ha05

© 2010 IBM Corporation

IBM Power Systems Technical University

October 18–22, 2010 — Las Vegas, NV

Power HA System Mirror for i –Geographic Mirror

Chuck Stupca


IBM Power Systems Technical University — Las Vegas, NV

Objectives

Explain IASP geographic mirroring

Describe the steps used to create a device CRG

Show how to create a geographic mirror of an IASP

Illustrate how to switch the primary location of a geographic mirror

Explain the use of detach/reattach and of geographic mirrors



Agenda

CRG overview

Device CRGs

Creating a Device CRG (GUI and green screen)

Starting a Device CRG (GUI and green screen)

Creating a Geographic Mirror Independent Disk Pool

Working with an Geographic Mirroring Independent Disk Pool

Switchable Independent Disk Pools



Cluster Control

Device CRG

Exit Program

Clustering notifies the CRG jobs for any clustering event on all nodes on which the CRG exists (in the recovery domain).

The CRG job is responsible for taking the appropriate action for the devices it controls (in its device list).

An OPTIONAL exit program can be attached to a device CRG to perform specific tasks.

Cluster Control

Device CRG

Exit Program

How device CRGs work



CRG recovery domainsA CRG recovery domain specifies the order of recovery for the nodes in the

CRG.

Primary Node There will always be a primary node designating the node which currently has

the resource active. For a device CRG, the primary node has the disks available. For an APP CRG, the application and associated TCP/IP address will be active.

Backup node The backup node sequence specifies the order of the nodes to which CRG

resources will switch. Backup node 1 (first backup) is the next node in line to become the primary for the CRG if a failover or switchover occurs.

Replicate nodeA replicate node is part of the HA structure, but can never become the primary

node for the CRG. A replicate node may designate a Disaster Recovery system at a remote location.



Cluster AS540

1.3.22.106

1.3.22.107

1.3.22.222

1.3.22.223

ITCHA4C ITCHA4A

Internal Object Internal Object

GEOMIRACTIVE

PRIMARY

GEOMIRACTIVE

BACKUP1

Device DomainAS540

Device CRG GEOMIR

ActiveITCHA4C

ActiveITCHA4A

ActiveITCHA4C

ActiveITCHA4A

Mirrored Disk

Writes

Schematic of cluster with geographic mirroring



Steps for implementing geographic mirroring

There are five main steps to create a cross site mirror HA solution

Identify the hardware to be used in the IASP or IASP group

Create an Independent ASP or IASP group

Create a cluster and define a device domain

Create a Device CRG

Create the mirror copy of the IASP



Geographic mirroring example

ITCHA4CITCHA4C ITCHA4AITCHA4A

Sys 2

MirroredIASP

Drives

Geographic-Mirroring

Production IASP

Drives

Sys 1



Geographic mirroring

Geographic Mirroring is a sub function of cross site mirroring (XSM)

XSM requires Option 41 – High Available Switchable Resources

XSM uses support provided by 5761HAS

Geographic Mirroring runs using a function called SLIC Data Portservices.

– Intended to transfer large volumes of data between a source system and a specified target systems in a cluster environment

– Will provide synchronous and asynchronous delivery



Synchronous Delivery, Synchronous Mode



Synchronous Delivery, Asynchronous Mode



Asynchronous Delivery

ITCHA4CITCHA4C ITCHA4AITCHA4A

112

Add Page to Replication List

2Add Page to

Replication List

33

Sys 2

MirroredIASP

Drives

Geo-Mirroring of IASPProduction IASP

Drives

Sys 14

Background TaskTransmits Page

4Background TaskTransmits Page

55

6Send Acknowledgement

To Background Task

6Send Acknowledgement

To Background Task



Geographic mirroring

While geographic mirroring is being performed, users can not access the mirror copy.

– Like a switchable IASP that can go between two systems, the roles of geographic mirroring can switch.

– If the production system goes down, the mirror copy will become the production copy.

Changes are guaranteed to be made in the same order

Storage management based page level replication

Geographic mirroring is logical, not physical mirroring



Logical mirroring

DASD type/size does not have to be the same

Number of units may be different

Overall size between the Production and Mirror copy can be different

Production and Mirrored copy can have different choices for protection

– None

– Mirroring

– Parity



Filling geographic mirrored disk poolsWhen the production copy reaches threshold, objects can no longer be created.When the mirrored copy reaches threshold, geographic mirroring is suspended.

