Perc 4/di Raid 10 bigger drive Array question

I don't know any way to do it without moving data. If you replaced with same size drives you could in theory replace them one at a time and rebuild the array after each replacement. If you go larger I would just move the data to a USB drive or NAS and replace all at once. Of course that is what I would do anyway. Your not talking about that much data to move. Just my thoughts.

You can purchase larger (say 146 gig) drives and replace them one at a time, waiting between replacements for the array to return to optimal.
After that you can use diskpart or maybe the perc s/w to extend the partition or add a new drive in the spare space.

As a rule of thumb it is probably better to replace with the same speed drives. Regardless, make sure you have good backups before attempting anything and make sure all is optimal and functioning before the next swap.

I don't think the Perc 4/di has the ability to extend the array. You will have to check with Dell on that.

Absolutely have good backups before you attempt anything. Great add wmeerza. I just take that for granted and forget to mention it.

If you replace the larger drives 1 at a time and rebuild the extra disk space won't be usable the os won't even see it. The PERC 4/di doesn't support extending the array.  If you really wanted to you could try to create another array on the extra space, but i wouldn't suggest it. From my experience running more than 1 array on a set of drives is a bad, unstable idea. I would suggest making good verified backups then making another backup to an external hard drive. Turn the system off remove the drives and install the new drives, restart, the raid controller alarm will go off. Delete the array, create a new array, and copy the data back from the external hdd. This way  if something goes haywire the data is still safe on the original drives. Do not use the clear config option if you have other arrays on the controller.

The perc4d/i will not allow you to reconfig a MULTI-LEVEL array.  The controller is capable of expanding arrays, just not the multi-level arrays (raid 10 or 50).  This has to do with the complexity of the striping across each raid set implied by the raid 0 in those and not having redundancy at that level.  The array can be rebuilt one at a time with the larger disks and the extra space COULD be configured into a new array(s) but that would not be recommended.  Configuring multiple arrays on the same physical disk is just not a good idea.  I think the recommendation to backup or at least image everything and then recreate the array is the best solution.  

OK well since i have no open slots on the backplane this is what i might do.  Take one of the drives on of the 4 drive raid 10 arrary.  Put in a 300gig Single drive clone the arrary in question over to the new single drive.  replace the remain 3 drives wth 3 300gig scsi drives in raid 5 rebuild and the clone back from the single drive i just put into place over to the new raid 5 arrary.  then use the single drive as the hot spare for the raid 5 arrary.  Is it ok to put the exchange database on raid 5? gezz that does sound like a lot of work.

No problem with raid5 for exchange databases. Although it sounds like a bit of work it is probably your safest option. You will be taking another backup along with the clone (just to be sure).