DistOS 2014W Lecture 19
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- Dynamo
- Key value-store.
- Build a distributed storage system:
- Scale
- Simple: key-value
- Highly available
- Guarantee Service Level Agreements (SLA).
- high concurrent.
- no dynamic routing.
- 0-hop DHT: means it is doe not have information when deliver packet from node to another , it has direct link to the destination
- Dynamo sacrifices consistency under certain failure scenarios.
- it has partition algorithm.
- Consistent hashing: the output range of a hash function is treated as a fixed circular space or “ring”.
- Key is linear and the nodes is partition.
- ”Virtual Nodes”: Each node can be responsible for more than one virtual node.
- Each data item is replicated at N hosts.
- “preference list”: The list of nodes that is responsible for storing a particular key.
- Sacrifice strong consistency for availability
- it work with 100 servers,it is not more big.
- Bigtable
- BigTable is a distributed storage system for managing structured data.
- Designed to scale to a very large size
- it stores the column together ,the raw is web pages and the column is the contents.
- Each pages have incoming links
- A BigTable is a sparse, distributed persistent multi-dimensional sorted map.
- it have a many columns and it is look as table.
- Each raw has arbitrary column.
- It is multi daimination map.