x

Witness server version and network operation

I am doing some preliminary research on providing a mirroring solution, as part of a new project. Management don't want to make a great deal of budget available for this, so I'm being asked to shoehorn it into existing kit (of course, the project is allowed new kit!).

Essentially, the proposed server for witnessing is a lives in a different VLAN from the new home of the project servers and runs a different version of SQL Server.

A firewall enforces separation between the VLANs such that the witness is on the outside, while the project servers are on the inside. I need to know whether I can rely solely on the implicit allow-inside-to-outside rule, or whether I need to allow explicit outside-to-inside traffic (for the witness endpoint port); and whether or not I need to add special rules to prevent the firewall dropping the connection after a certain amount of time.

So, I have a couple of questions that I can't seem to find any definitive answer on. I'm hoping that they are actually faily straightforward to someone who has actually done some or all of this:

  1. Does the witness server instance have to be of the same version (not edition) as the mirrored pair (i.e. can a mirrored pair running on 2008R2 be witnessed by a 2005 or 2008 instance)?

  2. How does the TCP network traffic flow between the pair and the witness?

    1. Is it a continuous open/half-open connection, with regular traffic flow; or is it more like a 'ping' that does the full open/close each time?
2. Which server 'initiates' the connection — do the paired servers connect to/ping the witness, or does the witness connect to/ping the paired servers? Or both, depending on circumstance?
more ▼

asked May 22, 2012 at 12:48 PM in Default

jimbobmcgee gravatar image

jimbobmcgee
359 5 6 7

(comments are locked)
10|1200 characters needed characters left

2 answers: sort oldest

Answer to question 1:

Database mirroring partners are supported only by SQL Server 2005 Standard and later versions and by SQL Server 2005 Enterprise Edition and later versions.

Witnesses, in contrast, are also supported by SQL Server 2005 Workgroup and later versions and by SQL Server 2005 Express Edition and later versions.

Except during an upgrade from an earlier version of SQL Server, the server instances in a mirroring session must all be running the same version of SQL Server.

,answer to 1: Database mirroring partners are supported only by SQL Server 2005 Standard and later versions and by SQL Server 2005 Enterprise Edition and later versions.

Witnesses, in contrast, are also supported by SQL Server 2005 Workgroup and later versions and by SQL Server 2005 Express Edition and later versions.

Except during an upgrade from an earlier version of SQL Server, the server instances in a mirroring session must all be running the same version of SQL Server.

more ▼

answered May 22, 2012 at 01:22 PM

Tauseef_jan gravatar image

Tauseef_jan
51 2 2 2

(comments are locked)
10|1200 characters needed characters left

To answer #1: Yes -

Except during an upgrade from an earlier version of SQL Server, the server instances in a mirroring session must all be running the same version of SQL Server. For example, a SQL Server 2005 witness is supported when you are upgrading from a SQL Server 2005 mirroring configuration but cannot be added to an existing or new SQL Server 2008 or later mirroring configuration.

from [MSDN][1]

Sorry I'm not technically-able enough to answer the second part! :(

[1]: http://technet.microsoft.com/en-us/library/ms175191.aspx#SwHwRecommendations
more ▼

answered May 22, 2012 at 01:27 PM

Kev Riley gravatar image

Kev Riley ♦♦
53k 47 49 76

(comments are locked)
10|1200 characters needed characters left
Your answer
toggle preview:

Up to 2 attachments (including images) can be used with a maximum of 524.3 kB each and 1.0 MB total.

New code box

There's a new way to format code on the site - the red speech bubble logo will automatically format T-SQL for you. The original code box is still there for XML, etc. More details here.

Follow this question

By Email:

Once you sign in you will be able to subscribe for any updates here

By RSS:

Answers

Answers and Comments

SQL Server Central

Need long-form SQL discussion? SQLserverCentral.com is the place.

Topics:

x344
x48
x26
x7
x4

asked: May 22, 2012 at 12:48 PM

Seen: 1094 times

Last Updated: May 22, 2012 at 01:27 PM