What sort of MTTR latency is acceptable for these memcache calls that you will be making from / to these cloud based servers?
Jeremy On Tue, Feb 10, 2009 at 9:53 PM, Travis Bell <[email protected]> wrote: > 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]> 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] > >
