On 18/07/12 18:11, Carl Kabbe wrote:
We are actually facing both capacity and availability issues at the
same time.
Our current primary server is a Dell T410 (single processor, 32 GB
memory) with a Dell T310 (single processor, 16GB memory) as backup.
Normally, the backup server is running as a slave to the primary
server and we manually switch it over when the primary server fails
(which it did last Saturday morning at 2:00AM.) The switch over
process takes 10-15 minutes although I am reducing that to about five
minutes with some scripting (the changeover is a little more complex
than you might think because we have a middle piece, also MySQL, that
we use to determine where the real data is.) Until six months ago,
the time delay was not a problem because the customer processes could
tolerate such a delay. However, we now have a couple of water parks
using our system at their gate, in their gift shops and in their
concessions so we need to now move the changeover time to a short
enough period that they really don't notice. Hence, the need I have
described as 'high availability'.
Hello. May I direct you to these guys: http://www.hastexo.com/ ? They do
High Availability consulting and implementation. They seem to know their
stuff and I'm certain they could help you.
The T410 is normally reasonably capable of processing our
transactions, i.e., the customers are comfortable with the latency.
However, we have been on the T310 since last Saturday and it is
awful, basically barely able to keep up and producing unacceptable
latency. Further, our load will double in the next six months and
double again the the following six months.
So, my thought was that since we have to deal with the issue change
over time which will cause us to restructure the servers, that we
should also deal with the capacity issue. I think a couple of Dell
T620's will provide the capacity we need (the servers we have spec'ed
should be around 8X faster than the T410) but I have no experience
evaluating or setting up HA systems (I have worked with MySQL for 12
years and am reasonably comfortable with it and I have read
everything I can find about HA options and their implementations.)
Hence, my post asking for help (which we are willing to pay for.)
The web app is primarily JSP's for the administration side and Flash
for the operators and other people doing transactions. The server
side code is about 1.25 million lines of code and there are about 750
JSP's. The data is 950 tables with heavy use of foreign key
constraints. The container is Tomcat which runs on separate servers
(the data servers only run MySQL.)
Any ideas or help in any way are always welcome.
Thanks,
Carl
On Jul 18, 2012, at 9:42 AM, Shawn Green wrote:
On 7/17/2012 8:22 PM, Carl Kabbe wrote:
On Monday, I asked if there were consultants out there who could
help set up an NDB high availability system. As I compared our
needs to NDB, it became obvious that NDB was not the answer and
more obvious that simply adding high availability processes to
our existing Innodb system was.
So, I am back asking if there are consultants lurking on this
list that could help with this project.
As has been discussed on this list many times before, there are
many ways to measure 'high availability'. Most of them deal with
what kind of disaster you want to survive or return to service
from. If all you are looking for is additional production capacity
then the terms you may want to investigate are 'scale out',
'partitioning', and 'replication'. All high-availability solutions
require at least some level of hardware redundancy. Sometimes they
require multiple layers in multiple locations.
Several of those features of MySQL also help with meeting some
high-availability goals.
Are you willing to discuss your specific desired availability
thresholds in public?
--
Adrian Fita
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