RAC server Pools What's new in Oracle 12c? - AIOUG server pools What's new in Ora… · Otnyathra 2017 Anju Garg RAC server Pools What's new in Oracle 12c? ANJU GARG

Otnyathra 2017 Anju Garg

RAC server Pools

What's new in Oracle 12c?

ANJU GARG


About me

• Oracle Ace

• More than 14 years of experience in IT Industry

• Oracle Certified Specialist and Expert

• Independent Corporate Trainer (Oracle DBA), Author, Speaker

• Member - AIOUG, IOUG, UKOUG

• Oracle blog : http://oracleinaction.com/

• Email : [email protected]

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http://oracleinaction.com/


Agenda

• Resource Management In A Cluster – Administrator Managed configuration – Policy Managed configuration

• Policy Based Cluster Management in Oracle 11g – Server Pools – Server Assignment

• New Server Assignment • Reallocation of servers

– Benefits – Limitations in Oracle 11g

• Enhancements in Oracle 12c – Server Categorization – Extended Policy framework

• Conclusion • References • Q & A

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Resource Management In A Cluster

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Resource Management In A Cluster

• Administrator Managed configuration • Policy Managed configuration

Resource Management In A Cluster 5


Administrator Managed configuration

• Only management strategy available in releases earlier than 11g R2 • Administrator statically assigns clusterware resources to specific servers in

the cluster. • Oracle Clusterware is responsible for placing the resources on the specified

servers • Hard coupling between the resources and the servers eliminates resource

sharing . • An inflexible, manual management configuration best suited for smaller

clusters or rather static systems • Cannot scale very well in large clusters having more than 8 nodes.



Policy Managed configuration

• Introduced in Oracle Clusterware 11g release 2

• The cluster can be logically partitioned into groups of servers called server pools.

• Administrator assigns clusterware resources to Server pools whose size can change dynamically.

• Oracle Clusterware is responsible for placing the resources on the servers belonging to the specified server pool(s).

• Flexible management eliminates the need for static definitions physically assigning resources to particular nodes in the cluster.

• Best suited for larger clusters and scales very well in large clusters having more than 8 nodes.



Policy Based Cluster Management in Oracle 11g

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Server Pools

• Foundation of policy based cluster management • Logical groups of servers hosting the resources managed by Oracle

Clusterware. • Server pools can expand or shrink as requirements change by modifying the

MIN_SIZE and MAX_SIZE attributes of the server pool. • Different IMPORTANCE can be assigned to server pools • Critical workloads can be mapped to server pools of higher IMPORTANCE. • Based on available compute resources in the cluster, Oracle Clusterware will

allocate servers to server pools in order of their IMPORTANCE • Ensures that business critical workload get the compute resources necessary

to satisfy performance or availability service level agreements.

9 Policy Based Cluster Management In Oracle 11g


Server Pool Types

• Built-in pools : Created automatically with the installation of the cluster – Generic Server Pool:

• Internally managed server pool • All attributes are read-only • Hosts Admininstrator-managed resources.

– Free Server Pool: • Internally managed server pool

• IMPORTANCE attribute can be edited by the user • Contains servers that are not assigned to any other server pools.

• User-created Server Pool • Created by user

• MIN_SIZE, MAX_SIZE and IMPORTANCE attribute can be edited by the user



Server Assignment

• New Server Assignment

• Reallocation of servers



Server Assignment New Server Assignment

• New servers are assigned to server pools in the following order:

– Generic server pool

– User-created server pool

• Fill all server pools in order of importance until they meet their minimum (MIN_SIZE).

• Fill all server pools in order of importance until they meet their maximum (MAX_SIZE).

– Free server pool



Illustration-I New Server Assignment

Policy Based Cluster Management In Oracle 11g


Illustration-I

New Server Assignment Environment

• Consider a cluster having 9 servers.

• Three server pools - FrontOffice Pool, BackOffice pool and Line of Business (LOB) pool have been defined as shown.

• Currently , all the server pools are empty.




• Since FrontOffice Pool has highest IMPORTANCE (=4), and it is below its MIN_SIZE (=2) , first two servers are assigned to it so that it meets its MIN_SIZE (=2)




• BackOffice pool which is next in IMPORTANCE (=3) is allocated next server so that it meets its MIN_SIZE (=1).




