Load Balancing in a Multiple Server System Hosting an Array of Services
A method and system for load balancing in a multiple server system supporting multiple services are provided to determine the best server or servers supporting a service with the best response time. An induced aggregate load is determined for each of the multiple services in accordance with corresponding load metrics. A maximum induced aggregate load on a corresponding server that generates a substantially similar QoS for each of the plurality of services is determined. A load balancing server distributes the multiple services across the multiple servers in response to the determined induced aggregate and maximum induced aggregate loads, such that the QoS for each of the multiple services is substantially uniform across the servers.
1 . A computer readable medium for storing instructions which, when executed by a processor, perform a method for load balancing in a multiple server system supporting multiple services, the method comprising:
determining an induced aggregate load for each of said multiple services in accordance with corresponding load metrics;
determining a maximum induced aggregate load on a corresponding server adapted to generate a substantially similar Quality of Service (QoS) for each of said multiple services; and
distributing said multiple services across said multiple servers in response to said determined induced aggregate and maximum induced aggregate loads, wherein the determined QoS is substantially achieved across said servers.
2 . The method of claim 1 , wherein the load metrics further comprise one or more of a number of active connections, central processing unit (CPU) load, memory consumption, available memory, input/output (I/O) bandwidth consumption and network throughput.
3 . The method of claim 1 , wherein QoS further comprises one or more uniform response time, bit rate, delay and jitter.
4 . The method of claim 1 , wherein a single server performs multiple services.
5 . The method of claim 1 , wherein different servers host a different mix of services.
6 . The method of claim 1 , wherein the aggregate load for each of said multiple services is expressed by:
L
(
j
)
=
∑
i
=
1
n
l
(
i
,
j
)
where l=load metric; and j=a specific server.
7 . The method of claim 1 , wherein the maximum aggregate load on the corresponding server is expressed by:
M ( r ( i, j ))=max { L ( j )| f ( L ( j ))= r ( i, j ))}
8 . The method of claim 1 , wherein the load balancing system determines for each incoming packet request, which of said one or more servers are running the corresponding service.
9 . The method of claim 1 , wherein among all the servers running the service the load balancing system forwards the request to a single server satisfying the load condition.
10 . The method of claim 1 , wherein when there are multiple servers satisfying the load condition, the load balancing system forwards the request to a server selected on the following policies: random, least-server-id, last-server-selected and round robin.
11 . The method of claim 10 , wherein when the loading is insignificant the load balancing system forwards the request to a server selected on the following: random, least-server-id, last-server-selected and round robin.
12 . A multiple server system supporting multiple services, comprising:
at least one load balancing server communicatively coupled to at least one server supporting multiple services, each load balancing server adapted to distribute said multiple services wherein a QoS for each of said multiple services is substantially uniform across one or more servers supporting a corresponding service; and
one or more networked servers adapted to compute a respective induced aggregate load and a maximum induced aggregate load for each of multiple services supported by said servers.
13 . The load balancing system of claim 12 , wherein upon failure of a server, the load balancing system moves said server's state and operations to a backup server.
14 . The load balancing system of claim 12 , further comprising a Flow Balancing table adapted to redirect a flow to a server.
15 . The load balancing system of claim 12 , further comprising a Server Mapping table.
16 . The load balancing system of claim 13 , wherein upon switch-over to the backup server the physical server id of the failed server is updated to that of the backup server in the Server Mapping table.
17 . The load balancing system of claim 16 , wherein the best QoS further comprises the least a response time.
18 . A computer readable medium for storing instructions which, when executed by a processor perform a method for load balancing in a multiple server system supporting multiple services, the method comprising:
determining the QoS for each of said multiple services running on a corresponding server; and
transmitting, a new request for service to the server with the best QoS for a corresponding service.
19 . The method of claim 17 , wherein the load balancing system forwards the request to a server selected on predefined policies.