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I have an ESX-server with an existing disk array which consists of 6 disks that are mirrored:

Array: A
 Interface Type: SAS
 Unused Space: 0  MB
 Status: OK
 Array Type: Data

 Logical Drive: 1
    Size: 5.5 TB
    Fault Tolerance: 1+0
    Heads: 255
    Sectors Per Track: 32
    Cylinders: 65535
    Strip Size: 256 KB
    Full Stripe Size: 768 KB
    Status: OK
    Caching:  Enabled
    Unique Identifier: 600508B1001CCC10F587A64FA478691A
    Disk Name: vmhba2:C0:T0:L1
    Mount Points: None
    Logical Drive Label: AFE806DBPBKTU0ARH2Q1RD480D
    Mirror Group 0:
       physicaldrive 2I:1:1 (port 2I:box 1:bay 1, SAS, 2 TB, OK)
       physicaldrive 2I:1:2 (port 2I:box 1:bay 2, SAS, 2 TB, OK)
       physicaldrive 2I:1:3 (port 2I:box 1:bay 3, SAS, 2 TB, OK)
    Mirror Group 1:
       physicaldrive 2I:1:4 (port 2I:box 1:bay 4, SAS, 2 TB, OK)
       physicaldrive 2I:1:5 (port 2I:box 1:bay 5, SAS, 2 TB, OK)
       physicaldrive 2I:1:6 (port 2I:box 1:bay 6, SAS, 2 TB, OK)
    Drive Type: Data

I have added two extra drives of 2 TB (exactly the same type as the 6 ones in use) and they are correctly recognized as 2I:1:7 and 2I:1:8.

How can I safely add these to the existing configuration, so that drive 7 and 8 add 2 TB to this logical drive and nothing is lost?

When using

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

I am warned that the command is not executed ("Under this environment you must use the "forced" flag to complete the operation.". Should I be worried?

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up vote 3 down vote accepted

No, you should not be worried. You can do this without trouble. Just add the PAIR of disks...

ctrl slot=2 array A add drives=2I:1:7,2I:1:8

Then grow your logical drive... (or create a new logic drive with the free space).

You can then rescan the HBA in VMware to see the new LUN size. Let us know if you have any trouble with that.

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When adding the pair, the warning did not appear indeed. However, when trying to expand the logical drive, I get the message that "the logical drive is in a state which prevents this operation from completing". The drive has the status "Transforming, 0% complete". I suppose I have to wait until this is done? – Maarten Ureel Nov 15 '13 at 13:27
You have to wait a very long time for the data to be redistributed from the 6 old disks to the new array of 8 disks. These are slow and large drives, so the process will take some time to complete. – ewwhite Nov 15 '13 at 13:44

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