Puff The Magic Wagon!

iTrader: (2)

As it says really.

Mirroring or clustering?

What costs associated?

Hardware not really an issue but full fault tolerance is the aim on a mission critical db.

Iain

Is this a windows or Linux My Sql server.

I have a Linux MySQL datavbase that I have on multiple machines using the replication feature. Real time mirroring.

Iain

Puff The Magic Wagon!

iTrader: (2)

MS SQL2000

ozzy

Puff,

Do you need to mirror for backup/disaster recovery or do you want to have 100% uptime?

Stefan

Puff The Magic Wagon!

iTrader: (2)

We intend to run a 24/7 operation with an e-commerce solution. Both need to access the database. Downtime is not permitted (other than scheduled ).

ozzy

SQL has it's own replication, but the question I'd have is how the front-end communicates with the database. If you had suplicate database servers running SQL, they will have different server names, database names, IP addresses, etc.. Either the app is designed to query either (or both), or clustering is used to provide a single entitiy to the app. There's also the question of duplicating the front-end.

We've designed a few web-solutions around .NET/Java and SQL/Oracle here, but I'd need to ask our gurus for advice on 24/7 operations.

Stefan

Puff The Magic Wagon!

iTrader: (2)

Sorry, made the point to emphasise the 24/7 aspect. We have one program, which includes a web front end, that accesses a single SQL database.

We wish to be fault tolerant so that is any component fails, it will not interfere with the running of the operation.

As you might guess, its courier related, so as we are service orientated, then we cannot afford to have unplanned for downtime, hence it needs to be as reliable as poss.

barrybudden

Going by what you have just said I think you should be looking down the road of a cluster server.

barrybudden

These people sell some good stuff, might give you a few ideas.
http://www.rtsl.com/opencontent/defa...tion=SOLUTIONS

Hanley

If you want full 24/7 uptime then you should be really looking at Clustering.

If clustering is not an option then you could consider Log Shipping (assuming you're using SQL Server 2000 Enterprise Edition)

Basically your prod db will backup the transaction log at pre-defined intervals set by you and copy it across to your standby server and restore it.

You have the added advantage that this standby server can also be a read-only copy of your db to avoid potential "accidents"

ozzy

Puff,

The lads I need to speak to are on a customers site all week. Do you know what the front-end is developed in and if this is being hosted by the customer?

Also, will the front-end be running on an MS platform (i.e. IIS)?

Stefan

ozzy

Spoke to a couple of SQL DBA's, but they say you could use SQL replication but it involves a manual changeover. They don't know anything about Windows or SQL clustering

Stefan

Nog

Neverfail??? Good s/ware.

http://us.neverfailgroup.com/products/NFFSQLS.asp


Nog

ozzy

Frpm Neverfail webiste

Which begs the question, how will your app know to switch between the active and passive servers automatically?

Perhaps Windows Clustering + SQL Cluster Services is an option

Stefan

J1nxy

Have a look at Legatos www.legato.com replistor or Co-Standby server. They do local mirroring but can also do replication and failover across WAN links. In process of implementing for Exchange and have done real-time two way WAN based replication of file services for 5000 users using replistor. Automated failover in a matter of seconds and call also fail back. You can manual fail the services over giving you the chance to do upgrades etc

Steve

NWMark

Not too sure what app/software is accessing the SQL Server but using ASP you can do the following.

Have two SQL Servers that replicate to each other so that they are both the same, obviously they will have different names, ips etc, but thats not a problem.

Then in the code that is accessing the SQL Server, initialise the link to the server at the beginning of the code or part od code that does the SQL processing you can then check whether this was a success or not. If it fails get the code to run the same initialise code but this time with the backup server details and hope this one is still up

Mark

rs

Take a look at Doubletake, we use it for DR purposes but it works well.

http://www.sunbeltsoftware.com/product.cfm?id=111

TCMY95

Neverfail works really well..expensive though at 5k per server.

We also run a cluster and up until recently it has never given us any problems. When one of the servers fails the other fails to come up properly..we have to manually stop the dns and wins on the domain and then bring the other one back up...sort of defeats the object..lol

rs

I have implemented both Neverfail & Doubletake solutions and in my opinion DT is far less hassle and cheaper.

Rich