Configuring consistency in asynchronous SRDF

 

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Managing SRDF

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Select SRDF management tool: Managing SRDF using Solutions Enabler SYMCLI

Select SRDF using SYMCLI task: Managing consistency protection

Select an SRDF consistency protectiontask: Consistency protection in asynchronous mode

 

 

Contents

Configuring consistency protection in asynchronous mode. 4

About this procedure. 4

About SRDF consistency. 4

Task 1:  Display SRDF groups to the local host 4

Task 2:  Create an RDF1 group and add devices. 5

Task 3:  Set group mode to asynchronous. 6

Task 4:  Set group name option. 8

Task 5:  Split and query the composite group. 8

Task 6:  Start synchronization and verify the composite group. 10

Task 7:  Enable consistency, verify, and query the composite group. 11

 


 

Configuring consistency protection in asynchronous mode

About this procedure

·    This procedure was created using Solutions Enabler version 6.1.

·    This procedure uses the following configuration:

·    Host connected to a local Symmetrix (sid 150), with

·    SRDF/A devices in SRDF (RA) groups 25 and 26

·    SRDF daemon installed (on host)

·    All SRDF groups are capable of SRDF/A operations

·    Remote Symmetrix (152)

·    This procedure is based on content in the EMC Solutions Enabler Symmetrix SRDF Family CLI Version 7.6 Product Guide.

You can download the guide from EMC Online Support (registration required): https://support.EMC.com.

About SRDF consistency

SRDF consistency preserves the dependent-write consistency of devices within a group by monitoring data propagation from source devices (R1) to their corresponding target devices (R2). If a R1 device in the consistency group cannot propagate data to its corresponding R2 device, SRDF consistency suspends data propagation from all the R1 devices in the group.

An SRDF “consistency group” is a composite group comprised of Symmetrix SRDF devices with consistency enabled. When a database is distributed across multiple Symmetrix arrays or across multiple devices within an array, devices in the consistency group act in unison to maintain database.

Task 1:     Display SRDF groups to the local host

   1. [   ]    From the SYMCLI prompt, type the symcfg list –rdfg –all -sid SID command to display the SRDF (RA) groups on the Symmetrix attached to the local host.

In the following example, N/A in the the RDFA "Flags C" column of RA groups 25 and 26 indicates these groups are not operating in async mode.

Ellipsis (…) represents omitted output:

symconfg list –rdfg –all sid 150

 

Symmetrix ID : 000190300150

 

                S Y M M E T R I X   R D F   G R O U P S              

 

    Local             Remote                   Group               RDFA Info

-------------  --------------------  -----------------------  ---------------

          LL                                      Flags  Dir  Flags  Cycle    

RA-Grp  (sec)  RA-Grp  SymmID        T    Name     LPDS  Cfg   CSRM   time  Pri

-------------  --------------------  -----------------------  -----  -----  -

 1 ( 0)    10   1 ( 0) 000190300152  D bp4         XX..  F-S   XAM-   30    33

 2 ( 1)    10   2 ( 1) 000190300152  D power1      XX..  F-S   -IS-   30    33

 3 ( 2)    10   4 ( 3) 000190300152  D power2      XX..  F-S   -IS-   30    33

 4 ( 3)    10   9 ( 8) 000190300152  D power3      XX..  F-S   -IS-   30    33

 8 ( 7)    10   8 ( 7) 000190300152  D dav3        XX..  F-S   -IS-   30    33

10 ( 9)    10  10 ( 9) 000190300180  D test        XX..  F-S   -IS-   30    33

11 ( A)    10   3 ( 2) 000190300152  D bp1         XX..  F-S   XAM-   30    33

21 (14)    10  21 (14) 000190300180  D snhe2121    XX.N  F-S   -IS-   30    33

22 (15)    10  22 (15) 000190300152  D snhi2222    XX.N  F-S   .IS-   30    33

23 (16)    10  23 (16) 000190300180  D snhe2323    XX.N  F-S   -IS-   30    33

24 (17)    10  24 (17) 000190300152  D snhi2424    XX.N  F-S   .IS-   30    33

25 (18)    10  25 (18) 000190300152  D grp25       XX..  F-S   -IS-   30    33

26 (19)    10  26 (19) 000190300152  D grp26       XX..  F-S   -IS-   30    33

30 (1D)    10  30 (1D) 000190300152  D dav1        XX..  F-S   -IS-   30    33

…………………………………………………………………………………………………………………………………………………………………………………………………………

 