• Front office pool is allocated next server so that it meets its MAX_SIZE (=3).




• Nest two servers are assigned to BackOffice pool so that it meets its MAX_SIZE (=3).




• LOB pool which is next in IMPORTANCE(=2) is allocated two servers so that it meets its MAX_SIZE (=2).




• One left over server goes to Free Pool




Recap • As servers join the cluster, they are assigned to server pools in the

following order:

– Generic server pool

– User-created server pool

Fill all server pools in order of importance until they meet their minimum (MIN_SIZE).

Fill all server pools in order of importance until they meet their maximum (MAX_SIZE).

– Free server pool



Server Assignment Reallocation of servers

• If server(s) leave the cluster, a server reallocation between pools may take place.

• If there are servers in the Free Pool

– If a server pool falls below its MAX_SIZE value, a free server is moved from the Free Pool to the affected server pool.

• Else (No free servers)

– Only if a server pool falls below its MIN_SIZE, a server reallocation will take place as follows:

• Determine the server pool having least IMPORTANCE

• If the least IMPORTANT server pool exceeds its MIN_SIZE

– Move server to deficient pool

• Else (least IMPORTANT server pool <= MIN_SIZE)

– If IMPORTANCE of least IMPORTANT server pool < deficient pool

» Move server to deficient pool even if it causes the donor pool to fall below its MIN_SIZE



Illustration-II Reallocation Of Servers

Policy Based Cluster Management In Oracle 11g



• Environment




• One server leaves FrontOffice Pool so that the pool falls below its MAX_SIZE value (=3).




• Since a server is available in Free Pool, that server is moved to FrontOffice Pool




• FrontOffice Pool meets its MAX_SIZE (=3)




• What will happen if front office pool loses another server?




• NOTHING - Since no free servers are available and FrontOffice pool still has 2 servers (=MIN_SIZE).




• What will happen if FrontOffice pool loses another server?




• If FrontOffice pool loses another server, it is left with only one server and falls below its MIN_SIZE limit of 2 servers.

• A server should be sourced from one of the other pools.

• Which pool will become the donor in this case?




• Both the BackOffice and LOB pools exceed their MIN_SIZE but LOB pool is the least IMPORTANT

• Hence, a server is moved from LOB pool to FrontOffice pool




• FrontOffice pool has 2 servers now (=MIN_SIZE).




• What happens if any of FrontOffice or BackOffice Pools fall below their MIN_SIZE?




• If any of FrontOffice or BackOffice Pools fall below their MIN_SIZE, they will get the only remaining server in the LOB pool since LOB pool

– Exceeds its MIN_SIZE

– Has Lowest IMPORTANCE




• What happens if LOB pool is empty,

– If FrontOffice pool falls below MIN_SIZE

• It can grab server(s) from BackOffice pool so as to meet its MIN_SIZE even if it requires emptying the BackOffice pool.

– If BackOffice pool falls below MIN_SIZE

• It can get at most one server to meet its MIN_SIZE (=1) from FrontOffice pool only if FrontOffice pool exceeds its MIN_SIZE




Recap If servers leave the cluster for any reason, a server reallocation may take place as follows: • If a server pool falls below its MAX_SIZE value, a free server, if available,

is moved to the affected server pool. • If there are no free servers, then server from least IMPORTANT pool may

move to the deficient pool only if it has fallen below its MIN_SIZE value.

– If the least IMPORTANT server pool exceeds its MIN_SIZE Donate server to deficient pool

– Else (least IMPORTANT server pool <= MIN_SIZE)

Donate server only if deficient pool is more IMPORTANT


Otnyathra 2017 Anju Garg Resource Management In A Cluster

Benefits

• Fast resource failover: When the number of nodes in the cluster changes, servers are reallocated online based on defined policy to satisfy workload capacity requirements.

• Dynamic capacity assignment : Server Pools can expand or shrink as requirements change.

• Guaranteed allocation of resources : Critical work will be allocated required resources preferentially as defined by the policy.

