Adding a New Storage Datastore to ESXI 6.5 (on an HP DL380 G7), and fixing the “Failed to create VMFS datastore – Cannot change the host configuration” error

This is part 3 of 3 in a series on adding new drives and storage to my HP DL380 G7 server and ESXi. The previous 2 parts are here, part 1 – adding new drives, and part 2 – configuring a new RAID array.

After the previous two steps were complete, the new disks are in, the new RAID array configured, the next step is to add the storage in ESXi to be available to new VMs. Here’s my starting point, almost out of space:

Right now I have 1 Datastore configured in ESXi:

To add a new Datastore in ESXi:

At this point I ran into the error ‘Failed to create VMFS datastore’:

This post with steps to fix the partition table on the newly added drives. First step was to enable the sshd service to ssh into the server:

First, use this command to find the disk id of the newly added disk. Here I can see my new disk array as it’s the one closest to 1TB, the size of the new disks:

ls -lha /vmfs/devices/disks/

This command shows the issue with the partition table on the new disk array:

 partedUtil getptbl /vmfs/devices/disks/(disk ID)

Next, use this command to reset the partition table to msdos type for the new disk array:

partedUtil setptbl /vmfs/devices/disks/(disk ID) msdos

Repeating the previous steps to add the new datastore now works, new store added:

New storage space now looks good!

Checking in iLO on the newly added disks, looks good:

Also, taking a look at fan speeds after 30mins or so, fan speeds all look good!


14 Replies to “Adding a New Storage Datastore to ESXI 6.5 (on an HP DL380 G7), and fixing the “Failed to create VMFS datastore – Cannot change the host configuration” error”

  1. Kevin!!!!!! You are the Man.. Thanks a lot. It saved my day. I got HPDL380-Gen9 with SSD drives. I never ever faced this issue before. I thought it was related to SSD drives but I was wrong. You method worked like a charm. I owe you a coffee 🙂

  2. PLease forgive and forget my previous message. I found the Disk ID.
    However I’m still stuck at the next step with
    partedUtil setptbl /vmfs/devices/disks/t10.ATA_____HGST_HUS724020ALA640__________________________PN1134P5G0L2MW msdos
    0 0 0 0
    Error: Read-only file system during write on /dev/disks/t10.ATA_____HGST_HUS724020ALA640__________________________PN1134P5G0L2MW
    WriteNewPtable: error removing gpt signatures from (/dev/disks/t10.ATA_____HGST_HUS724020ALA640__________________________PN1134P5G0L2MW)

  3. Had a similar issue but the disk partition shows unknown and you cannot setptbl . The issue turned out to be that the array (existing) was attached to a new VMware cluster as well as new physical switches. Array was set to use Jumbo frames and so was the vSwitch(es) but the physical switch was not. Setting the array and vSwitch to standard 1500 MTU corrected the issue.

  4. Hi,

    Thanks for this post, pointed me in the right direction, but I had the same issue as Gilles.

    “Error: Read-only file system during write on *”

    I fixed the issue by booting into GParted live CD, then setting the partition table as MSDOS. Failed to do it through VMware SSH, couldn’t be bothered to faff around.

    Working fine after using GParted 🙂

  5. Hi,
    my problem is this:
    via “mklabe or setptbl” I changed the partition type to “msdos” and then created a data storage. But after creating my data store the partition type automatically reset to “gpt” and doesn’t let me create another data store. Then I changed it back to “msdos” but after that my datastores that I created are gone.
    Does anyone of you have such an experience?
    I am very grateful in advance

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