Drives

Geo-Mirroring of IASPDrives

Data

Data

IASP FullIASP Full

Data LevelData Level

Data

Data



Geographic mirroring communications

The type and number of communication lines as well as their bandwidth have an effect on performance.

Consider configuring multiple communication lines to allow for the highest performance.

TCP/IP connections/addresses should be dedicated for remote IASP mirroring use only.

The volume of disk unit writes that the applications require plays a role in the performance of the geographically mirrored IASP.



Multiple geographic mirroring communication

Up to four communication interfaces on multiple adapters can be configured

SLIC data port services will spread I/O across all lines

If one line fails, the other lines will keep the geographic mirroring active

Production IASP

HSL

Drives

Sys 2

MirroredIASP

HSL

Drives

Geo-Mirroring of IASP

TCP/IP Communication Lines

Sys 1



Geographic mirroring (1 of 3)Switchable and non-switchable IASPs can be used.

Gives local and remote switchover/failover types.

Sys 3

Sys 4

MirroredIASP

HSL

DrivesGeo-Mirroring of IASP

Sys 2

Production IASP

HSL

Drives

Sys 1

RochesterRochester StewartvilleStewartville



Geographic mirroring (2 of 3)

When the production copy is made available, the mirror copy is brought to a state that allows geographic mirroring to be performed.

– The mirror copy is not accessible by user applications– Production and mirror copies are kept in sync by storage

managementWhile mirroring changes to the backup system, a recovery time out value is specified

– How long the application can wait for the response to the IO request

– The IO will be retried for the specified amount of before suspending geographic mirroring.



Geographic mirroring (3 of 3)

Production run time impacts

– System overhead

– Application delays

Use performance tools to collect data

Geographic mirroring attributes can only be changed when the IASP is varied off

If an IASP in a device CRG has geographic mirroring configured, all IASPs in the CRG must have geographic mirroring



Geographic mirroring interfaces

Cluster commands enhanced to support geographic mirroring

Cluster Management GUI– Configure device CRG with site name and SLIC data port services IP

addresses for each node in recovery domain– Display/change device CRG

Disk Management GUI – iSeries Navigator or Systems Director Navigator for i

– Configure & deconfigure geographic mirroring– Display & change geographic mirroring attributes– Suspend & resume geographic mirroring– Detach & reattach mirror copy



Create overview

Drives

APPLE#ProductionIASP

Drives

APPLE#Mirror IASP

AS540 Cluster

ITCHA4CSystem

ITCHA4ASystem

GEOMIRCRG

Geographic Mirroring

AS540 Recoveryand Device Domain



From the Cluster Resource Services display, select Work with cluster resource groups.

Creating a CRG (1 of 13)



Press the down arrow select New Device CRG.




Click Go.




Click Next.




Enter the name of the node that owns the devices as the primary node for the CRG. Tick the box to indicate that SLIC data port services will be used for this CRG (Geographic mirroring). ClickNext




Specify a site name. Select the ip address(es) to be used for data port services. Click Add.




After all data port services addresses have been added, click Next.




Indicate that a second node is to be added to the device CRG as a backup. Specify the name of the node. Tick the box to indicate that SLIC data port services will be used.




Specify a site name. Select the ip address(es) to be used for data port services. Click Add.




After all data port services addresses have been added, click Next.




Provide a name and description for the CRG. Do not choose to usean exit program. Click Next.




Choose No for specify message queue. click Next.




Select Device description from the first drop down menu, and ASPfrom the second drop down menu. Click Next.




To create a Device CRG through a CL command in green screen, useCRTCRG.

Create Cluster Resource Group (CRTCRG)

Type choices, press Enter.

