SIMs Redundancy options

[dhicks]

Hi I was wondering what mehods people use to make SIMs redundant/failover

 

All our other servers handle redundancy by being run as virtual machines and using DRBD to mirror disk volumes accross the network. The DRBD documentation reckons you can transfer between servers in under a second, although I haven't tried turning a server off to test it. From what I understand you'll need to have both servers licensed for Windows (and probably SQL server) to mirror a copy between two, even if you don't actually run one of those copies. Commercial software licenses suck, don't they?

 

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David Hicks

[Michael]

I'm surprised no one's suggested RAID1. Two hard disks mirroring each other (for those that do not know), so if one drive fails, the other takes over until you replace the faulty drive. This actually happened at one of my schools a few months ago. It saves a lot of time/hassle and is a very cost effective way of providing redundancy.

 

Ideally hardware RAID is recommend, however Windows Server 2003 (which I suspect most people will be running) supports software RAID.

[robins]

SQL Server's device files are always open so tricky to backup. Live/Standby server copying of databases is usually done by dumping and loading log backup files very regularly. This would be entirly possible with SIMS. Obviously theres more to it - your application files and services would need to exist on both servers and the clients would need to be repointed or the name/fixed IP of the standby server changed to take over from the live box in case of a handover. Indeed even the SQL logins would need to be fixed to allow users access to the standby server. There are ways of having database updates replicate to additional servers and clever techniques of sharing remote storage between different live servers but not terribly appropriate to school budgets or supported by the way SIMS is coded to talk to SQL server.

[kmount]

I'm surprised no one's suggested RAID1. Two hard disks mirroring each other (for those that do not know), so if one drive fails, the other takes over until you replace the faulty drive. This actually happened at one of my schools a few months ago. It saves a lot of time/hassle and is a very cost effective way of providing redundancy.

 

Ideally hardware RAID is recommend, however Windows Server 2003 (which I suspect most people will be running) supports software RAID.

 

I'd been thinking further outside of the box should there have been a software failure (windows being itself...) which would have been replicated.

[Abaddon]

Our SIMS server is virtualised, and we take several snapshots a day. There is also a Disaster Recovery rack that is part of the VMWare farm and is capable of running all the core servers if necessary. There is a mirrored NetApp in this rack which takes our primary snapshot (for disaster purposes) at 1am every day.

 

This covers all the requirements for us, but it wasn't exactly cheap - to be fair though, the solution was really a business continuity plan primarily.

[Linfit]

We have a cheap and cheerful solution. We have a decent laptop with a parallel SIMS install running on it on 2003 server. As part of our backup routine the sims database files are copied each night to various places on our network. First thing in the morning we plug the laptop into the network and a scheduled task uses dbattach to attach the copy of the database into the parallel system. The laptop goes home with myself or my network manager every night.

 

This gives us a fuly working SIMS server that can be set up off site if needs be; in desperation we could quickly build an ad-hoc network with staff laptops to get several people into the system; obviously we would lose a days changes but this is a small price to pay if you are planning for a major disaster where you do not have access to the site or any of the computers in it. In the bag with the laptops is a small switch and a car power supply and various leads, and we reckon we could run SIMS in the car park for several hours if needs be.

 

Its not instant fallover, but it cost a few hundred pounds for the hardware and the additional licences on our Schools Agreement.

[kmount]

How have you secured the laptop? (Encryption of sorts?)

[localzuk]

Why not use the built in replication features of SQL server just set the backup server as a replication subscriber to your primary server and set it to transactional replication which will keep it up to date as the data changes.

 

SQL Server Replication

How to Configure SQL Server Site Database Replication

 

Given that it is a simple one way replication handled entirely in the background by SQL it should not cause any issues with the SIMS software and so hopefully they would still support it.

 

Doing this is not supported by Capita, as it changes the DB Schema (there is a comment from one of their staff on the Capita SupportNet forums about it).

[Linfit]

How have you secured the laptop? (Encryption of sorts?)

 

Encrypted hard drive - it needs a usb key to boot it.

[teejay]

One thing I haven't seen mentioned is the Document Server storage folder, which you will need to get a fully working SIMS! Please check you are backing this up as its outside of the SIMS Root folder.

[Heebeejeebee]

One thing I haven't seen mentioned is the Document Server storage folder, which you will need to get a fully working SIMS! Please check you are backing this up as its outside of the SIMS Root folder.

 

I was thinking the same thing. The docstore and the DB need to be treated as a matched pair.

 

HBJB

[DMcCoy]

It's also suggested that the sims and fms databases are now restored at the same time when the salary projections are linked in personnel 7.

 

"If you are using Personnel 7.86 or later to generate Salary Projections in FMS and you need to restore your SIMS .net database, you must restore your FMS system to the same point. This will ensure that Salary Projections are calculated accurately and consistently. It is recommended that a backup of both databases is always taken at the same time to facilitate this."

[matt40k]

You can run SIMS on a load balanced MSSQL server, the files can go on a SAN, DMS is the only single point of failure, which you would have to manually fallover. I suppose because it's a HTTP server you could do it that way, again files on a SAN.