• Isolation of resources: Since server pools do not share resources, dedicated servers can be provided in a cluster for applications and databases

• Useful for future planning: Once resource requirements has been defined for expected workload, additional capacity, whenever available will be used instantaneously.

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Limitations in Oracle 11g

• All servers were assumed to be homogeneous with regard to their CPU count, physical memory and other characteristics.

– Placement of servers in server pools could not be governed by server attributes.

– Sub-optimal performance of applications executing on inadequate servers

– Administrator needed to manually map workload to servers having appropriate attributes

A burden to the administrator

Error prone

• Does not consider the fact that server requirements of applications may be different at different times of the day, week, or month.



Enhancements in Oracle 12c

Otnyathra 2017 Anju Garg Enhancements In Oracle 12c

What’s New In Oracle 12c ?

With Oracle clusterware 12c, policy based cluster management is enhanced in three important ways.

• Server Categorization

• Extended Policy framework

• Unification of policy based cluster management with QOS Management

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Server Categorization

• Enables supporting clusters with heterogeneous servers.

• Servers can be differentiated based on their attributes which can further govern placement of servers in the server pools.

• Workflow:

– Every server has a set of server configuration attributes associated with it

– Servers are further organized into particular categories based on

Role of the node (Hub / Leaf),

Server attributes and

Various conditions

– Server categories are associated with server pools so that now server pools are defined based on server attributes rather than the names of the servers

• Provides an efficient, automated mechanism to allocate compute resources to server pools based on pre-defined server attributes.

42 Enhancements In Oracle 12c


Server Categorization Server Attributes

• As Oracle Clusterware stack is started on a server, these attributes are automatically discovered and stored persistently for each server until stack is restarted on the server

• Enable Oracle Grid Infrastructure 12c to understand heterogeneous servers in the cluster



Server Categorization Server Categories

• A new clusterware object • Enables you to organize servers into particular categories. • Two internal categories are created by default

- ora.hub.category : Categorizes Hub Nodes - ora.leaf.category : Categorizes Leaf Nodes

• New user defined server categories can be created • Various attributes of server category are:

• A server can belong to multiple categories at the same time.



Server Categorization Apply Server Categories To Server Pools

• Associate Server Pools with Server Categories so that Server pools are defined based on server attributes such as number of CPUs, CPU speed, Memory etc. rather than the names of the servers.

• Applications can be assigned to the server pools so that they will run on the servers belonging to a server category.

• If a server pool loses a server, free servers of the associated category, if available, will be moved to the server pool.

• If free servers of desired category are not available, servers will be moved from another lesser IMPORTANT server pool associated with the same category .

• Provides an automated and efficient way to manage environments having varying workload requirements and servers of different capacities .



Illustration-III Server categorization

Enhancements In Oracle 12c


Illustration-III: Server Categorization

• Consider a Flex cluster having 3 hub nodes and 2 leaf nodes. • View server attributes

– Servers host01, host02 and host03 are Hub Nodes and physical memory associated with them is greater than 2000 MB

– Servers host04 and host05 are Leaf Nodes and physical memory associated with them is less than 2000 MB




• View default server categories




• List servers in the two default categories



Illustration-III : Server Categorization

Create new user defined server categories

• Small : Leaf Node and Memory < 2000

• Big : Hub Node and Memory >= 2000


Otnyathra 2017 Anju Garg Resource Management In A Cluster


• View user defined new categories

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• List servers in user defined server categories




• List categories for servers




• Create server pools and associate them with big / small server categories as follows:

Server pool Category

Bigpool Big

Smallpool Small

Testpool Small

Backuppool Big




• View server pools and associated categories:




Recap • Server categorization enables organization of servers into particular

categories by using various server attributes. • A Server pool can be associated with a category so that servers belonging

to the category are eligible to be members of the pool . • Server pools are defined based on server attributes rather than the

names of the servers • Provides an efficient, automated mechanism to manage clusters made up

of heterogeneous nodes.



Extended Policy Framework

Why ? • In Oracle clusterware earlier than 12c, the server pools could be

configured such that each of the applications is assigned to run in its own server pool.

• This configuration, however, does not consider the fact that server time requirement of some applications might be different at different times of the day, week, or month.