Legend:

  ?                 : Unknown

  Group (T)ype      :  S = Static, D = Dynamic

  Director (C)onfig :  F-S = Fibre-Switched, F-H = Fibre-Hub

                       G = GIGE, E = ESCON, T = T3, - = N/A

  Group Flags       :

      Prevent Auto (L)ink Recovery      : X = Enabled, . = Disabled

      Prevent RAs Online Upon (P)ower On: X = Enabled, . = Disabled

      Link (D)omino                     : X = Enabled, . = Disabled

      (S)TAR mode                       : N = Normal, R = Recovery, . = OFF

  RDFA Flags        :

      (C)onsistency : X = Enabled, . = Disabled, - = N/A

      (S)tatus      : A = Active, I = Inactive, - = N/A

      (R)DFA Mode   : S = Single-session, M = MSC, - = N/A

      (M)sc Cleanup : C = MSC Cleanup required, - = N/A

Task 2:     Create an RDF1 group and add devices

                       

   1. [   ]    Type the symdg create GroupName –type rdf1 –rdf_consistency command to create a new RDF 1 device group with consistency enabled (consistency group).

To create an RDF1 consistency group named “oracle”:

symcg create oracle -type rdf1 -rdf_consistency

 

   2. [   ]    Type the symcg –cg GroupName –sid SID –rdfg GroupNumber addall command to add standard devices from the specified SRDF group to the specified device group.

To add standard devices from SRDF group 25 to device group oracle on Symmetrix 150:

symcg -cg oracle -sid 150 -rdfg 25 addall dev

 

To add standard devices from SRDF group 26 to device group oracle on Symmetrix 150:

symcg -cg oracle -sid 150 -rdfg 26 addall dev

 

 

   3. [   ]    Type the symcg list –rdf_consistency command to display composite groups with SRDF consistemcy enabled on this host.

To display the composite groups with SRDF consistency enabled on the local host:

symcg -cg oracle -sid 150 -rdfg 25 addall dev

 

The following output shows one composite group with two devices, one in each SRDF (RAG) group:

                      C O M P O S I T E    G R O U P S  

 

                                           Number of          Number of

    Name                   Type    Valid  Symms   RAGs    Devs   BCVs   VDEVs

 

    oracle                 RDF1    Yes        1      2       2      0       0

 

Task 3:     Set group mode to asynchronous

                       

   1. [   ]    Type the symrdf –cg GroupName set mode async command to enable asynchronous replication for devices in the specified group.

To enable asynchronous replication for devices in composite group oracle:

symrdf -cg oracle set mode async -noprompt

An RDF Set 'Asynchronous Mode' operation execution is in progress for composite group 'oracle'. Please wait...

 

The RDF Set 'Asynchronous Mode' operation successfully executed for composite group 'oracle'.

 

   2. [   ]    Type the symcg show GroupName command to display status and configuration information about the device group.

To display composite group oracle:

symcg show oracle

In the following output:

·        A and S entries in the Flags S and R columns indicate that SRDF/A is now active but operating in single-session mode. In single-session mode, the Symmetrix controls the SRDF/A session.

·        A period (.) in the C column indicates SRDF consistency is not enabled. When consistency is enabled, the entire composite group will be enabled for consistency protection.

·        If the links are up when the enable is performed the SRDF (RA) groups will go from single-session mode to MSC mode. In MSC mode, the SRDF daemon controls RDFA session management.

·        If the links are not up when the enable is performed, then the SRDF (RA) groups will go into MSC mode when the links are brought by an establish or resume operation.

·        You must create the composite group using the the -rdf_consistency option in order for the group to have SRDF Consistency Protection Allowed.

