Replacing apache with nginx
gmm at csdoc.com
Wed Oct 1 01:15:12 MSD 2008
On Tuesday, September 30, 2008 at 22:50:16, mike wrote:
>>>> Sessions need to be sticky - so the user goes
>>>> to the same server all the time, after the session is started.
>> m> i'm always curious why people require sticky sessions.
>> m> with database-backed or some other central storage
>> m> (hell even files over NFS) i don't see the need for this at all.
>> there is one good reason: shared session storage is single point of failure.
if the shared session storage are not redundant - we must
use sticky sessions if want avoid single point of failure
m> And per-server session affinity is no different.
m> Still a single point of failure.
if one of backend servers fail - it will be marked
as failed, but rest backend servers will works fine.
the future clients requests will not be
routed by nginx to failed backend server.
but if dedicated session storage server fail -
all backend servers can`t work with sessions...
this is reason why session affinity is better,
if the session storage server is not redundant.
m> Also if sessions are that important you can
m> easily make central session management redundant.
it is not so easy to do if SQL Server is not redundant
in multi-master mode ( for read and write operations )
PS sorry for my bad english,
it is not my native language.
More information about the nginx