• Server time requirement can vary due to – An anticipated / unanticipated increase in demand for one or more

applications in the cluster. – Planned maintenance operation (a server needs to be taken down for

maintenance) – End-of-month or end-of-year changes in demand

• Though server pool properties can be changed to meet such requirements, it is very cumbersome to do by issuing one command at a time.



Extended Policy Framework Overview

• Extended Policy Framework in Oracle clusterware 12c provides the infrastructure to handle the fluctuating requirements for server time automatically by means of policies.

• Create policies corresponding to different business needs such that each policy contains exactly one definition for each server pool defined in the system.

• These policies collectively represent the cluster configuration policy set. • Different policies need to be activated at different times in accordance

with business needs. • When a policy is activated at a relevant time, configuration of server pools

is changed according to server pool definitions in the policy. • Thus server time allocated to various applications changes automatically

in accordance with changing business needs • Moreover these policies can even be changed dynamically. • A centralized policy-based approach allows you to dynamically allocate

and reallocate resources to various applications in the cluster as the demand changes.



Illustration-IV Extended Policy Framework

Enhancements In Oracle 12c


Illustration-IV: Extended Policy Framework

Environment

• User defined server pools: Bigpool, Smallpool, Testpool and Backuppool

• Our requirement is as follows:

Night




• Add Day and Night Policies

• Set the SERVER_POOL_NAMES policy set attribute to define the scope of the server pools that are controlled by the policy set.




• Set Server Pool Attributes In Day Policy




• Set Server Pool Attributes In Night Policy




• View Day Policy




• View Night Policy




• Activate day policy




• Verify that as per the day policy, • Smallpool has been assigned both the small nodes (host04,host05) • Bigpool has been assigned three big nodes (host01,host02,host03) • Testpool and Backuppool have not been assigned any servers




• Activate night policy




• Verify that as per the night policy

– Backuppool has been assigned one big node (host01) – Bigpool has been assigned two big nodes (host02,host03) – Smallpool has been assigned one small node (host05) – Testpool has been assigned one small node (host04)




• Modify the configuration of night policy so that backuppool has 2 big

servers and bigpool has 1 big server.

• Reactivate the night policy




• As per the modified night policy, one big server (host02) has been taken

away from bigpool and has been assigned to backuppool so that bigpool is

left with only one server and backuppool has 2 servers as desired.




Recap • Extended policy framework enables policies to be configured to change

pools in accordance with business needs or application demand • Different policies need to be activated at different times in accordance with

business needs. • When a policy is activated, configuration of server pools is changed

according to server pool definitions in the policy, so that server time allocated to various applications changes in accordance with changing business needs

• These policies can be changed dynamically.



Summary

• Oracle Clusterware 11g release 2 (11.2) laid the foundation of policy based cluster management by introducing server pools .

• Limitations of Policy based management in Oracle clusterware 11g R2 : – As there was no way to distinguish between types of servers, placement

of servers in server pools could not be governed by server attributes. – This configuration does not consider the fact that server requirements of

applications may be different at different times of the day, week, or month.

• Enhancements to Policy based management in Oracle clusterware 12c: – Server Categorization: Servers can be differentiated based on their

attributes which can further govern placement of servers in server pools. – Extended Policy framework: Policies can be configured to change server

pool attributes in accordance with business needs or application demand, so that pools provide the right service at the right time. The administrators can maintain a library of policies and switch between them as required.

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References

• https://docs.oracle.com/database/121/CWADD/pbmgmt.htm#CWADD91116

• http://www.oracle.com/technetwork/database/options/clustering/learnmore/policy-managed-deployments12c-twp-2338881.pdf

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https://docs.oracle.com/database/121/CWADD/pbmgmt.htm

http://www.oracle.com/technetwork/database/options/clustering/learnmore/policy-managed-deployments12c-twp-2338881.pdf










Otnyathra 2017 Anju Garg 75


ANJU GARG Email:[email protected]

Blog:http://oracleinaction.com

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RAC server Pools What's new in Oracle 12c? - AIOUG server pools What's new in Ora… · Otnyathra 2017 Anju Garg RAC server Pools What's new in Oracle 12c? ANJU GARG