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Real-time failover server without clustering?

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Last Modified: 2012-05-06
We want to set up a real-time failover server for a critical SQL application that runs on a dedicated Windows 2003 server.  Our initial thought was to simply use SQL replication to another server, but then we learned that there are directories of accompanying application files that must be replicated as well.  We are aware of clustering, and third-party applications such as DoubleTake, but we are hoping that there may be a less expensive alternative.  Placing the files on a network storage device would work, but that still leaves a single point of failure.

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Most Valuable Expert 2014
Commented:
Clustering is really your only  option.

Even replication needs human intervention to get it back up.

You can get away with using Windows Enterprise 2003 and SQL Server Standard edition for an active passive cluster.

You only need to buy the licenses for the Active node.

As far as network storage device -- in general, it needs to be a SAN not a NAS. You need the speed to be at least 1 GBPS and direct attached.

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There are some options but nothing is cheap other than database mirroring which is not similar to the failover clustering but it will work without any manuall intervention.
There are some hardware replication options but they are very expensive too...
http://technet.microsoft.com/en-us/library/cc917680.aspx

For other than sql serves files and folders you have to loop hw replication or some file replication.
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Most Valuable Expert 2019
Most Valuable Expert 2018
Commented:
If real-time failover would be trivial to implement, Microsoft wouldn't limit it to the Enterprise Edition and the use of certified hardware. Server clustering, especially when databases like SQL are concerned, is highly complex and has its price. (The bright spot, maybe, is that since SQL 2005, a two-node cluster is supported; SQL 2000 had to be Enterprise Edition for a cluster)
The (more or less) trivial Network Load Balancing, on the other hand, has found its way even into the Web Edition of W2k3 (it was only in Windows 2000 Advanced Server before).
It's just a matter of what you need; if a failure of the server over several hours costs a lot of money, or if you need so much uptime uptime that you can't afford to take the machine offline for patching, then you need to invest into a reliable failover solution.
Ted BouskillSenior Software Developer
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Top Expert 2009

Commented:
The previous experts are 100% correct.  Clustering is very complex technology, therefore it is expensive and it is your ONLY option for real-time failover on any platform.

Author

Commented:
Thank you for the responses.  It seems that I wasn't clear with my question.  I should have emphasized that it is the data that is the issue - not the hardware.  I need to ensure that no data is lost in the event of a hardware failure.  I understand that there will be some down time during recovery, but I want the data to be replicated in real time so that when replacement hardware is put into service, the data is current.  Restoring from backup, or shadow copy, means losing changes made since the last backup.  SQL replication does what I need regarding the SQL data - but is there a better way, and what options are there for additional non-SQL data?
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Most Valuable Expert 2019
Most Valuable Expert 2018

Commented:
Since you're looking for real-time failover of the SQL services as well as file storage, then you have the option of implementing MSCS, and use a mirrored SAN as shared storage.
The MSCS would take care of a node failure, the SAN mirroring of a storage failure (the infrastructure components would obviously have to be redundant, too).
Most Valuable Expert 2014

Commented:
You may want to look at Falconstor -- it can do offsite replication of drives and realtime mirroring of your SAN.

Costs money, but then your point of failure become your SAN units.
Ted BouskillSenior Software Developer
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Top Expert 2009

Commented:
I understand your requirements, however, replication is actually a serious problem because corruption in one database can propagate to the other instantly!  Plus there is a big performance loss.  Plus there is a latency lag with synchronization that can be equivalent to transaction log backups.  Do you use transaction log backups?  That can minimize data loss.

First off, if you want to minimize loss of data due to hardware failure you should put the databases on a RAID 6 or higher array.  With top quality hardware throughput is excellent.
Ted BouskillSenior Software Developer
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Top Expert 2009

Commented:
Sometimes 'No' is the correct answer.
Ted BouskillSenior Software Developer
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Top Expert 2009

Commented:
Sometimes 'No' is the correct answer.
Ted BouskillSenior Software Developer
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Top Expert 2009

Commented:
Based on the requirement of maintaining data and application files http:#23617436 is the correct answer.

Author

Commented:
I accept as proposed by WhackAMod.  Thank you to all for input and participation.
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