 

Composite Group Name:  oracle

 

  Composite Group Type                               : RDF1

  Valid                                              : Yes

  CG in PowerPath                                    : No

  CG in GNS                                          : No

  RDF Consistency Protection Allowed                 : Yes

  RDF Consistency Mode                               : NONE

  Concurrent RDF                                     : No

 

  Number of RDF (RA) Groups                          :    2

  Number of STD Devices                              :    2

  Number of CRDF STD Devices                         :    0

  Number of BCV's (Locally-associated)               :    0

  Number of VDEV's (Locally-associated)              :    0

  Number of RVDEV's (Remotely-associated VDEV)       :    0

  Number of RBCV's (Remotely-associated STD-RDF)     :    0

  Number of BRBCV's (Remotely-associated BCV-RDF)    :    0

  Number of RRBCV's (Remotely-associated RBCV)       :    0

 

  Number of Symmetrix Units (1):

    {

 

    1) Symmetrix ID                                   : 000190300150

       Microcode Version                              : 5771

       Number of STD Devices                          :    2

       Number of CRDF STD Devices                     :    0

       Number of BCV's (Locally-associated)           :    0

       Number of VDEV's (Locally-associated)          :    0

       Number of RVDEV's (Remotely-associated VDEV)   :    0

       Number of RBCV's (Remotely-associated STD_RDF) :    0

       Number of BRBCV's (Remotely-associated BCV-RDF):    0

       Number of RRBCV's (Remotely-associated RBCV)   :    0

 

       Number of RDF (RA) Groups (2):

         {

 

         1) RDF (RA) Group Number  : 25            (18)

            Remote Symmetrix ID    : 000190300152

            Microcode Version      : 5771

            Recovery RA Group      : N/A            (N/A)

            RA Group Name          : N/A

 

            STD Devices (1):

              {

              -------------------------------------------------------------------------

                                         Sym  Device    Flags    Cap

   LdevName    PdevName                  Dev  Config    Sts      CSR    (MB)

              -------------------------------------------------------------------------

    DEV001      N/A                       0232 RDF1+R-5   RW    .AS     14370

              }

 

         2) RDF (RA) Group Number  : 26            (19)

            Remote Symmetrix ID    : 000190300152

            Microcode Version      : 5771

            Recovery RA Group      : N/A            (N/A)

            RA Group Name          : N/A

 

            STD Devices (1):

              {

              -------------------------------------------------------------------------

                                         Sym  Device     Flags   Cap

    LdevName    PdevName                 Dev  Config     Sts     CSR    (MB)

              -------------------------------------------------------------------------

    DEV002      N/A                       0242 RDF1+R-5   RW    .AS     14370

              }

         }

     }

 

Legend:

  RDFA Flags:

       C(onsistency)   : X = Enabled, . = Disabled, - = N/A

       (RDFA) S(tatus) : A = Active, I = Inactive, - = N/A

       R(DFA Mode)     : S = Single-session mode, M = MSC mode, - = N/A

 

Task 4:     Set group name option

                       

   1. [   ]    This task varies depending on whether the composite group contains only asynchronous or synchronous devices, or both asynchronous and synchronous devices.

·        If the composite group conatins both asynchronous and synchronous devices, and you want to enable consistency, you must use the symcg –set –name command to associate the composite group and SRDF groups so they can be managed as a unit.

 

This step is most critical in concurrent SRDF configurations, where one leg uses synchronous RDF groups, and the other leg uses asynchronous RDF groups.

·        If your composite group will contain both synchronous devices and asynchronous devices, proceed to Step 2. [   ].

·        If your composite group contains only synchronous or asynchronous devices, skip to Task 5:.

 

   2. [   ]    Type the symcg –cg GroupName set –name Name –rdfg SID:GroupNum,GroupNum command to associate a name with the specified RDF groups.

To associate the name OracleAsynch with RDF groups 25 and 26 on SID 150:

symcg -cg oracle set -name oracleAsync -rdfg 150:25,26

 

Task 5:     Split and query the composite group

                       

   1. [   ]    Type the symrdf –cg GroupName –split command to split the devices in the specified composite group.

