im ntu distributed information systems 2004 replication management -- 1 replication management...
TRANSCRIPT
![Page 1: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/1.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 11
Replication Management
Yih-Kuen Tsay
Dept. of Information Management
National Taiwan University
![Page 2: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/2.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 22
Motivations for Replication
• Performance enhancement– Client vs. server caching– Server pools– Replication of immutable vs. changing data
• Increased availability– Server failures– Network partition and disconnected operation
• Fault tolerance: guarantee correctness in spite of faults
![Page 3: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/3.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 33
General Requirements
• Replication transparency– Clients are not aware of multiple physical copies
(replicas) of an object.– Clients see one logical copy for each object.
• Consistency– Servers perform operations in a way that meets
the specification of correctness.
![Page 4: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/4.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 44
Source: G. Coulouris et al., Distributed Systems: Concepts and Design, Third Edition.
An Architecture forReplication Management
![Page 5: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/5.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 55
About the Servers
• Recoverability• State Machines
– Consist of state variables and commands– Outputs determined by the sequence of requests
processed
• Static vs. dynamic set of replica managers– Dynamic: servers may crash; new ones may join– Static: crashed servers are considered to cease
operating (possibly for an indefinite period)
![Page 6: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/6.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 66
Phases of Request Processing
• Issuance– unicast or multicast (from the front end to replica managers)
• Coordination (to ensure consistency)– FIFO ordering, causal ordering, total ordering, …
• Execution (maybe tentatively)• Agreement (to commit or abort)• Response
– From one replica manager or several replica managers to the front end
* The ordering of the phases varies for different systems.
![Page 7: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/7.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 77
Source: G. Coulouris et al., Distributed Systems: Concepts and Design, Third Edition.
Services for Process Groups
![Page 8: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/8.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 88
Source: G. Coulouris et al., Distributed Systems: Concepts and Design, Third Edition.
View-Synchronous Group Communications
![Page 9: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/9.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 99
Correctness Criteria
• Linearizability
• Sequential consistency
* Consider individual operations (instead of transactions).
![Page 10: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/10.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 1010
Linearizability
• The interleaved sequence of operations meets the specification of a single correct copy of the objects.
• The order of operations in the interleaving is consistent with the real times at which the operations occurred in the actual execution.
![Page 11: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/11.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 1111
Sequential Consistency
• The one-copy semantics of the replicated objects is respected.
• The order of operations is preserved for each client, i.e., consistent with the program order for each client.
* Every linearizable service is also sequentially consistent.
![Page 12: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/12.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 1212
Source: G. Coulouris et al., Distributed Systems: Concepts and Design, Third Edition.
Consistency is easily guaranteed if the replica managers are organized as a group
and the primary uses view-synchronous group communication to send updates.
The Primary-Backup (Passive) Model
![Page 13: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/13.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 1313
Source: G. Coulouris et al., Distributed Systems: Concepts and Design, Third Edition.
Each front end sends its requests one at a time to all replica managers using a
totally ordered multicast primitive, ensuring that all requests are processed in the
same order at all replica managers.
Active Replication
![Page 14: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/14.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 1414
The Gossip Architecture
• A framework for providing high availability of service through lazy replication
• A request normally executed at one replica
• Replicas updated by lazy exchange of gossip messages (containing most recent updates).
![Page 15: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/15.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 1515
Source: G. Coulouris et al., Distributed Systems: Concepts and Design, Third Edition.
Operations in a Gossip Service
![Page 16: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/16.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 1616
Timestamps
• Each front end keeps a vector timestamp reflecting the latest version accessed.
• The timestamp is attached to every request sent to a replica.
• Two front ends may exchange messages directly; these messages also carry timestamps.
• The merging of timestamps is done as usual.
![Page 17: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/17.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 1717
Timestamps (cont.)
• Each replica keeps a replica timestamp representing those updates it has received.
• It also keeps a value timestamp, reflecting the updates in the replicated value.
• The replica timestamp is attached to the reply to an update, while the value timestamp is attached to the reply to a query.
![Page 18: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/18.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 1818
Source: G. Coulouris et al., Distributed Systems: Concepts and Design, Third Edition.
Timestamp Propagations
![Page 19: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/19.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 1919
The Update Log
• Every update, when received by a replica, is recorded in the update log of the replica.
• Two reasons for keeping a log:– The update cannot be applied yet; it is held
back.– It is uncertain if the update has been received
by all replicas.
• The entries are sorted by timestamps.
![Page 20: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/20.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 2020
The Executed Operation Table
• The same update may arrive at a replica from a front end and in a gossip message from another replica.
• To prevent an update from being applied twice, the replica keeps a list of identifiers of the updates that have been applied so far.
![Page 21: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/21.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 2121
Source: G. Coulouris et al., Distributed Systems: Concepts and Design, Third Edition.
