Not a member of Pastebin yet?
Sign Up,
it unlocks many cool features!
- /* The mh algorithm is to assign a preference list of all the lookup
- * table positions to each destination and populate the table with
- * the most-preferred position of destinations. Then it is to select
- * destination with the hash key of source IP address through looking
- * up a the lookup table.
- *
- * The algorithm is detailed in:
- * [3.4 Consistent Hashing]
- https://www.usenix.org/system/files/conference/nsdi16/nsdi16-paper-eisenbud.pdf
- *
- */
- scheduling-method Algorithm for allocating TCP connections and
- UDP datagrams to real servers. Scheduling algorithms are imple-
- mented as kernel modules. Ten are shipped with the Linux Virtual
- Server:
- rr - Robin Robin: distributes jobs equally amongst the available
- real servers.
- wrr - Weighted Round Robin: assigns jobs to real servers propor-
- tionally to there real servers’ weight. Servers with higher
- weights receive new jobs first and get more jobs than servers
- with lower weights. Servers with equal weights get an equal dis-
- tribution of new jobs.
- lc - Least-Connection: assigns more jobs to real servers with
- fewer active jobs.
- wlc - Weighted Least-Connection: assigns more jobs to servers
- with fewer jobs and relative to the real servers’ weight
- (Ci/Wi). This is the default.
- lblc - Locality-Based Least-Connection: assigns jobs destined
- for the same IP address to the same server if the server is not
- overloaded and available; otherwise assign jobs to servers with
- fewer jobs, and keep it for future assignment.
- lblcr - Locality-Based Least-Connection with Replication:
- assigns jobs destined for the same IP address to the least-con-
- nection node in the server set for the IP address. If all the
- node in the server set are over loaded, it picks up a node with
- fewer jobs in the cluster and adds it in the sever set for the
- target. If the server set has not been modified for the speci-
- fied time, the most loaded node is removed from the server set,
- in order to avoid high degree of replication.
- dh - Destination Hashing: assigns jobs to servers through look-
- ing up a statically assigned hash table by their destination IP
- addresses.
- sh - Source Hashing: assigns jobs to servers through looking up
- a statically assigned hash table by their source IP addresses.
- sed - Shortest Expected Delay: assigns an incoming job to the
- server with the shortest expected delay. The expected delay that
- the job will experience is (Ci + 1) / Ui if sent to the ith
- server, in which Ci is the number of jobs on the the ith server
- and Ui is the fixed service rate (weight) of the ith server.
- nq - Never Queue: assigns an incoming job to an idle server if
- there is, instead of waiting for a fast one; if all the servers
- are busy, it adopts the Shortest Expected Delay policy to assign
- the job.
Add Comment
Please, Sign In to add comment