New SIMS Server

[GrumbleDook]

We are looking at replacing the old box as it is starting to creak a little ...

 

We have considered what other things we are likely to use it for (SIMS.net, Sims Document Server, FMS, PFM and admin printing) and we are wondering what we can get away with.

 

We are looking at planning for future developments and would like to ensure that we are not caught out ...

 

I know people argue about what is best for databases with regards to RAID, but do people prefere RAID 5-0 for MIS or just mirrored disks? It is still predominently a read optimised database.

[bossman]

We have raid 5+ for MIS server and it has proved it's worth as we have had two disk failures and both times the raid system dealt with it seamlessly all i had to do was replace the old disk.

[tosca925]

WE too use Raid 5+ on our SiMS box. Similar to bossman its saved our bacon once already.

[steve]

Been thinking about this myself today.

 

With the swap to SQL 2005, thought it might be time to update.

 

I was pondering RAID 0+1 for the database and sims files, with RAID 0 for the system.

 

Currently use RAID 5 with hot spare.

[GrumbleDook]

I'm looking at 5+1 ... mirror the system (seperate controllers) and then Raid 5 (with hot spare) for applications and database. I was partly worries about I/O of the database with SQL 2005 and have been thinking of ways of limiting the things that can go wrong ...

 

We have booked the local crew to do the migration (part of keeping our SLA) but we do not know whether it will be a straight move of what we have already got (it can be done quite soon) or whether we wait until we need to move to MS SQL 2005.

 

We will have to see ...

 

Thanks for the comments so far ... keep them coming.

[Ric_]

Theoretically you should stripe the database and then mirror the stripe because this gives the maximum performance and redundancy.

 

You should then mirror the disk with the log file... since this is written sequentially, the stripe will not improve performance - technically you don't need the mirror (only for the paranoid).

 

The OS should be mirrored for redundancy.

 

RAID5 will reduce performance.

 

Of course you could then cluster all this for availability

[kingswood]

Definitely stay clear of RAID 5- it's better if you have a lot of sequential reads but a lot slower if you write lots to the DB. I spoke to an Oracle 10g DB admin last year and they have known for years to stay clear of RAID 5- they get a lot slower performance than they would like with that configuration. Basically, I think for a DB you really need RAID 0 or 1 or some combination (10).

 

Enjoy.

[srochford]

You need to know how the database is used before you can really decide on RAID types. I've never used SIMS so I can't really comment on it but the data you need to decide is whether you read more data than you write. For many student records systems this would be the case and if this is so then you would probably benefit from RAID5 - it's better at reading data (not just sequential) because it will read some from each disc.

 

Performance monitor is your friend in this situation - look at how much data is being read and written (as an eg our student SQL server has written about 0.5Tb in the past 2 weeks and read just over 0.3Tb in the same time so RAID5 is good there) and look at the disk queues - technet has stuff on how to understand the numbers.

[djm968]

For anyone who does'nt know, SIMS.Net uses a backend MS SQL database so performance tuning should following general guidelines for any MS SQL database. For best overall performance, locate the database files (.mdf) and log files (.ldf) on separate arrays in your server to isolate potentially conflicting reads and writes.

 

To store your database files (.mdf), the best performance is gained by storing them using RAID 10 arrays. If this is too expensive, then RAID 5 is the next best bet. Each RAID array (5 or 10) should have as many physical disks in the array as the controller will support. This allows reads and writes to be performed simultaneously on each physical drive in the array, significantly boosting disk I/O.

 

To store your database log files (.ldf), the best performance is often gained by storing them using a RAID 1 (mirrored) array. This assumes that there is only a single log file on the RAID 1 array. If there is only a single log file on the RAID 1 array, the file can be written to sequentially, speeding up log writes.

[steve]

How many / what type of processors you going for Tony?

 

After reading that SQL 2005 can be licenced per physical processor (regardless of the numbers of cores) I'm tempted to go with the following:

 

2x Quad Core Xeons 2.66Ghz X5355

8Gb Ram

 

Running on W2K3 64-bit (I asked Capita and we can run 64-bit on the server)

[kylewilliamson]

Raid 1+0 would make sense. Particulary as its not all that expensive any more.

[zag]

If you do use raid 5, don't put it on the system drive, always have a seperate drive for the boot partition. Then just ghost that and keep all the sims data and program files on the raid 5 partition.

 

Personally I don't see any need for Raid on our SIMS server, if you have a good enough backup strategy its easy enough to restore with a few practice attempts.

 

Here is what I did when migrating, just create a new shared drive for the new server and swap them over or run in parallel for a while.

 

- Create the server
- Replicate the file system and data paths
- Update SIMS on both the new server and the old server to the latest point release
- Stop the SQL server and manually copy the mdf files from the old server
- Use a capita supplied program called "dbattach.exe" to detach the current database on the new server and attach the mdf files.

[NetworkGeezer]

Personally I don't see any need for Raid on our SIMS server, if you have a good enough backup strategy its easy enough to restore with a few practice attempts.

 

Famous last words

 

The point for the RAID is to provide instant failover (and performance increase in some cases). If you rely only on backups then that would mean having to go back to the previous backup and loosing a days worth of data. That's gonna make you very popluar in the admin office

[Irazmus]

Famous last words

 

The point for the RAID is to provide instant failover (and performance increase in some cases). If you rely only on backups then that would mean having to go back to the previous backup and loosing a days worth of data. That's gonna make you very popluar in the admin office

 

Exactly. We had a drive fail in our SIMS server last week and no-one even noticed (Except the librarian who was deafened by the Raid card's fault warning ^^; )

[bossman]

I stand by my previous post, nuff said.

[kylewilliamson]

Given the price of disk now, i'd go for RAID 1+0 if you can

 

Kyle