Cluster . . . . . . . . . . . AS540 Name Cluster resource group . . . GEOMIR Name Cluster resource group type . *DEV *DATA, *APP, *DEV CRG exit program . . . . . . *none ____ Name, *NONE Library . . . . . . . . . . Name

User profile . . . . . . . . *none Name, *NONE Recovery domain node list: _ Node identifier . . . . . . ITCHA4C Name Node role . . . . . . . . . *PRIMARY *BACKUP, *PRIMARY, *REPLICATE Backup sequence number . . *LAST Number, *LASTSite name . . . . . . . . . K206 _____ Name, *NONEData port IP address 9.5.110.42____

+ for more values _______________ + for more values +

Bottom



Cluster . . . . . . . . . . . AS540 Name Cluster resource group . . . GEOMIR Name Cluster resource group type . *DEV *DATA, *APP, *DEV CRG exit program . . . . . . *none ____ Name, *NONE Library . . . . . . . . . . Name

User profile . . . . . . . . *none Name, *NONE Recovery domain node list: _ Node identifier . . . . . . ITCHA4C Name Node role . . . . . . . . . *PRIMARY *BACKUP, *PRIMARY, *REPLICATE Backup sequence number . . *LAST Number, *LASTSite name . . . . . . . . . K206 _____ Name, *NONEData port IP address 9.5.110.42____

+ for more values _______________ + for more values +

Bottom

Create CRG (green screen) (1 of 4)





Recovery domain node list: _ Node identifier . . . . . . ITCHA4C Name Node role . . . . . . . . . *PRIMARY *BACKUP, *PRIMARY, *REPLICATE Backup sequence number . . *LAST Number, *LASTSite name . . . . . . . . . K206 _____ Name, *NONEData port IP address 9.5.110.42____

+ for more values _______________

Node identifier . . . . . . ITCHA4A Name Node role . . . . . . . . . *BACKUP *BACKUP, *PRIMARY, *REPLICATE Backup sequence number . . *LAST Number, *LASTSite name . . . . . . . . . L203 _____ Name, *NONEData port IP address 9.10.30.34_____

+ for more values _______________

More...



Recovery domain node list: _ Node identifier . . . . . . ITCHA4C Name Node role . . . . . . . . . *PRIMARY *BACKUP, *PRIMARY, *REPLICATE Backup sequence number . . *LAST Number, *LASTSite name . . . . . . . . . K206 _____ Name, *NONEData port IP address 9.5.110.42____

+ for more values _______________

Node identifier . . . . . . ITCHA4A Name Node role . . . . . . . . . *BACKUP *BACKUP, *PRIMARY, *REPLICATE Backup sequence number . . *LAST Number, *LASTSite name . . . . . . . . . L203 _____ Name, *NONEData port IP address 9.10.30.34_____

+ for more values _______________

More...

Fill in the information for all nodes in this CRG. NOTE: All nodes in the recovery domain must be in the same device domain.

Geographic Mirroring Information






Configuration object list:Configuration object . . . . . APPLE#___ Name, *NONE Configuration object type . . *DEVD *DEVD Configuration object online . *OFFLINE *OFFLINE, *ONLINE, *PRIMARY Server takeover IP address . . *NONE

Configuration object . . . . . __________ Name, *NONE Configuration object type . . *DEVD *DEVD Configuration object online . *OFFLINE *OFFLINE, *ONLINE, *PRIMARY Server takeover IP address . . *NONE

Configuration object . . . . . *NONE Name, *NONE Configuration object type . . *DEVD *DEVD Configuration object online . *OFFLINE *OFFLINE, *ONLINE, *PRIMARY Server takeover IP address . . *NONE

More...



Configuration object list:Configuration object . . . . . APPLE#___ Name, *NONE Configuration object type . . *DEVD *DEVD Configuration object online . *OFFLINE *OFFLINE, *ONLINE, *PRIMARY Server takeover IP address . . *NONE

Configuration object . . . . . __________ Name, *NONE Configuration object type . . *DEVD *DEVD Configuration object online . *OFFLINE *OFFLINE, *ONLINE, *PRIMARY Server takeover IP address . . *NONE

Configuration object . . . . . *NONE Name, *NONE Configuration object type . . *DEVD *DEVD Configuration object online . *OFFLINE *OFFLINE, *ONLINE, *PRIMARY Server takeover IP address . . *NONE

More...

Fill in the information for all disk pools in this CRG. NOTE: device descriptions must exist for the specified disk pools on all nodes in the recovery domain.




