We have 8 300GB SAS drives in a RAID5 + Spare configuration. It seems data capacity planning came up a bit short and I need more disk space. Instead of replacing drives with 600 GB models, I would like to take the Spare drive and add back to the array. Is this posible with the HP ACU without reconfiguring the entire awway and losing data?

  • As you have indicated in a comment that this is an ESXi host you need to consider the consequences of drive failure. If you get a multi drive failure, which is frighteningly common, you don't just lose the host, you lose all the virtual machines. It might make better business sense to offload one of the guests to another host, if possible. – John Gardeniers Sep 21 '12 at 22:04

Yes... This is possible. So you're saying you have 7 disks in the RAID 5 set, and want to take disk #8, which is currently a spare, and move it to become the 8th member of the RAID 5 array?

If you have the HP Array Configuration Utility (HP ACU) installed, this is very easy. There is a web-based GUI and a command-line option to handle this change. It can even be done online without taking the server down, as long as the right things are in place.

We would need to know the server model, controller type, cache configuration and operating system to be able to give specific details/actions.

A generic CLI setup using the hpacucli utility:

=> ctrl all show config

Smart Array P400 in Slot 9    (sn: P61630D9SUI2C3)

   array A (SAS, Unused Space: 0 MB)

      logicaldrive 1 (410.1 GB, RAID 1+0, OK)

      physicaldrive 1I:1:1 (port 1I:box 1:bay 1, SAS, 146 GB, OK)
      physicaldrive 1I:1:2 (port 1I:box 1:bay 2, SAS, 146 GB, OK)
      physicaldrive 1I:1:3 (port 1I:box 1:bay 3, SAS, 146 GB, OK)
      physicaldrive 1I:1:4 (port 1I:box 1:bay 4, SAS, 146 GB, OK)
      physicaldrive 2I:1:5 (port 2I:box 1:bay 5, SAS, 146 GB, OK)
      physicaldrive 2I:1:6 (port 2I:box 1:bay 6, SAS, 146 GB, OK)
      physicaldrive 2I:1:7 (port 2I:box 1:bay 7, SAS, 146 GB, OK, spare)

In this case, I could remove the spare with: ctrl slot=9 array A remove spares=all

I could then add the now unassigned disk, physicaldrive 2I:1:7, to the existing array with:

ctrl slot=9 logicaldrive 1 add drives=2I:1:7


ctrl slot=9 array A add drives=2I:1:7

The difference is that the first would add to the existing RAID 1+0 logical drive (which doesn't make sense since it's an odd-number of drives). The second would result in the array being larger and would give that array 146GB of "unused space", which could then be carved into another logical drive.

You can have different RAID levels on HP logical drives contained on the same group of disks!

In your case, the first command would just expand your RAID 5 array. In Windows, the space would become available. In Linux, it depends...

Edit: The OS is VMWare ESXi 5...

Your options are to run this from the bootable HP SmartStart CD using the GUI or you can install the HP ESXi bundles (here and here) for ESXi and get a usable hpacucli command-line interface to run from an ESXi console. It requires a reboot.

  • Thank you for the reply. The is an HP ProLiant DL380 G7 Smart Array P410i with 512MB FBWC. The OS is VMware ESXi 5.0 U1. There are a few Windows guests on here. – William Ricci Sep 21 '12 at 15:16
  • @WilliamRicci See my edit above. – ewwhite Sep 21 '12 at 15:23
  • Thank you ewwhite. I would prefer the command line utility route through ESXi. I am assuming after the unassigned disk is added, ESXi would have to be configured to use the expanded space? – William Ricci Sep 21 '12 at 16:55
  • The space will show up in your datastore manager. You'll simply be able to expand the datastore to fill the space at that point. – ewwhite Sep 21 '12 at 17:07

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