To split the devices in composite group oracle:

symrdf -cg oracle split -noprompt

 

An RDF 'Split' operation execution is in progress for composite group 'oracle'. Please wait...

 

    Suspend RDF link(s) for device(s) in (0150,26)..................Started.

    Suspend RDF link(s) for device(s) in (0150,25)..................Started.

    Suspend RDF link(s) for device(s) in (0150,25)..................Done.

    Suspend RDF link(s) for device(s) in (0150,26)..................Done.

    Read/Write Enable device(s) in (0150,25) on RA at target (R2)...Done.

    Read/Write Enable device(s) in (0150,26) on RA at target (R2)...Done.

    Suspend RDF link(s) for device(s) in (0150,26)..................Started.

    Suspend RDF link(s) for device(s) in (0150,26)..................Done.

 

The RDF 'Split' operation successfully executed for composite group 'oracle'.

 

   2. [   ]    Type the symrdf –cg GroupName –query -detail command to.display the state of the SRDF/A pairs for each SRDF group in the specified composite group.

To display the state of SRDF/A pairs for the SRDF groups in composite group oracle:

symrdf -cg oracle query -detail

 

Composite Group Name      :  oracle

Composite Group Type      :  RDF1

Number of Symmetrix Units :  1

Number of RDF (RA) Groups :  2

RDF Consistency Mode      :  NONE

 

RDFG Names:

    {

    RDFG Name                          : oracleAsync

    RDF Consistency Mode               : NONE

    }

 

Symmetrix ID                      : 000190300150    (Microcode Version: 5771)

Remote Symmetrix ID               : 000190300152    (Microcode Version: 5771)

RDF (RA) Group Number             : 26 (19) - oracleAsync

Star Mode                         : NO

RDFA Info:

    {

    Cycle Number                       : 0

    Session Status                     : Inactive

    Minimum Cycle Time                 : 00:00:30

    Avg Cycle Time                     : 00:00:00

    Duration of Last cycle             : 00:00:00

    Session Priority                   : 33

    Tracks not Committed to the R2 Side: 0

    Time that R2 is behind R1          : 00:00:00

    R1 Side Percent Cache In Use       :  0

    R2 Side Percent Cache In Use       :  0

    }

 

        Source (R1) View             Target (R2) View       MODES

--------------------------------  ------------------------- ----- ----------

              ST                 LI      ST                     

  Standard     A                  N       A                     

Logical  Sym   T  R1 Inv  R2 Inv  K       T  R1 Inv  R2 Inv       RDF Pair   

Device   Dev   E  Tracks Tracks   S Dev   E  Tracks  Tracks MDAC  STATE      

-------------------------------- -- ----------------------- ----- ----------

DEV002   0242 RW       0  294766 NR 0242 RW       0       0 A...   Split      

 

Symmetrix ID                      : 000190300150    (Microcode Version: 5771)

Remote Symmetrix ID               : 000190300152    (Microcode Version: 5771)

RDF (RA) Group Number             : 25 (18) - oracleAsync

Star Mode                         : NO

RDFA Info:

    {

    Cycle Number                       : 0

    Session Status                     : Inactive

    Minimum Cycle Time                 : 00:00:30

    Avg Cycle Time                     : 00:00:00

    Duration of Last cycle             : 00:00:00

    Session Priority                   : 33

    Tracks not Committed to the R2 Side: 0

    Time that R2 is behind R1          : 00:00:00

    R1 Side Percent Cache In Use       :  0

    R2 Side Percent Cache In Use       :  0

    }

 

        Source (R1) View             Target (R2) View       MODES

--------------------------------  ------------------------- ----- ----------

              ST                 LI      ST                     

  Standard     A                  N       A                     

Logical  Sym   T  R1 Inv  R2 Inv  K       T  R1 Inv  R2 Inv       RDF Pair   

Device   Dev   E  Tracks Tracks   S Dev   E  Tracks  Tracks MDAC  STATE      

-------------------------------- -- ----------------------- ----- ----------

DEV001   0232 RW       0  294784 NR 0232 RW       0       0 A...   Split      

 