The value of this parameter will determine whether a disk pool will be varied on upon failover/switchover.

Create CRG (green screen) (4 of 4)Create Cluster Resource Group (CRTCRG

Configuration object list: Configuration object . . . . *NONE Name, *NONE Configuration object type . . *DEVD *DEVDConfiguration object online . *OFFLINE *OFFLINE, *ONLINE, *PRIMARY Server take...........................................................

: Configuration object list (CFGOBJ) - Help :Text 'descri : :

: *OFFLINE :Failover mes : Do not vary the configuration object on and do not :

Library . : start the server takeover IP address. :: :: *ONLINE :: Vary the configuration object on and start the :: server takeover IP address. :: :: More... :: F2=Extended help F10=Move to top F12=Cancel :

F3=Exit F4= : F13=Information Assistant F20=Enlarge F24=More keys ::.........................................................:

Create Cluster Resource Group (CRTCRG

Configuration object list: Configuration object . . . . *NONE Name, *NONE Configuration object type . . *DEVD *DEVDConfiguration object online . *OFFLINE *OFFLINE, *ONLINE, *PRIMARY Server take...........................................................

: Configuration object list (CFGOBJ) - Help :Text 'descri : :

: *OFFLINE :Failover mes : Do not vary the configuration object on and do not :

Library . : start the server takeover IP address. :: :: *ONLINE :: Vary the configuration object on and start the :: server takeover IP address. :: :: More... :: F2=Extended help F10=Move to top F12=Cancel :

F3=Exit F4= : F13=Information Assistant F20=Enlarge F24=More keys ::.........................................................:



*ONLINE V6R1 enhancement

In V5R4, if the vary on of the IASP fails for any reason, the switchover/failover is cancelled and the hardware is returned to the original primary system

In V6R1, if the vary on fails, only the vary is failed –the hardware will remain at the new primary location



The Work with Cluster Resource Groups display will show the new CRG. Press the arrow next to the CRG and select properties.

Working with a CRG (1 of 6)



Select Recovery Domain.




From this display it is possible to change node roles, add nodes to or remove nodes from the recovery domain, and to edit the properties of a node in the recovery domain.




Return to the Work with Cluster Resource Groups display, press the right arrow by the CRG, and select Switchable Devices.




The next display will show the ASP device that is managed by this CRG. Select the device, and press the right arrow next to it.




From this display, you can change the value for ONLINE/*OFFLINE, and provide an ip addresses that is associated with the device.




Configuring geographic mirroring

In order to configure geographic mirroring the following conditions must exist:

– A cluster with two active nodes in the same device domain– An independent disk pool on one of the nodes in the cluster– Disk capacity on the second node that is similar in size to the

existing disk pool– An inactive CRG with the disk pool as a configuration object

and geographic mirroring site information specified– The disk pool must be varied off

All geographic mirroring functions must be performed using the Disk Management GUI



On the disk pool screen, locate the disk pool to be geographically mirrored, click on the right arrow, select Sessions, select New,Select Geographic Mirroring – Configure Geographic Mirroring.

Configure geographic mirroring-Web-based GUI (1 of 8)



Specify the name of the node that will have the mirror copy. Click Next.




Provide signon information for the system that will have the mirror copy.




Click Add Disks.




Select the disks that will be used for the mirror copy and click OK.




Click Next.




Click Finish.




Periodically refresh the display.




To start the CRG using the web-based GUI, select Work with cluster resource groups from the Cluster Resource Services display.

Start the CRG (1 of 5)



Click the right arrow next to the CRG that manages the geographically mirrored IASP.




Select Start.




The CRG Status is changed to Started.




