May 8, 2012 at 3:48 am
Hi All
A question regarding the SQL 2012 High Availibility Features
I understand that in order to use the High Availibility Features that comes with SQL 2012, the Servers need to be clustered.
1. Does this mean the SQL needs to be installed as a clustered instance or does the server just need to be clistered
2. If I want to set up SQL 2012 High Availibility between 2 Servers, do they need need to be part of the same Cluster?
Thanks
Derek
May 8, 2012 at 5:21 am
You have to have a clustering service running. That's not the same thing has having a standard failover cluster. You can read a little more in the AlwaysOn FAQ.
"The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood"
- Theodore Roosevelt
Author of:
SQL Server Execution Plans
SQL Server Query Performance Tuning
May 11, 2012 at 9:13 am
derekr 43208 (5/8/2012)
Hi AllA question regarding the SQL 2012 High Availibility Features
I understand that in order to use the High Availibility Features that comes with SQL 2012, the Servers need to be clustered.
Yes they do.
derekr 43208 (5/8/2012)
1. Does this mean the SQL needs to be installed as a clustered instance or does the server just need to be clistered
SQL server is only installed as a clustered instance if using AlwaysOn Avaliability instances, there is a difference.
derekr 43208 (5/8/2012)
2. If I want to set up SQL 2012 High Availibility between 2 Servers, do they need need to be part of the same Cluster?
as above yes they do.
In summary, If you're referring to AlwaysOn HA then yes, all nodes that will participate as availability replicas must be a member of the same Windows cluster.
For an availability group configuration, SQL Server itself is not installed as a clustered resource, the availability group listener is the only resource set up as a clustered application.
Now, for an availability instance configuration this gets more complicated, it's essentially a multi node cluster with clustered instances of sql server configured for AlwaysOn HA, this can get really confusing if you don't understand the clustering topology completely
-----------------------------------------------------------------------------------------------------------
"Ya can't make an omelette without breaking just a few eggs" 😉
May 12, 2012 at 8:31 am
Perry Whittle (5/11/2012)
derekr 43208 (5/8/2012)
Hi AllA question regarding the SQL 2012 High Availibility Features
I understand that in order to use the High Availibility Features that comes with SQL 2012, the Servers need to be clustered.
Yes they do.
derekr 43208 (5/8/2012)
1. Does this mean the SQL needs to be installed as a clustered instance or does the server just need to be clisteredSQL server is only installed as a clustered instance if using AlwaysOn Avaliability instances, there is a difference.
derekr 43208 (5/8/2012)
2. If I want to set up SQL 2012 High Availibility between 2 Servers, do they need need to be part of the same Cluster?as above yes they do.
In summary, If you're referring to AlwaysOn HA then yes, all nodes that will participate as availability replicas must be a member of the same Windows cluster.
For an availability group configuration, SQL Server itself is not installed as a clustered resource, the availability group listener is the only resource set up as a clustered application.
Now, for an availability instance configuration this gets more complicated, it's essentially a multi node cluster with clustered instances of sql server configured for AlwaysOn HA, this can get really confusing if you don't understand the clustering topology completely
Thanks
Regarding Storage: Am I right in that SQL 2012 HA Features doesn't make use of shared storage?
From what I understand, it uses Failover Clustering, without the shared storage
Is this right?
Thanks
Derek
May 12, 2012 at 8:39 am
Perry Whittle (5/11/2012)
derekr 43208 (5/8/2012)
Hi AllA question regarding the SQL 2012 High Availibility Features
I understand that in order to use the High Availibility Features that comes with SQL 2012, the Servers need to be clustered.
Yes they do.
derekr 43208 (5/8/2012)
1. Does this mean the SQL needs to be installed as a clustered instance or does the server just need to be clisteredSQL server is only installed as a clustered instance if using AlwaysOn Avaliability instances, there is a difference.