Total            ------- -------            ------- -------

  Track(s)             0  589550                  0       0

  MBs                0.0 18423.4                0.0     0.0

 

Legend for MODES:

 

 M(ode of Operation): A = Async, S = Sync, E = Semi-sync, C = Adaptive Copy

 D(omino)           : X = Enabled, . = Disabled

 A(daptive Copy)    : D = Disk Mode, W = WP Mode, . = ACp off

 C(onsistency State): X = Enabled, . = Disabled, - = N/A

 

Task 6:     Start synchronization and verify the composite group

                       

   1. [   ]    Type the symrdf –cg GroupName establish command to start synchronization of the SRDF pairs in the specified composite group.

To start synchronization for devices in composite group oracle:

symrdf -cg oracle establish -noprompt

 

An RDF 'Incremental Establish' operation execution is

in progress for composite group 'oracle'. Please wait...

 

    Write Disable device(s) in (0150,26) on RA at target (R2).......Done.

    Write Disable device(s) in (0150,25) on RA at target (R2).......Done.

    Suspend RDF link(s) for device(s) in (0150,26)..................Started.

    Suspend RDF link(s) for device(s) in (0150,25)..................Done.

    Suspend RDF link(s) for device(s) in (0150,26)..................Done.

    Suspend RDF link(s) for device(s) in (0150,26)..................Started.

    Suspend RDF link(s) for device(s) in (0150,26)..................Done.

    Resume RDF link(s) for device(s) in (0150,26)...................Started.

    Resume RDF link(s) for device(s) in (0150,25)...................Started.

    Merge track tables between source and target in (0150,25).......Started.

    Devices: 0232-0241 ............................................ Merged.

    Merge track tables between source and target in (0150,26).......Started.

    Devices: 0242-0251 ............................................ Merged.

    Merge track tables between source and target in (0150,25).......Done.

    Merge track tables between source and target in (0150,26).......Done.

    Resume RDF link(s) for device(s) in (0150,25)...................Done.

    Resume RDF link(s) for device(s) in (0150,26)...................Done.

 

The RDF 'Incremental Establish' operation successfully initiated for

composite group 'oracle'.

 

   2. [   ]    Type the symrdf –cg GroupName –consistent verify -i Seconds command to check the state of the SRDF/A pairs in the specified device group at the specified intervals until all pairs are in the Consistent state.

·        SyncInProgress indicates the SRDF/A pairs are still synchronizing.

·        Consistent indicates the SRDF/A pairs have reached consistency.

 

To check the state of SRDF/A pairs in the composite group oracle every 60 seconds until all pairs are in the Consistent state:

symrdf -cg oracle -consistent verify -i 60

 

None of the devices in the group 'oracle' are in 'Consistent' state.

 

None of the devices in the group 'oracle' are in 'Consistent' state.

……………………………………………………………………………………………………………………………………………………………………………………………

Not all of the devices in the group 'oracle' are in 'Consistent' state.

 

All devices in the group 'oracle' are in 'Consistent' state.

 

Task 7:     Enable consistency, verify, and query the composite group

                       

   1. [   ]    Type the symcg –cg GroupName enable command to enable SRDF consistency protection for the composite group.

To enable SRDF consistency protection for composite group oracle:

symcg -cg oracle enable -noprompt

 

A consistency 'Enable' operation execution is

in progress for composite group 'oracle'. Please wait...

 

The consistency 'Enable' operation successfully executed for

composite group 'oracle'.

 

   2. [   ]    Type the symrdf –cg GroupName verify –cg_consistent –i Seconds command to check the state of the group at the specified intervals until it reaches the Consistent state.

To check the state of composite group oracle every 60 seconds until it reaches the Consistent state:

symcg -cg oracle enable -noprompt

 

A consistency 'Enable' operation execution is

in progress for composite group 'oracle'. Please wait...

 

The consistency 'Enable' operation successfully executed for

composite group 'oracle'.

 

   3. [   ]    Type the symrdf –cg GroupName query –detail command to display the the state of the SRDF/A pairs for each SRDF group in the specified composite group.