Start Cluster Resource Group (STRCRG)


Cluster . . . . . . . . . . . . AS540 Name Cluster resource group . . . . . GEOMIR Name Exit program data . . . . . . . *SAME________________________________ ___________________________________________________________________________________________________________________________________________________________________________________________________

Bottom

Start Cluster Resource Group (STRCRG)


Cluster . . . . . . . . . . . . AS540 Name Cluster resource group . . . . . GEOMIR Name Exit program data . . . . . . . *SAME________________________________ ___________________________________________________________________________________________________________________________________________________________________________________________________

Bottom




Vary on

After the CRG has been created and started, vary on the CRG

– Vary on the production copy– The mirror copy will be processed during the vary on

When the vary on is copmplete, check the status of the production and mirror copies of the IASP

Nex, check the status of the backup node in the CRG– Active means that the mirror copy and production copy have

been synchronized and a role swap may be performed– Ineligible means that synchronization is incomplete and the

mirror copy is not ready to assume a production role



Check status using WRKCFGSTS (1 of 2)

Work with Configuration Status ITCHA4C

01/23/04 09:40:29

Position to . . . . . Starting characters

Type options, press Enter.

1=Vary on 2=Vary off 5=Work with job 8=Work with description

9=Display mode status 13=Work with APPN status...

Opt Description Status -------------Job--------------

APPLE# AVAILABLE

Bottom

Parameters or command

nn



Check status using WRKCFGSTS (2 of 2)

Work with Configuration Status ITCHA4A

01/23/04 09:42:13






APPLE# VARIED ON

Bottom




Checking IASP status (1 of 10)Geographic mirroring information is available via iSeries Navigator or web based GUI

– Not present in the default view

– Geographic mirroring categories can be manually selected.

Information available:– Geographic Mirroring

– Mode - Geographic Mirroring

– Mirror Copy State

– Mirror Copy Data State

– Auto resume Geographic Mirroring

– Mode - Geographic Mirroring

– Recovery Policy - Geographic Mirroring

– Recovery Time-out - Geographic Mirroring

– Resume Priority - Geographic Mirroring



The geographic mirroring information about the IASP is not shownon the default display format.

Checking IASP status (2 of 10)



To customize the display to show the geographic mirroring status, click the down arrow, and select Columns.




Press Go.




On the left side of the display, highlight Mirror Copy Data State, Mirror Copy State, and Mode – Geographic Mirroring. On the right side of the display, highlight Disk Pool, and click Add After.




On the left side of the display, Select Role – Geographic Mirroring. On the right side of the display select Disk Pool. Click Add After.




On the left side of the display, Select Synchronization %. On the right side of the display, select Mode - Geographic Mirroring. Click Add After.




On the left side of the display, Select Tracking Amount. On the right side of the display select Synchronization %. Click Add After.




Customization is complete. Click OK.




Expand the columns. The display is now customized to the desiredformat. However, any navigation from this display will result in the loss of customization and the previous steps will need to be repeated.




From the Work with Cluster Resource Groups display, click the right arrow, and select Switch.

Switch geographic mirror roles (1 of 5)



Click Yes on the confirmation display..




Display CRG Information

Cluster . . . . . . . . . . . . : AS540 Cluster Resource Group . . . . . : GEOMIR Reporting Node Identifier . . . : ITCHA4C Consistent Information in Cluster: *YES

Cluster Resource Group Type . . . : DeviceCluster Resource Group Status . . : Active


Cluster . . . . . . . . . . . . : AS540 Cluster Resource Group . . . . . : GEOMIR Reporting Node Identifier . . . : ITCHA4C Consistent Information in Cluster: *YES

Cluster Resource Group Type . . . : DeviceCluster Resource Group Status . . : Active

Recovery Domain Information

Node Current Preferred Site IP Identifier Status Node Role Node Role Name Address ITCHA4C Active Primary Primary K206 9.5.110.42 ITCHA4A Active Backup 1 Backup 1 L203 9.5.110.37


Node Current Preferred Site IP Identifier Status Node Role Node Role Name Address ITCHA4C Active Primary Primary K206 9.5.110.42 ITCHA4A Active Backup 1 Backup 1 L203 9.5.110.37

The CRG GEOMIR is currently active. ITCHA4C is the primary node in the recovery domain, ITCHA4A is the backup.




Change CRG Primary (CHGCRGPRI)


Cluster . . . . . . . . . . . . AS540 Name Cluster resource group . . . . . GEOMIR Name Exit program data . . . . . . .

Change CRG Primary (CHGCRGPRI)


Cluster . . . . . . . . . . . . AS540 Name Cluster resource group . . . . . GEOMIR Name Exit program data . . . . . . .