Is this just for Instance protection, not Database Level protection?
derekr 43208 (5/8/2012)
2. If I want to set up SQL 2012 High Availibility between 2 Servers, do they need need to be part of the same Cluster?as above yes they do.
In summary, If you're referring to AlwaysOn HA then yes, all nodes that will participate as availability replicas must be a member of the same Windows cluster.
For an availability group configuration, SQL Server itself is not installed as a clustered resource, the availability group listener is the only resource set up as a clustered application.
Now, for an availability instance configuration this gets more complicated, it's essentially a multi node cluster with clustered instances of sql server configured for AlwaysOn HA, this can get really confusing if you don't understand the clustering topology completely
Which configuration Provides Database Level redundancy including Hardware Redundancy(Clustering)
Thanks
May 12, 2012 at 8:51 am
derekr 43208 (5/12/2012)
Regarding Storage: Am I right in that SQL 2012 HA Features doesn't make use of shared storage?From what I understand, it uses Failover Clustering, without the shared storage
Is this right?
Thanks
Derek
Yes, for AlwaysOn availability groups you have no shared storage. However, for AlwaysOn availability instances, these use clustered instances of SQL server which do have shared storage.
-----------------------------------------------------------------------------------------------------------
"Ya can't make an omelette without breaking just a few eggs" 😉
May 12, 2012 at 9:07 am
derekr 43208 (5/12/2012)
Which configuration Provides Database Level redundancy including Hardware Redundancy(Clustering)Thanks
AlwaysOn availability gropus provide redundancy at the database (or a group databases) level.
A failover cluster instance provides protection at the instance level.
-----------------------------------------------------------------------------------------------------------
"Ya can't make an omelette without breaking just a few eggs" 😉
May 12, 2012 at 9:49 am
Perry Whittle (5/12/2012)
derekr 43208 (5/12/2012)
Which configuration Provides Database Level redundancy including Hardware Redundancy(Clustering)Thanks
AlwaysOn availability gropus provide redundancy at the database (or a group databases) level.
How is this different from Mirroring/Log Shipping?
A failover cluster instance provides protection at the instance level.
Thanks
May 12, 2012 at 9:52 am
Perry Whittle (5/12/2012)
derekr 43208 (5/12/2012)
Regarding Storage: Am I right in that SQL 2012 HA Features doesn't make use of shared storage?From what I understand, it uses Failover Clustering, without the shared storage
Is this right?
Thanks
Derek
Yes, for AlwaysOn availability groups you have no shared storage. However, for AlwaysOn availability instances, these use clustered instances of SQL server which do have shared storage.
Is this right:
AlwaysOn Availability Groups: This is redundancy at the Database Level and does not require shared storage
AlwaysOn Availability Instances: This is Basically Failover Clustering in that you can failover Instances of SQL Server and this does require shared storage
Am I missing something here?
Thanks
May 12, 2012 at 10:14 am
derekr 43208 (5/12/2012)
Perry Whittle (5/12/2012)
derekr 43208 (5/12/2012)
Regarding Storage: Am I right in that SQL 2012 HA Features doesn't make use of shared storage?From what I understand, it uses Failover Clustering, without the shared storage
Is this right?
Thanks
Derek
Yes, for AlwaysOn availability groups you have no shared storage. However, for AlwaysOn availability instances, these use clustered instances of SQL server which do have shared storage.
Is this right:
AlwaysOn Availability Groups: This is redundancy at the Database Level and does not require shared storage
AlwaysOn Availability Instances: This is Basically Failover Clustering in that you can failover Instances of SQL Server and this does require shared storage
Correct, also failover cluster instances can be used with availability groups.
-----------------------------------------------------------------------------------------------------------
"Ya can't make an omelette without breaking just a few eggs" 😉
May 12, 2012 at 10:32 am
Perry Whittle (5/12/2012)
derekr 43208 (5/12/2012)
Perry Whittle (5/12/2012)
derekr 43208 (5/12/2012)
Regarding Storage: Am I right in that SQL 2012 HA Features doesn't make use of shared storage?From what I understand, it uses Failover Clustering, without the shared storage
Is this right?