To display the state of SRDF/A pairs for the SRDF groups in composite group oracle:

symrdf -cg oracle query –detail

 

In the following output:

·        Consistency protection for the group is enabled

·        All SRDF/A device pairs are in the Consistent state.

·        RDFA MSC Consistency Info shows that the Consistency State of the consistency group is also Consistent, indicating that two cycle switches have occurred since all devices in each SRDF (RA) group reached the Consistent state.

 

Note:  RDFG Names information is applicable only if you enable SRDF consistency using the RDFG Name instead of using the Composite group name.

Composite Group Name      :  oracle

Composite Group Type      :  RDF1

Number of Symmetrix Units :  1

Number of RDF (RA) Groups :  2

RDF Consistency Mode      :  MSC

RDFA MSC Consistency Info:

    {

    Session Status                     : Active

    Consistency State                  : CONSISTENT

    }

 

RDFG Names:

    {

    RDFG Name                          : oracleAsync

    RDF Consistency Mode               : NONE

    }

 

 

Symmetrix ID                      : 000190300150    (Microcode Version: 5771)

Remote Symmetrix ID               : 000190300152    (Microcode Version: 5771)

RDF (RA) Group Number             : 26 (19) - oracleAsync

Star Mode                         : NO

RDFA Info:

    {

    Cycle Number                       : 8

    Session Status                     : Active - MSC

    Minimum Cycle Time                 : 00:00:30

    Avg Cycle Time                     : 00:00:31

    Duration of Last cycle             : 00:00:30

    Session Priority                   : 33

    Tracks not Committed to the R2 Side: 0

    Time that R2 is behind R1          : 00:00:56

    R1 Side Percent Cache In Use       :  0

    R2 Side Percent Cache In Use       :  0

    }

 

 

        Source (R1) View             Target (R2) View       MODES

--------------------------------  ------------------------- ----- ----------

              ST                 LI      ST                     

  Standard     A                  N       A                     

Logical  Sym   T  R1 Inv  R2 Inv  K       T  R1 Inv  R2 Inv       RDF Pair   

Device   Dev   E  Tracks Tracks   S Dev   E  Tracks  Tracks MDAC  STATE      

-------------------------------- -- ----------------------- ----- ----------

DEV002   0242 RW       0       0 RW 0242 WD       0       0 A..X   Consistent 

 

Symmetrix ID                      : 000190300150    (Microcode Version: 5771)

Remote Symmetrix ID               : 000190300152    (Microcode Version: 5771)

RDF (RA) Group Number             : 25 (18) - oracleAsync

Star Mode                         : NO

RDFA Info:

    {

    Cycle Number                       : 8

    Session Status                     : Active - MSC

    Minimum Cycle Time                 : 00:00:30

    Avg Cycle Time                     : 00:00:31

    Duration of Last cycle             : 00:00:30

    Session Priority                   : 33

    Tracks not Committed to the R2 Side: 0

    Time that R2 is behind R1          : 00:00:56

    R1 Side Percent Cache In Use       :  0

    R2 Side Percent Cache In Use       :  0

    }

 

        Source (R1) View             Target (R2) View       MODES

--------------------------------  ------------------------- ----- ----------

              ST                 LI      ST                     

  Standard     A                  N       A                     

Logical  Sym   T  R1 Inv  R2 Inv  K       T  R1 Inv  R2 Inv       RDF Pair   

Device   Dev   E  Tracks Tracks   S Dev   E  Tracks  Tracks MDAC  STATE      

-------------------------------- -- ----------------------- ----- ----------

DEV001   0232 RW       0       0 RW 0232 WD       0       0 A..X   Consistent 

 

Total            ------- -------            ------- -------

  Track(s)             0       0                  0       0

  MBs                0.0     0.0                0.0     0.0

 

Legend for MODES:

 

 M(ode of Operation): A = Async, S = Sync, E = Semi-sync, C = Adaptive Copy

 D(omino)           : X = Enabled, . = Disabled

 A(daptive Copy)    : D = Disk Mode, W = WP Mode, . = ACp off

 C(onsistency State): X = Enabled, . = Disabled, - = N/A