RAID/Backups/journaling file systems/live database backups/versioning - this is a big area
KevinQC has "critical data which keeps on changing every hour & thus I need a continuous back up as well as a drive ready to be replaced in case of a HDD Failure."
I don't know if this is transactional data which needs a database replication/clustering solution. For example, if a customer pays for a service and the primary database machine blue screens, the customer still need to be authenticated for a hot-standby/cluster database server. Data is not recoverable, realistically so no data loss is acceptable. Solutions to this kind of problem tend to be very database specific.
Perhaps, the data is market data, like trades and quotes. Then you not only need to preserve the "history" you have, but you also need a way to fill the gap. Often this means that a little data loss is ok, just more to fill.
Modern motherboards have built-in RAID which is really implemented by the OS. When there are OS/driver issues, this can often cause consistency errors which in turn cause performance problems.
For desktop machines, Dell or otherwise, I have abandoned RAID. Whether for the OS or for TBs of market data. Since market data can be gap-filled, I have found it to be far easier to install a bunch of disks and use robocopy/Windows Backup to make regular backups to secondary drives. This insures a clean copy (if master fails, have backup, if backup fails, copy over again.) By connecting the backup drive using a USB docking station, I can cycle through a set of backup drives. No need for them to all be identical, and I can always carry one over to another system if I need something too big for LAN speed.
RAID is great at improving uptime on servers (no flaky drivers need apply.)
Dell servers have typically use a PERC controller card which has its own memory stick and battery. This way, the OS thinks that it has either written some data or not, and the data will get really written when the drive have enough power to do it. I did demote a production server (RAIDed) to a test server (no RAID,) and I didn't see how to unRAID the RAID-1 drive without reformatting it.
People doing serious databases often uses a separate chasis such as a Dell PowerVault to house the drives and handle RAID issues. There are lots of cool things that can be done this way.
Since people are moving to blade computers, a SAN (like a separate file server in your LAN connected by a fiber channel) is getting to be a popular option. Again this is a cool topic with lots of cool things that people are doing.
Back-ups. Mirrored, logged, transported, cycled, versioning, ... Lots of good stuff.
Don't really know what you needs are.
I agree with MGookin that having matching drives is important. Ordering a third-drive and configuring it as a hot-spare is a good practice. In my experience with Dell/PERC-5, the hot-spare does not kick-in automatically. I had to do it in the PERC BIOS. It is possible that I could have done it live with Open Manage, but I didn't try.
I also agree that Windows 7 shadowing to be invaluable. (Journaled File Systems in general.) There are, however, pros and cons for certain applications. Databases can be helped or hurt depening upon configuration. Market Data really doesn't need it, and depending upon your purposes, contiguous data may be valuable.
Anyways, it is a big subject inwhich alot of smart people are earning innovating.
Hope you find the right balance.