Thanks
Derek
Yes, for AlwaysOn availability groups you have no shared storage. However, for AlwaysOn availability instances, these use clustered instances of SQL server which do have shared storage.
Is this right:
AlwaysOn Availability Groups: This is redundancy at the Database Level and does not require shared storage
AlwaysOn Availability Instances: This is Basically Failover Clustering in that you can failover Instances of SQL Server and this does require shared storage
Correct, also failover cluster instances can be used with availability groups.
Thanks
So I can use The HA Groups Feature, coupled with the HA Instance Feature for one BIG HA Solution ?
In this case, are we talking Shared Storage?
Thanks
May 12, 2012 at 12:18 pm
Yes, fail over cluster instances may participate as an availability replica in AlwaysOn availability groups. Think of it like this
You have a WSFC comprising of 3 nodes. You have a clustered instance of SQL server on nodes a and b, they have shared storage for the shared drives and the clustered instance runs on one node with the other as fail over partner.
You have a stand alone instance on node c, this does not have shared storage as it uses no shared disks.
You create an AlwaysOn availability group with the clustered and stand alone instances as availability replicas.
Make sense?
-----------------------------------------------------------------------------------------------------------
"Ya can't make an omelette without breaking just a few eggs" 😉
May 18, 2012 at 2:30 pm
I would move away from shared storage, now that we have SQL 2012 AlwaysOn Availability Groups.
In our organization, at least, we have had a bad experience with shared storage in SQL clusters.
If the SAN storage fails for some reason, and it has for us on several occasions, then your HA solution is bust!
With AlwaysOn Availability Groups, each cluster node has its own storage.
If you bundle all databases together as an availability group then you can have them fail over together, almost as a make-believe instance (but without server-level objects, such as jobs, logins, linked servers etc).
I think "contained databases" is a feature that takes care of the server-level settings and can be combined with AlwaysOn Avail. groups.
__________________________________________________________________________________
SQL Server 2016 Columnstore Index Enhancements - System Views for Disk-Based Tables[/url]
Persisting SQL Server Index-Usage Statistics with MERGE[/url]
Turbocharge Your Database Maintenance With Service Broker: Part 2[/url]
May 21, 2012 at 3:27 am
Marios Philippopoulos (5/18/2012)
I would move away from shared storage, now that we have SQL 2012 AlwaysOn Availability Groups.In our organization, at least, we have had a bad experience with shared storage in SQL clusters.
If the SAN storage fails for some reason, and it has for us on several occasions, then your HA solution is bust!
I think "contained databases" is a feature that takes care of the server-level settings and can be combined with AlwaysOn Avail. groups.
With AlwaysOn Availability Groups, each cluster node has its own storage.
If you bundle all databases together as an availability group then you can have them fail over together, almost as a make-believe instance (but without server-level objects, such as jobs, logins, linked servers etc).
Thanks
For the above, does each node need to be part of the same cluster?
Does SQL need to be installed as a Clustered Instance?
Does the Server just need to be clustered?
Thanks
May 21, 2012 at 4:36 am
This is already detailed in my previous replies, but
derekr 43208 (5/21/2012)
does each node need to be part of the same cluster?
For availability groups, yes, all nodes need to be part of the same Windows cluster.
derekr 43208 (5/21/2012)
Does SQL need to be installed as a Clustered Instance?
No, although you can use clustered instances if you wish, note that this does increase the complexity of the set up and will ultimately use shared storage for the nodes that participate in the clustered instance.
derekr 43208 (5/21/2012)
Does the Server just need to be clustered?
Already answered above, the servers that are to be availability replicas need to be part of the same Windows cluster
-----------------------------------------------------------------------------------------------------------
"Ya can't make an omelette without breaking just a few eggs" 😉
Viewing 15 posts - 1 through 15 (of 21 total)
You must be logged in to reply to this topic. Login to reply