EMC SRDF and SQL replication

[DBADave]

I would like to clear some confusion that I have related to EMCs SRDF
solution. I understand this solution to be an EMC proprietary disk
synchronization/replication hardware technology.

I have an environment that will include 2 sites connected via high speed,
redundant WAN links. Each site will have a SQL server with a local copy of a
SQL database that must remain constantly up to date between both sites. I am
planning on implementing transactional replication between both SQL Server to
keep both copies of the DB current.

Both of these sites have the capability to perform EMC SRDF SAN replication.
I am not that familiar with SRDF, but I do know it to be a hardware based
data replication process.

How does SQL Server 2000 respond to SRDF if a SQL server's data-device
drives or log device drives reside on a logical drive that is configured for
EMC SRDF replication? I would suspect that the data replication is only up
to the file-level, but any sort of native SQL data replication would need to
be performed outside/ontop of the SRDF process. Is SQL Server compatible
with SRDF or are there any best-practices that I can reference that relate to
SQL Server (replication and other functionality) in an environment that has
SAN replication enabled?

Thanks,
Dave

[Hilary Cotter]

It is transparent to SQL Server. However SRDF will keep both arrays and
databases in sync, so why do you want to use SQL Server replication.

SRDF works on the byte level. Any byte change on a drive will be replicated
to the mirror.

Post by DBADave
I would like to clear some confusion that I have related to EMCs SRDF
solution. I understand this solution to be an EMC proprietary disk
synchronization/replication hardware technology.
I have an environment that will include 2 sites connected via high speed,
redundant WAN links. Each site will have a SQL server with a local copy of a
SQL database that must remain constantly up to date between both sites. I am
planning on implementing transactional replication between both SQL Server to
keep both copies of the DB current.
Both of these sites have the capability to perform EMC SRDF SAN replication.
I am not that familiar with SRDF, but I do know it to be a hardware based
data replication process.
How does SQL Server 2000 respond to SRDF if a SQL server's data-device
drives or log device drives reside on a logical drive that is configured for
EMC SRDF replication? I would suspect that the data replication is only up
to the file-level, but any sort of native SQL data replication would need to
be performed outside/ontop of the SRDF process. Is SQL Server compatible
with SRDF or are there any best-practices that I can reference that relate to
SQL Server (replication and other functionality) in an environment that has
SAN replication enabled?
Thanks,
Dave

[Richard S. Hale]

Dave,

Post by Hilary Cotter
It is transparent to SQL Server. However SRDF will keep both arrays and
databases in sync, so why do you want to use SQL Server replication.
SRDF works on the byte level. Any byte change on a drive will be replicated
to the mirror.

Post by DBADave
I would like to clear some confusion that I have related to EMCs SRDF
solution. I understand this solution to be an EMC proprietary disk
synchronization/replication hardware technology.
I have an environment that will include 2 sites connected via high speed,
redundant WAN links. Each site will have a SQL server with a local copy of a
SQL database that must remain constantly up to date between both sites. I am
planning on implementing transactional replication between both SQL Server to
keep both copies of the DB current.
Both of these sites have the capability to perform EMC SRDF SAN replication.
I am not that familiar with SRDF, but I do know it to be a hardware based
data replication process.
How does SQL Server 2000 respond to SRDF if a SQL server's data-device
drives or log device drives reside on a logical drive that is configured for
EMC SRDF replication? I would suspect that the data replication is only up
to the file-level, but any sort of native SQL data replication would need to
be performed outside/ontop of the SRDF process. Is SQL Server compatible
with SRDF or are there any best-practices that I can reference that relate to
SQL Server (replication and other functionality) in an environment that has
SAN replication enabled?
Thanks,
Dave

[Richard S. Hale]

Dave you should have seperate logical disks or LUNS for the data files and
the logs for SQL Server and those LUNS should be maintained across the SAN
replication to be identical at both sites at all times SQL Server replication
has other applications within a given site generally.

Post by DBADave
I would like to clear some confusion that I have related to EMCs SRDF
solution. I understand this solution to be an EMC proprietary disk
synchronization/replication hardware technology.
I have an environment that will include 2 sites connected via high speed,
redundant WAN links. Each site will have a SQL server with a local copy of a
SQL database that must remain constantly up to date between both sites. I am
planning on implementing transactional replication between both SQL Server to
keep both copies of the DB current.
Both of these sites have the capability to perform EMC SRDF SAN replication.
I am not that familiar with SRDF, but I do know it to be a hardware based
data replication process.
How does SQL Server 2000 respond to SRDF if a SQL server's data-device
drives or log device drives reside on a logical drive that is configured for
EMC SRDF replication? I would suspect that the data replication is only up
to the file-level, but any sort of native SQL data replication would need to
be performed outside/ontop of the SRDF process. Is SQL Server compatible
with SRDF or are there any best-practices that I can reference that relate to
SQL Server (replication and other functionality) in an environment that has
SAN replication enabled?
Thanks,
Dave

[Mike Epprecht (SQL MVP)]

Hi

We are using it at work. 128Gb cache on the EMC DMX's. Synchronously, but
will move to asynchronous (ASRDF) in the next few months to give better peak
handling.

The performance is incredible, we are currently SRDF'ing 0.5Tb/hour with our
line having a capacity of 19Tb/hour.
Our replication frames are 512Kb, running over 1Mb fiber frames.

It is at byte level, with intelligence to move higher data sizes when it
sees the application uses it always (SQL writes in kb blocks).

It is recommended NOT to have TempDb on SRDF........no use moving bytes for
a DB that will get re-created on startup.

Regards
--
--------------------------------
Mike Epprecht, Microsoft SQL Server MVP
Zurich, Switzerland

IM: ***@epprecht.net

MVP Program: http://www.microsoft.com/mvp

Blog: http://www.msmvps.com/epprecht/

Post by Richard S. Hale
Dave you should have seperate logical disks or LUNS for the data files and
the logs for SQL Server and those LUNS should be maintained across the SAN
replication to be identical at both sites at all times SQL Server replication
has other applications within a given site generally.

Post by DBADave
I would like to clear some confusion that I have related to EMCs SRDF
solution. I understand this solution to be an EMC proprietary disk
synchronization/replication hardware technology.
I have an environment that will include 2 sites connected via high speed,
redundant WAN links. Each site will have a SQL server with a local copy of a
SQL database that must remain constantly up to date between both sites.

I am

Post by Richard S. Hale

Post by DBADave
planning on implementing transactional replication between both SQL Server to
keep both copies of the DB current.
Both of these sites have the capability to perform EMC SRDF SAN replication.
I am not that familiar with SRDF, but I do know it to be a hardware bas

ed

Post by Richard S. Hale

Post by DBADave
data replication process.
How does SQL Server 2000 respond to SRDF if a SQL server's data-device
drives or log device drives reside on a logical drive that is configured for
EMC SRDF replication? I would suspect that the data replication is only up
to the file-level, but any sort of native SQL data replication would need to
be performed outside/ontop of the SRDF process. Is SQL Server compatible
with SRDF or are there any best-practices that I can reference that relate to
SQL Server (replication and other functionality) in an environment that has
SAN replication enabled?
Thanks,
Dave