> There are two parts here: > Thanks Shamit for your detailed explanation.
> > 1. Fail over of persistent data (DB, SAN Volume with Video Content etc) > 2. Load balancing on stateless web hosts > > Issue#2 is very easy to solve, issue#1 is difficult (unless big-budget that > makes SAN mirroring feasible across two data centers). > > One way to solve these issues is to use AWS / Azure etc. With these: > We may not be having Internet connectivity to do so.Everything happening in Intranet. > > 1. You can use DB and Storage offering provided by Amazon/Google/Azure > 1.a : These offering include HA for DB + Storage > 1.b: DB is completely managed by provider (scaling / updates / high > availability) > 1.c: Storage is mounted as a block device and can be formatted as > any filesystem (ext3/ext4) > 2. For web tier, you can use any Linux AMI and either > 2.a: Use load balancer OR > 2.b: Setup monitoring to spin up a new VM if primary crashes (or load > goes beyond a threshold in web tier VM(s)) > > > With this setup, initial cost in close to Zero and user will not even > notice if any component fails over. Say, user is playing a video and > Storage fails over. in This scenario: > > 1. Http server serving video content anyways has to support streaming ( > Http 206 for Partial Content, Range, ETag) > > 2. Player on client side will always ask for video content in small chunks > 3. As any tier fails over, next chunk will be served by failed over tier > 4. User's data (DB records for authentication/ preferences) will > transparently be failed over by provider. > > Hope that helps, > Yes..Will definitely explore this further. > Shamit > > -- Siji Sunny -- http://mm.ilug-bom.org.in/mailman/listinfo/linuxers