Node Current Preferred Site IP Identifier Status Node Role Node Role Name Address ITCHA4A Active Primary Backup 1 L203 9.5.110.37ITCHA4C Active Backup 1 Primary K206 9.5.48.251


Node Current Preferred Site IP Identifier Status Node Role Node Role Name Address ITCHA4A Active Primary Backup 1 L203 9.5.110.37ITCHA4C Active Backup 1 Primary K206 9.5.48.251





Cluster . . . . . . . . . . . . : AS540 Cluster Resource Group . . . . . : GEOMIR Reporting Node Identifier . . . : ITCHA4A Consistent Information in Cluster: *YES


Node Current Preferred Site IP Identifier Status Node Role Node Role Name Address ITCHA4A Active Primary Backup 1 L203 9.5.110.37 ITCHA4C Active Backup 1 Primary K206 9.5.48.251

Bottom


Cluster . . . . . . . . . . . . : AS540 Cluster Resource Group . . . . . : GEOMIR Reporting Node Identifier . . . : ITCHA4A Consistent Information in Cluster: *YES


Node Current Preferred Site IP Identifier Status Node Role Node Role Name Address ITCHA4A Active Primary Backup 1 L203 9.5.110.37 ITCHA4C Active Backup 1 Primary K206 9.5.48.251

Bottom




Managing geographic mirrors

Requires the Use of ASP Copy Descriptions and an ASP Session

For Geographic mirroring two ASP copy descriptions are used

– Production copy

– Mirror copy

The two copy descriptions are managed by the ASP Session



ASP sessionA session describes the type of XSM implementation

– Geographic mirroring

– Flash Copy

– Metro Mirror

– Global Mirror

For geographic mirroring, both ASP copy descriptions are specified

Session is used for several geographic mirror operations– Suspend

– Resume

– Detach

– Reattach

– Change attributes



ADDASPCPYD to describe the, disk pool, provide the CRG name and location name of the production copy of the geographic mirror.

ADDASPCPYD – production copy



ADDASPCPYD to describe the, disk pool, provide the CRG name and location name of the mirror copy of the geographic mirror.

ADDASPCPYD – mirror copy



STRASPSSN – geographic mirroring

Start an ASP session to manage the geographic mirror disk pool



Geographic mirror – Detach/Reattach

The mirror copy can be detached to use at the same time as the production copy

– Backups

– Data mining

Vary off the disk pool before detaching

Use a different device description for the detached IASP

All disk pools in a disk pool group are detached

Reattach will cause mirror copy to be synchronized



Detach before

Site: K206

Data Port IP:9.5.48.251

Site: L203


Geo Mirroringof IASP

GEOMIRCRG

AS540ClusterAS540Cluster

AS540 Deviceand RecoveryDomain


ITCHA4C ITCHA4A

DASD

APPLE#Production Copy IASP

DASD

APPLE#Mirror Copy IASP

Data Flow



Detach after

Site: K206


Site: L203


GEOMIRCRG


ITCHA4C ITCHA4A

DASD


DASD

APPLE#DetachedMirror Copy IASP





Detach – command line



Looking at data (1 of 4)


02/19/04 07:53:33






APPLE# AVAILABLE

Bottom


===> DSPLIB LIB(*ALL) ASPDEV(APPLE#)

F3 E it F4 P t F12 C l F23 M ti F24 M k




Display Libraries

System: ITCHA4c

Libraries: *ALL


5=Display objects in library

ASP

Opt Library Type Device Text

APPLE#PRD PROD APPLE#

QRCL00145 PROD APPLE# Reclaim storage library.

QRCY00145 PROD APPLE# Recovery Library

QRPL00145 PROD APPLE# Library for REPLACE(*YES) processing.

