Thanks LesMikesell,for the great explanation , i am helpless here , i am working on a existing application , which is designed in such a way that all the Data is written to Memcache (and there is no Database at all ) which is the only data store currently , so what i was asking is that, will clustering of Memcache Servers will avoid single point of failure ??
Thanks in advance . On Friday, 12 October 2012 22:44:14 UTC+5:30, LesMikesell wrote: > > On Fri, Oct 12, 2012 at 11:31 AM, Kiran Kumar <krn...@gmail.com<javascript:>> > wrote: > > > > Thanks LesMikesell you were right there is nothing mentioned anything > > about data being backed up in that link . > > What i really want to convery is that if one of the Memcahe Server one > is > > is down , then automatically Data is being obtained from Memcahe Server > two > > , which avoids single point of failure . so i don't care if Data is > being > > obtained from any of the defined servers . > > > > ( that is what i mean to say data being copied to other location , i > > sincerely if it creates a different meaning in this context ) > > > > (becuase as a end user i don't bother from which the data is being > > obtained ) > > Memcache should only be used for fast repeated access to _copies_ of > data that can be reliably retrieved from some other database or > storage. There are any number of reasons why a server will not have > the data a client requests (it expired, it was evicted due to lack of > space, the server was restarted, etc.). The client's response to a > cache miss should always be to get the data from the reliable database > and update it into the cache. So it won't matter if any particular > data is lost for any particular reason as long as the backend database > can keep up with the clients requesting the missed data (which they > will then refresh into a rebalanced hash location). If you are > planning to use memcache to store the only copy of data that you can't > reconstruct, you should be looking for some other product. Memcache > is just a very fast distributed cache, not a reliable database. But > as long as you can retrieve the data for cache misses from some other > source you can just add more servers to a cluster to scale to any > size, and other than having to configure each client to know about all > the servers it will take care of itself. > > -- > Les Mikesell > lesmi...@gmail.com <javascript:> >
