You need to buy a new server for your most critical data, the server should be able to run 24 hours a day, 7 days a week.
What are to consider?
Brand of the servers? Of course. The softwares? Sure.
These are three things that cross my mind.
If your data are important, and mostly are, than use server that support Raid, at least Raid 5.
With Raid 5, we use at least three hard disks with the same capacity (and better with the same brand and model) and configure it as one drive. If one hard disk failed, the data still can be accessible.
Without Raid 5, if you have three hard disk, and one hard disk is failed, that all the data in that hard disk will be lost. You need to rely on your latest backup and pray that restoring the data won’t be a problem.
Minor side with Raid 5 is that Raid 5 will use one hard disk capacity as it parity, so if you have three 1 TB hard disks, than the total of your capacity is only 2 TB.
And also with Raid 5 , the performance is slower.
With at least Raid 5, you will have redundancy and more capacity compare to Raid 1. There is also Raid 6 that extend the Raid 5.
Ok, now you use Raid 5 for your critical servers that should run 24 hours a day and 7 days a week.
If one hard disk failed, at least your server still able to run with slower performance.
Now, you still need to replace the failed hard disk with a new one. If your server support Hot Swap capabilities like most IBM xseries, than it should not be a problem. You just need to unplug the failed hard disk, wait for 30 seconds and plug in the new one. Total time should be less than one minute.
But, what if your server do not support Hot Swap?
You need to shutdown your server (when? ), open the server case if necessary, detach the cables, unplug the failed hard disk, then plug in the new disk, attach the cables, close the case then power it on again.
How much time do you need for that?
And you need a spare time to do it, you can’t just shutdown the server on office hours, you need to do it after office hours, or maybe before office hours or maybe on weekend?
Make sure that your servers have good support and spare parts availability.
One thing that I like the most from IBM server is their warranty and support.
While I’m working with the IBM servers, I have two mainboards problem and four failed hard disks.
The longest time it need is to replace one mainboard from the old server (very old), because they need to ship it from Singapore.
Recently I have one failed hard disk (one of the reason why I wrote this), call IBM support and describe the problem, and all they need is our machine type, serial number and the FRU of the hard disk. Then hard disk replacement already in the office in the next morning.
That what I called a good support.
If they need a month to replace a failed a broken part, that the support, the warranty is useless.
If your warranty going to expired, or already expired, you should, you must extend it. It’s not cheap, but for me, very worthed.
With IBM, you can choose 5 days support, or 7 days support. With 7 days support, if you call them on weekend, they still come.
Not sure for other brand, if they support as good as IBM. I only works with IBM brand.
Note, I’m not an employee of IBM.