Forum Discussion

pgm10s's avatar
pgm10s
Level 5
13 years ago

Global Cluster for SQL

Hi

   We have 2 nodes  cluster as local HA  for SQL server. We would like to confiugre the Global Cluster using VVR for replication.

Now the database files are stored in 3 DG. Is it possible to configure the Global cluster using 3 DG. I only have configure the Global Cluster using only 1 DG for store the data.

Thank you.

business continuity
Cluster Server
  • Wally_Heim's avatar
    Wally_Heim
    13 years ago

    Hi pgm10s,

    Yes, you can have a GCO configuration with 3 diskgroups being replicated.  The bigger concern since you are using SQL is that SQL database and log files for a given database will need to be in the same diskgroup and same replication data set.  This is to ensure consistency between the database and SQL files.

    If your current configuration does not have the SQL database and logs in the same diskgroup, then you can always use the Flashsnap option to join the diskgroups to a single diskgroup.

    Thank you,

    Wally

  • Wally_Heim's avatar
    Wally_Heim
    Level 6
    13 years ago

    Hi pgm10s,

    Yes, you can have a GCO configuration with 3 diskgroups being replicated.  The bigger concern since you are using SQL is that SQL database and log files for a given database will need to be in the same diskgroup and same replication data set.  This is to ensure consistency between the database and SQL files.

    If your current configuration does not have the SQL database and logs in the same diskgroup, then you can always use the Flashsnap option to join the diskgroups to a single diskgroup.

    Thank you,

    Wally

  • mikebounds's avatar
    mikebounds
    Level 6
    13 years ago

    VCS can be configured with 3 DGs (this may be manually if wizard can't cope), but the problem is likely to be VVR.  The RVG you create for VVR is inside a diskgroup and therefore you would need 3 RVGs.  The volumes in each diskgroup will be consistent, but the 3 RVGs will not be consistent in async mode, meaning they are not guaranteed to be at the same point-in-time.  If the datafiles in the 3 diskgroups are from the same SQL instance then the datafiles MUST be at the same point-in-time for the data to be consistent.   This MAY work if you have 3 separate databases, each in its own diskgroup, but even then it depends on whether the 3 databases need to be in sync with each other.

    Best option is to join the diskgroups which you can do in VEA or using "vxdg join" CLI if you have an Enterprise licence (SFW Enterprise licence, not SFW for MS Enterprise Windows).

    See posts https://www-secure.symantec.com/connect/forums/where-can-i-verify-consistent-data-under-vvr and https://www-secure.symantec.com/connect/forums/one-rvg-going-constant-behind-and-dont-get-max-bandwidth-replicate-data-100 for more info on consistent data with databases.

    Mike

  • pgm10s's avatar
    pgm10s
    Level 5
    13 years ago

    Thank you very much.

    I think I must configure the 1 DG for GCO to ensure the data consistent.