QSPL0145 TEST APPLE# Spool Library

QSYS00145 PROD APPLE# System Library

QSYS200145 PROD APPLE# System Library for CPI's

SYSIB00145 PROD APPLE# System Library for DB2

VPK145 PROD APPLE#

Bottom

F3=Exit F12=Cancel F17=Top F18=Bottom



Looking at data (3 of 4)Work with Configuration Status ITCHA4A

02/19/04 07:50:53






APPLE# AVAILABLE

Bottom


===> DSPLIB LIB(*ALL) ASPDEV(APPLE#) _

F3=Exit F4=Prompt F12=Cancel F23=More options F24=More keys




Display Libraries

System: ITCHA4A

Libraries: *ALL



ASP


APPLE#MIR PROD APPLE#








VPK145 PROD APPLE#

Bottom




Reattach before

Site: K206


Site: L203


GEOMIRCRG


ITCHA4C ITCHA4A

DASD


DASD

APPLE#DetachedMirror Copy IASP





Reattach after

Site: K206


Site: L203


Geo Mirroringof IASP

GEOMIRCRG


ITCHA4C ITCHA4A

DASD


DASD

APPLE#Mirror Copy IASP

Data Flow





Work with Configuration Status ITCHA4

02/19/04 07:50:53






2 APPLE# AVAILABLE

Bottom


===> _


Reattach geographic mirror




Work with Configuration Status ITCHA4A

02/19/04 07:50:53






APPLE# VARIED OFF

Bottom


===> _


Vary off completed for device APPLE#.





02/19/04 07:50:53






2 APPLE# AVAILABLE

Bottom


===> _






02/19/04 07:53:33






APPLE# AVAILABLE

Bottom


===> DSPLIB LIB(*ALL) ASPDEV(APPLE#)





Display Libraries

System: ITCHA4c

Libraries: *ALL



ASP


APPLE#PRD PROD APPLE#








VPK145 PROD APPLE#

Bottom




Reattach notification

This means that the pairs are reattached.

The data is still being synchronized.

Determine the status of the synchronization:– DSPLOG MSGID(CPI095D)

– iSeries Navigator Mirror Copy State changes from Resuming to Active.

– GEOSTAT –ALL run in SST on the source node



Geographic mirror synchronization (1 of 2) Required when:

– Mirror copy is detached/reattached

– Suspend geographic mirroring for an available disk pool

– System suspends geographic mirroring• Loss of communications & recovery time out exceeded• Mirror copy runs out of storage• Operational failure of mirror copy

– System marks mirror copy as unusable• Need for recovery detected when vary on production system• Operational failure of production copy• Target system failures that prevent normal shut down processing

of mirror copy



Geographic mirror synchronization (2 of 2)After a reattach operation the entire disk pool will be copied from the production copy to the mirror copy

– V5R3 – Full synchronization– V5R4 – Full synchronization unless

• PTF MF40053 is applied• API QYASSDMO is used to detach/reattach

– V6R1 – Partial synchronization in base iAfter a resume operation

– Virtual addresses and page ranges of objects changed in the disk pool are recorded

– By default the area to record changes is 1% of the disk space– The maximum size of the area to store changes is 1%– If the recording area does not fill, only the recorded changes are synchronized.

During Synchronization– The production copy can be used– Performance on the production copy may be impacted– The mirror copy is unusable– The mirror copy can not become the production copy



Geographic mirror synchronization (1 of 2)

Several system and disk resources are used during the synchronization of a disk pool

Proper hardware configuration and system tuning will make synchronization efficient

– Number of disk arms

– Size and speed of disk cache

– Number and speed of communication lines

– Machine pool size

– Synchronization task priority



Geographic mirror synchronization (2 of 2)

Resume/Reattach is taking too long– Usually due to synchronization, and not the Resume/Reattach

– iSeries Navigator will show resuming at a low priority

Synchronization processes default to low priority– Parameter specified when geographic mirroring configured

– Can only be changed when the disk pool is varied off

Machine Pool Size– Increase the size of the machine pool before starting the

synchronization

– The amount of extra machine pool storage is: 300 MB + .3MB x the number of disk arms in the independent disk pool.



Device CRG/geographic mirror disk pools summary

Device CRGs control the primary location geographic mirrored disk pools

Geographic mirroring provides more benefits than switched disks:– Protection from site loss– More than one copy of data

Synchronization times are a factor of system resources– Number of disk units– Number, size, and speed of disk cache– Processor CPW– Machine Pool Size

Caution should be exercised with Detach in V5R4

ha05

Documents

device crg gui

crg jobs

app crg

crg resources

primary node

iasp geographic mirroring

geographic mirrors

geographic mirroringthere