A Gossip Replica Manager
![Page 22: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/22.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 2222
Processing Query Requests
• A query request q carries a timestamp q.prev, reflecting the latest version of the value that the front end has seen.
• Request q can be applied (i.e., it is stable) if q.prev valueTS (the value timestamp of the replica that received q).
• Once q is applied, the replica returns the current valueTS along with the reply.
![Page 23: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/23.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 2323
Processing Update Requests
• For an update u (not a duplicate), replica i – increments the i-th element of its replica timestamp r
eplicaTS by one,– adds an entry to the log with a timestamp ts derived
from u.prev by replacing the i-th element with that of replicaTS, and
– return ts to the front end immediately.
• When the stability condition u.prev valueTS holds, update u is applied and its ts is merged with valueTS.
![Page 24: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/24.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 2424
Processing Gossip Messages
• For every gossip message received, a replica does the following:– Merge the arriving log with its own; duplicated updates
are discarded.– Apply updates that have become stable.
• A gossip message need not contain the entire log, if it is certain that some of the updates have been seen by the receiving replica.
![Page 25: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/25.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 2525
Source: G. Coulouris et al., Distributed Systems: Concepts and Design, Third Edition.
Updates in Bayou
![Page 26: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/26.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 2626
About Bayou
• Consistency guarantees
• Merging of updates
• Dependency checks
• Merge procedures
![Page 27: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/27.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 2727
Coda vs. AFS
• More general replication
• Greater tolerance toward server crashes
• Allowing disconnected operations
![Page 28: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/28.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 2828
• A replicated transactional service should appear the same as one without replicated data.
• The effects of transactions performed by various clients on replicated data are the same as if they had been performed one at a time on single data items; this property is called one-copy serializability.
Transactions with Replicated Data
![Page 29: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/29.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 2929
• Failures should be serialized with respect to transactions.
• Any failure observed by a transaction must appear to have happened before the transaction started.
Transactions withReplicated Data (cont.)
![Page 30: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/30.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 3030
Schemes for One-Copy Serializability
• Read one/write all
• Available copies replication
• Schemes that also tolerate network partitioning:– available copies with validation– quorum consensus– virtual partition
![Page 31: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/31.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 3131
Source: Instructor’s guide for G. Coulouris et al., Distributed Systems: Concepts and Design, Third Edition.
B
A
Client + front end
BB BA A
getBalance(A)
Client + front end
Replica managersReplica managers
deposit(B,3);
UT
Transactions on Replicated Data
![Page 32: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/32.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 3232
Available Copies Replication
• A client's read request on a logical data item may be performed by any available replica, but a client's update request must be performed by all available replicas.
• A local validation procedure is required to ensure that any failure or recovery does not appear to happen during the progress of a transaction.
![Page 33: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/33.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 3333
Source: Instructor’s guide for G. Coulouris et al., Distributed Systems: Concepts and Design, Third Edition.
A
X
Client + front end
P
B
Client + front end
Replica managers
deposit(A,3);
UT
deposit(B,3);
getBalance(B)
getBalance(A)
Replica managers
Y
M
B
N
A
B
Available Copies Replication (cont.)
![Page 34: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/34.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 3434
Source: G. Coulouris et al., Distributed Systems: Concepts and Design, Third Edition.
Network Partition
![Page 35: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/35.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 3535
Available Copies with Validation
• The available copies algorithm is applied within each partition.
• When a partition is repaired, the possibly conflicting transactions that took place in the separate partitions are validated.
• If the validation fails, some of the transactions have to be aborted.
![Page 36: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/36.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 3636
Quorum Consensus Methods
• One way to ensure consistency across different partitions is to make a rule that operations can only be carried out within one of the partitions.
• A quorum is a subgroup of replicas whose size gives it the right to execute operations.
• Version numbers or timestamps may be used to determine whether copies of the data item are up to date.
![Page 37: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/37.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 3737
Source: G. Coulouris et al., Distributed Systems: Concepts and Design, Third Edition.
An Example for Quorum Consensus
![Page 38: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/38.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 3838
Source: G. Coulouris et al., Distributed Systems: Concepts and Design, Third Edition.
Two Network Partitions
![Page 39: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/39.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 3939
Source: G. Coulouris et al., Distributed Systems: Concepts and Design, Third Edition.
Virtual Partition
![Page 40: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/40.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 4040
Source: G. Coulouris et al., Distributed Systems: Concepts and Design, Third Edition.
Overlapping Virtual Partitions
![Page 41: IM NTU Distributed Information Systems 2004 Replication Management -- 1 Replication Management Yih-Kuen Tsay Dept. of Information Management National Taiwan](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f205503460f94c38d4b/html5/thumbnails/41.jpg)
IM NTUIM NTU
Distributed Information Systems Distributed Information Systems 20042004 Replication ManagementReplication Management -- -- 4141
Source: G. Coulouris et al., Distributed Systems: Concepts and Design, Third Edition.
Creating Virtual Partitions