Hey Marc,
Thanks, this is a good idea the right way to do it. Appreciate the comment.
--
Travis
Marc Bollinger wrote:
Agreed. From experience, in all likelihood, this is _not_ what you
want to do (it sounds like you're talking about maintaining a
memcached server on each app server). If you're even thinking about
scaling by CPU, you should be able to afford at least one m1-small
server lying around with memcached using all of the memory you can
throw at it, and bring up app servers separate, as needed. If for one
reason or another you absolutely, positively need to have memcached
running locally, you're almost certainly better off having a tiered
caching strategy utilizing a caching system native to whatever
framework you're using; there was a discussion here about that a week
or so ago.
On Tue, Feb 10, 2009 at 6:37 PM, a. <[email protected] <mailto:[email protected]>>
wrote:
can't you just have a memcached node and an appserver node?
appservers started later could use the same memcached instance.
On Feb 11, 2009, at 3:35 AM, Travis Bell wrote:
Hey Dustin,
Keep in mind I wouldn't keep these instances running... they
would be
brought up and down as the load needed them to be so maybe I am
missing a key step (which trust me, I most certainly could be)
but I
am not sure how the new instance would even get used based on
what you
said.
Example 1: load gets high so a new EC2 instance is triggered. Once
it's up, I reload the config on my load balancer so requests
are split
across 2 instances, instead of 1. The original instance is
going to
have hundreds of thousands of items cached when the second (new)
instance does not. Whenever a requests gets forwarded to this new
instance it will result in a cache miss and have to go fetch
the item
again.
It seems to me having to re-fetch the item is a bit of a waste
since
it's already cached on the first server... this is what I am
trying to
solve.
Regarding saturating memcached, it's less about that and more
about
all the other things this server is doing behind the scenes so
moving
memcache to a new instance can spare the first box when it is
needed.
Thanks in advance for any more info you guys can provide!
--
Marc Bollinger
[email protected] <mailto:[email protected]>
