterprise hardware
> on bigiron EMC storage, using dozens and dozens of raid10 logical
> volumes as you do NOT want to have a single 10TB volume, sorry. by
> hand optimizing the tablespace layouts of the applications tables and
> indicies, which have very specific access patterns, we can get double
> the throughput of the blind 'just stripe the universe' approach. Since
> we're dealing with $millions worth of servers here at each production
> factory, tossing more iron at the problem isn't always the best
> solution. btw, we've found Oracle 10's new 'self optimizer' to do a
> far worse job of query optimization than what we have been able to hand
> tune out of Oracle 9, so we're not upgrading until this changes.
>
> we're embarking on a pilot project to evaluate a smaller scale version
> of this manufacturing execution system on linux + postgres as there are
> smaller installations which can't justify the costs of Oracle.
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Just out of curiosity John, are you allowed to give us some
hints about what your system does? If you are posting on the
CentOS list i presume you are running CentOS, rather than "a
similar upstream product".
Also I'd love to know what you mean by "you do NOT want to
have a single 10TB volume" - are you referring to
performance or single-point-of-failure issues?
Regards,
MrKiwi
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