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Posted by on Nov 22, 2014 in Infrastructure | 0 comments

Stuck at the Loading module mptsas screen

mpt2sas

 

So you’re booting vSphere up and you’re stuck at the “Loading module mptsas”

Although this isn’t common, what do you do to get around it?

Here are some possible causes

1.  Bad hard drive

2. I/O controller hardware issue

3. I/O controller firmware issue

I faced this issue recently and sure enough, as soon as I took one of the hard drives out, vSphere booted up just fine!  I ran a health check scan on the drive and the puppy was sick!

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Posted by on Nov 3, 2014 in Infrastructure, Storage, Uncategorized | 0 comments

VSAN and Jumbo Frames

yuno

Error Message:

Call “FileManager.MakeDirectory” for object “FileManager” on vCenter Server “vCenter” failed. Failed to connect to component host 5419e4e5-daed-b7e8-3a07-00266cf65634. An unknown error has occurred. Call “FileManager.MakeDirectory” for object “FileManager” on vCenter Server “vCenter” failed. Failed to connect to component host 53229f42-40ff-aa65-8444-00266cf89748

 

Do you know the feeling of when you experience a real awesome technology and you become so excited you just can’t hide it? Yeah..so for me that is VMware’s VSAN.  I was an early adopter of VSAN and grabbed onto those beta bits as soon as it hit the wire.  During the beta it was advised to use Jumbo Frames (aka increasing the MTU size past 1500) for best performance.  I took the bait and why not? It was an easy enough to setup.

This past weekend, I migrated my VSAN cluster over to a Dell PowerConnect 6248 Layer 3 switch.  There are two places to configure Jumbo Frames on the Dell Powerconnect: The VLAN and the physical interface.

To recap, I have set:

  1. 9000 MTU on the VSAN VMkernel on the vSphere host.
  2. 9000 MTU on the VSAN VLAN on the Dell PowerConnect
  3. 9000 MTU on the VSAN Physical Interface the Dell PowerConnect

Lastly, I tested VSAN out by writing a folder to the VSAN datastore but get returned a nasty error which read

Call “FileManager.MakeDirectory” for object “FileManager” on vCenter Server “vCenter” failed. Failed to connect to component host 5419e4e5-daed-b7e8-3a07-00266cf65634. An unknown error has occurred. Call “FileManager.MakeDirectory” for object “FileManager” on vCenter Server “vCenter” failed. Failed to connect to component host 53229f42-40ff-aa65-8444-00266cf89748

 

Great, now I can’t even write a folder to the VSAN datastore so I figuratively yell into the sky, Come on VSAN Gods! Why!??

Once I got over the self pity stage, I noticed Dell uses a different type of MTU logic on the physical switch interface.  While in the rest of the world, when you configure a MTU of 9000, you mean it.  However, with Dell switches a MTU 9000 is actually (9 * 1024) = 9216.  Ugh, so now I have set

  1. 9000 MTU on the VSAN VMkernel on the vSphere host.
  2. 9000 MTU on the VSAN VLAN on the Dell PowerConnect
  3. 9216 MTU on the VSAN Physical Interface the Dell PowerConnect

BAM! The VSAN datastore is rocking and I can now write to it.  However, this scenario posed some reflection on how MTU actually impacts VSAN.  I did some further testing and came up with the follow conclusions:

  1. If any host in a VSAN cluster has a mismatched MTU size, NOTHING can write to the VSAN datastore. Even if one host with the wrong MTU is set then it will prevent VSAN from working.
  2.  Even with mismatched MTU’s when one verifies the Network Status (vCenter > Virtual SAN > General) it will show Normal. However, this doesn’t verify MTU, just IP connectivity.  To test if the MTU is correct then use the MTU of the VSAN VMkernel’s MTU size and issue a vmkping -s <VSANvmkernel_mtu_setting> <Other-VSANvmkernel-interfaces-in-cluster>
  3. VSAN performances about the same with or without Jumbo Frames configured.

In conclusion, would I advise configuring Jumbo Frames with VSAN?  No.  Unless you’re the type who prefers all risk and no reward…

 

 

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Posted by on Nov 2, 2014 in Infrastructure, Networking | 0 comments

Increasing the number vNetwork Distributed Switch (vDS) Uplink Ports

“Call “HostNetworkSystem.UpdateNetworkConfig” for object “networkSystem-27” on vCenter Server “vCenter” failed.  Network configuration change disconnected the host ‘x.x.x.x’ from vCenter server and has been rolled back.  A change in the network configuration disconnected the host ‘x.x.x.x’ from vCenter Server. The change has been rolled back.”

Let me guess, were you adding a host to a vDS and all of sudden you received this cryptic message?  If so, you may have ran out of vDS uplink ports. You may be reflecting on why you were so ungenerous to my vDS uplink port allocation in the first place?  Unfortunately I can’t answer that but I can tell you how to fix it!

Running out of vDS uplink ports will put the breaks on adding anymore hosts to your vDS.  However,  it is down right embarrassing when you find out that you can’t increase the number of ports through vCenter.  This bad boy parameter is all grayed.  WHAT!

vds1

 

When this occurred to me, I made a mad rush to Google and realized I couldn’t locate any steps to increase the number of uplink ports.  I was disappointed when I came to realization that I was the only stingy vDS uplink port allocator on the entire World Wide Web.  Or maybe I am just inefficient with my Google search engine expressions.

Regardless, I captured below on how you can get out of this sticky situation:

  1. In a web browser, go to http://vCenterServer-ip-address/mob/
  2. When prompted, enter your vCenter Server username and password.
  3. Click the content link.
  4. In the left pane, search for the row with the word rootFolder.
  5. Open the link in the right pane of the row. The link is similar to group-d1 (Datacenters).
  6. In the left pane, search for the row with the word childEntity. In the right pane, you see a list of datacenter links.  Click the datacenter link where the vDS is defined.
  7. In the left pane, search for the row with the word networkFolder, and open the link in the right pane. The link is similar to group-n (network).
  8. In the left pane, search for the row with the word childEntity. You see a list of vDS and distributed port group links in the right pane.  Select the dvportgroup that is for the Uplink.  
  9. In the left pane, search for the row with the word config, and click the link in the right pane.
  10. In the left pane, search for the row with the word configVersion. It is normally the first row.  WRITE THIS NUMBER DOWN!
  11. Go back one page and select ReconfigureDVPortgroup_Task
  12. Delete the contents that you see under Value and replace it with the syntax below.  Fill in configVersion with what was captured in Step 10.  The field for numPorts is what you want to increase the number of uplink ports to.

    <spec><configVersion>0</configVersion><numPorts>20</numPorts></spec>

  13. Select Invoke Method
  14. Optionally, if you don’t trust what you just did, scroll up and select the config link and see if your numPorts field increased
  15. You will notice that if you go back into vCenter, the number of Uplink ports will be reflected.  However, don’t get too excited yet.  You’re not out of the woods until you have restarted the vCenter Server.

vds2

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