Tag Archives: Datastore

Lost Path Redundancy to Storage Device

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After installing 3 new hosts, I kept getting errors for Storage Connectivity stating “Lost path redundancy to storage device naa…….”.  We had 2 fibre cards and one of the paths was being marked as down.  I spent a couple weeks troubleshooting and trying different path selection techniques.  Still, we would randomly get alerts that the redundant path has gone down.  The only fix was to reboot the host, as not even a rescan would bring the path back up.

So after some trial and error, I found a solution.  The RCA isn’t necessarily complete yet, but I believe it was a problem with the fibre switch having an outdated firmware and us using new fibre cards in our hosts.  When using the path selection of Fixed, it would randomly pick an hba to use for each datastore.  Some datastores would use path 2 and some would use path 4.

The solution I came up with was to manually set the preferred path on each datastore (we have about 40, so it was no easy task).  You go into your host configuration, choose storage, pick a datastore and go into properties.  Inside this window, select manage paths from the bottom right and you should see your HBA’s listed.  There is a column marked Preferred with an asterisk showing which hba to prefer for the datastore (see the image below).  I went through and manually set the preferred path to be hba2 instead of letting vmware pick the path. The path selection is persistent across reboot as well when setting it manually.

storage path selectionSince manually setting the preferred path, the hosts have been stable and we have not gotten any more errors about path redundancy.  This is pretty much a band aid fix but at least we are not rebooting hosts 2-3 times per week.

Unable to remove a datastore from vCenter Server Inventory

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I recently had an issue where I was unable to remove a datastore from the vCenter Server Inventory.  The datastore was grayed out and when right-clicking, had no options.  After some digging and some research in SQL, I found a way to manually do this in the vCenter database.  Every datastore is given a unique ID and can be found and removed inside of the database.

Warning: Always make a SQL backup before attempting any manual database changes.  You never know when things might break and you need to restore.

So here we go:

  1. Stop the vCenter Server Service
  2. Open SQL Management Studio
  3. Run the following against your vCenter Server database (This will give you the datastore ID):

select ID from VPX_ENTITY where name = ‘datastore_name’

  1. Now we have the ID and can remove it from the database
  2. Run the following 3 queries individually (Using the ID we got from the previous query):

delete from VPX_DS_ASSIGNMENT where DS_ID=ID;
delete from VPX_VM_DS_SPACE where DS_ID=ID;
delete from VPX_DATASTORE where ID=ID;

  1. Finally, run the following:

delete from VPX_ENTITY where ID=ID;

If you want to verify that everything went correctly, you can run the following:

select * from VPX_DS_ASSIGNMENT where DS_ID=ID;
select * from VPX_VM_DS_SPACE where DS_ID=ID;
select * from VPX_DATASTORE where ID=ID;
select * from VPX_ENTITY where ID=ID;

Now you’ve removed the datastore from the database and can start the vCenter Server Service again. If you don’t see that it has been removed, a reboot may help. I rebooted my server just to be on the safe side.

You can check out this VMware KB for more info.

Script to Add Multiple NFS Datastores to an ESXi Host

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I am sure I’m not the first admin that has needed to add an NFS datastore to multiple hosts, and usually it’s multiple datastores that are needed as well. Normally, I would go to each host, and add the storage manually via the vSphere Client.  But after doing this for quite some time, I decided I needed a better way to get this task done.  Scripting!

I have recently started to use PowerCLI to automate many of my daily tasks (Hint: more scripts to come) and decided to share the one I’ve used the most first.  The script takes an input after running, asking you to input your host name.  Inside the script, you will set the datastores you want to add to the host.  Those are the only changes that are needed when being run.  This script has saved me a great deal of man hours and some headaches.  A great advantage to scripting is that you avoid those sneaky spelling mistakes or clicking the wrong button.

The script is below here (The bold parts are what need to be changed by you):

$VMHost = (Read-Host “Please enter the name of your ESX Host you wish to configure”)

$shellObject = new-object -comobject wscript.shell
$intAnswer = $shellObject.popup(“Do you want to add the datastores?”, 0,”Add datastores – remember you must have added the hosts on the storage”,4)
If ($intAnswer -eq 6) {
Write “Creating Datastores on $VMHost…”
New-Datastore -Nfs -VMHost $VMHost -Name DatastoreName1 -Path /vol/DatastoreName1 -NfsHost 192.168.255.251
New-Datastore -Nfs -VMHost $VMHost -Name DatastoreName2 -Path /vol/DatastoreName2 -NfsHost 192.168.255.251
New-Datastore -Nfs -VMHost $VMHost -Name DatastoreName3 -Path /vol/DatastoreName3 -NfsHost 192.168.255.251
} else {
Write “Skipping Datastores on $VMHost…”
}

When running the script, you will see the following output asking you to put in your hostname:

addnfsdatastore

You will then see a successful message for each datastore added to the host. You must remember to add the host to the NFS Export share on the storage itself before completing this step.

Script courtesy of VMware PowerCLI Blog