External RAID array or replace hard drives one by one

[somedea]

I have a Proliant GL380 G4 that's getting low on disk space. This is an Exchange server, and the company wants options other than limiting file space. Would you recommend an external RAID array that I could put the mailbox store on (if possible), or should I replace the hard drives one at a time with bigger ones and let the array rebuild itself each time, until all the drives are bigger, at which point the RAID would make use of all the drive space?
Would performance would be better with bigger internal drives?
Thanks

 

[technome]

If you replace the drives one at a time, letting rebuild complete after each drive replacement, you will still need to use a utility to extend the present volume into the unused space, unless the HP controller works differently than most; there are limitations on some utilities if the array volume is also the boot partition or Dynamic.
I would replace the present disks... how much time could the older disk set have. If you have spare bays, you could use the pulled older disks as a single drive or raid 1 for the pagefile/tmp/logs, if they are fast enough or as archive storage.
Chances are the overall throughput with two arrays will slow down due to the added overhead of the newly added external array if used; also assuming it is SCSI, the SCSI channel(s) will be saturated due to the number of disks on each channel eg. On U320 channel saturation starts at 5 disks per channel, u160 at about 3 disks, which could be an issue under heavy load.

If you do use any of these utils, backup first

Diskpart.exe

http://support.microsoft.com/kb/325590

Extpart.exe (Dell)

http://support.dell.com/support/dow...dhs&releaseid=R64398&formatcnt=2&fileid=83929

Acronis Disk Director

http://www.acronis.com/homecomputing/products/diskdirector/

Paragon...

http://www.partition-manager.com/corporate/server/

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