expand P400/512 controller RAID5 array??

[Tom Lyczko]

Hello, we are getting a DL380 with a SMART ARRAY P400/512 RAID controller to be an VMware ESX server.

One array will be two 36GB drives in RAID 1.

The second array will be three 146GB drives in RAID 5, leaving 3 slots open.

Can I easily expand the RAID 5 array by adding more disks of the same size??

Will this controller automatically know what to do when the 4th disk is added to provide more storage, or will I have to re-setup the controller etc.??

Can I have more than 4 drives in a RAID 5??

Or would I be better off going to RAID 6 when I need more than 4 drives??

This RAID array will store the VMs, I assume I'll have to have backups and there will be several hours' time for the array to rebuild upon adding the 4th disk to increase the amount of storage available.

Thank you, Tom

[Marek Nelec]

Hi Tom

1) Yes, you can easily expand RAID-5 by adding more drives of the same size

2) The controller will automatically recognize when additional drive is added, but it will not automatically provide more storage space. You will have to create new Array, or expand existing Array, using Array Configuration Utility (e.g. from SmartStart CD)

3) You can have more than 4 drives in RAID-5. HP used to recommend using RAID-6 (ADG) when you use more than 14 drives (of course you can use RAID-6 even when you use less than 14 drives, if want additional protection)

4) Yes, it will take some time to expand the array. HP states that expanding the array takes about 15 minutes per gigabyte (you may want to set expand priority to HIGH on your P400)

Keep in mind that expanding the array will not be enough to give your OS additional space. You will have to extend the logical drive after expanding the array. After extending the logical drive, the OS should see unpartitioned free space.

[Tom Lyczko]

Hello, thank you for replying.

Expanding the RAID5 would not be for the OS/system disk array, it would be for the storage partition containing virtual machine files, so your answers about expanding the array and telling the controller what to do are what I need to know and do after backing up the VMs, they can be restored, I'll check on this further with whomever we have setting up our ESX (Starter).

Thank you also for telling about the time and process for expanding the array.

Thank you, Tom