PFC writes:
You say that like you don't mind having PCI in a server whose job is to
perform massive query over large data sets.
I am in my 4th week at a new job. Trying to figure what I am working with.
From what I see I will likely get as much improvement from new hardware as
from re-doing some of the database design. Can't get everything done at
once, not to mention I have to redo one machine sooner rather than later so
I need to prioritize.
In fact for bulk IO a box with 2 SATA drives would be just as fast as
your monster RAID, lol.
I am working on setting up a standard test based on the type of operations
that the company does. This will give me a beter idea. Specially I will work
with the developers to make sure the queries I create for the benchmark are
representative of the workload.
Adding more drives will help random reads/writes but do nothing for
throughput since the tiny PCI pipe is choking.
Understood, but right now I have to use the hardware they already have. Just
trying to make the most of it. I believe another server is due in some
months so then I can better plan.
In your opinion if we get a new machine with PCI-e, at how many spindles
will the SCSI random access superiority start to be less notable? Specially
given the low number of connections we usually have running against these
machines.
If you mean doing large COPY or inserting/updating lots of rows using one
SQL statement, you are going to need disk bandwidth.
We are using one single SQL statement.
http://tweakers.net/reviews/557/17/comparison-of-nine-serial-ata-raid-5-adapters-pagina-17.html
I have heard great stories about Areca controllers. That is definitely one
in my list to research and consider.
However RAID5 will choke and burn on small random writes, which will come
from UPDATing random rows in a large table, updating indexes, etc. Since
you are doing this apparently, RAID5 is therefore NOT advised !
I thought I read a while back in this list that as the number of drives
increased that RAID 5 was less bad. Say an external enclosure with 20+
drives.
Have you considered Bizgres ?
Yes. In my todo list, to check it further. I have also considered Greenplums
may DB offering that has clustering, but when I initially mentioned it there
was some reluctance because of cost. Also will look into Enterprise DB.
Right now I am trying to learn usage patterns, what DBs need to be
re-designed and what hardware I have to work with. Not to mention learning
what all these tables are. Also need to make time to research/get a good
ER-diagram tool and document all these DBs. :(
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