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ESX/vSphere EtherDrive HBA FAQ

Q 1: When I attempt to create a datastore on one of my SR[X]'s LUNs, the operation takes an inordinate amount of time to complete, does not complete at all, or I receive the error: "Unable to create Filesystem." Is there something I should check?
Q 2: After installing the EtherDrive HBA and driver my ESX server sees my SR LUNs as 2 TB, even though the LUNs I created on the SR are larger. Is something wrong?
Q 3: On ESXi 4.1 and 5.x, when I try to create a datastore on one of my SR LUNs, I receive an error: "Call HostDatastoreSystem.QueryVmfsDatastoreCreateOptions" for object "ha-datastoresystem" on ESXi "example.coraid.com" failed.
Q 4: An AoE LUN has gone offline and now my ESX box hangs. Is this normal?
Q 5: Is RDM available for EtherDrive storage?
Q 6: I still need help. What should I do next?

Q 1: When I attempt to create a datastore on one of my SR[X]'s LUNs, the operation takes an inordinate amount of time to complete, does not complete at all, or I receive the error: "Unable to create Filesystem." Is there something I should check?

This is a common symptom when support for 9000 MTU is lacking between the ESX host and the SR[X], generally because a switch in the path is not configured for jumbo frames or simply does not support jumbos at all. The EtherDrive HBA requires adequate support for 9000 MTU, so a good first step would be to check your switch's configuration and/or capability. A good test to rule this variable out is to try the same operation with the EtherDrive HBA connected directly to the SR[X], bypassing the switch; if the operation works fine with the direct connection, there is likely a problem with the switch or its configuration.
Q 2: After installing the EtherDrive HBA and driver my ESX server sees my SR LUNs as 2 TB, even though the LUNs I created on the SR are larger. Is something wrong?

Due to VMware's implementation of the SCSI-2 industry standard the largest extent size that ESX and ESXi can use is 2 TB; for this reason the EtherDrive HBA automatically presents a LUN greater than 2TB as multiple LUNs segmented at 2TB boundaries. For example, a 5TB LUN is presented to the ESX server as two 2TB LUNs and one 1TB LUN. The segmented LUNs can be put back together by Virtual Infrastructure by using the "Extend Datastore" feature.
For further information regarding this 2 TB size limitation see VMware's knowledge base.
Q 3: On ESXi 4.1 and 5.x, when I try to create a datastore on one of my SR LUNs, I receive an error: "Call HostDatastoreSystem.QueryVmfsDatastoreCreateOptions" for object "ha-datastoresystem" on ESXi "example.coraid.com" failed.

This error can occur when there is prexisting partition information at the beginning of a LUN. For this example, we'll show you how to fix LUN 53.5. First we need to find the SCSI device associated with the LUN (output below is snipped for brevity):
On ESX/ESXi w/ HBA release 5.0.3 and later:
```
> ~ # cat /proc/ethdrv/devices    
> vmhba1:C0:T0:L0 53.5 753.178GB
```
On ESX w/ HBA release 2.2 and earlier:
```
> ~ # cat /proc/ethdrv.devices
> 'ESX Device' 'AoE Target' Size
> vmhba1:C0:T0:L0 53.5 753.178GB
```
On ESXi w/ HBA release 2.2 and earlier:
```
> ~ # cat /proc/scsi/ethdrv/ethdrv.devices 
> 'ESX Device' 'AoE Target' Size
> vmhba1:C0:T0:L0 53.5 753.178GB
```
This tells you that LUN 53.5 corresponds to device "vmhba1:C0:T0:L0". Next you run 'esxcfg-mpath -l' to find the block device:
```
 > ~ # esxcfg-mpath -l
 > gsan.10-gsan.03505-naa.2000001004011cf2
 >    Runtime Name: vmhba1:C0:T0:L0
 >    Device: naa.2000001004011cf2
 >    Device Display Name: Local CORAID Disk (naa.2000001004011cf2)
 >    Adapter: vmhba1 Channel: 0 Target: 0 LUN: 0
 >    Adapter Identifier: gsan.10
 >    Target Identifier: gsan.03505
 >    Plugin: NMP
 >    State: active
 >    Transport: parallel
 >
```
... which is "naa.2000001004011cf2". You can then use 'dd' to zero out the partition info at the start of the LUN:
```
 > ~ # dd if=/dev/zero of=/vmfs/devices/disks/naa.2000001004011cf2 conv=notrunc bs=1024 count=256
 > 256+0 records in
 > 256+0 records out
```
After rescanning the adapter you should now be able to use the LUN.
Q 4: An AoE LUN has gone offline and now my ESX box hangs. How do I resolve this?

The latest driver for ESXi 4.1 and 5.0 include a flushing mechanism which allows the user to mark these AoE targets as unavailable to the host.

On ESX/ESXi 4.1, run the following:
echo flush > /proc/ethdrv/ctl

On ESXi 5.x, run the following:
esxcli ethdrv flush
Q 5: Is RDM available for EtherDrive storage?
In ESX 4.0 the RDM system was changed to only permit RDM on non-local storage. Currently only iSCSI, Fibre Channel, and SAS storage types are considered non-local. VMWare has implemented a generic SAN type that we are utilizing, but VMWare has not finished implementing the details necessary to consider the generic SAN type non-local. There is a workaround to enable RDM for local storage types, but it comes with the following caveats from VMWare:
1. RDM is a mechanism that VMware provides in order to support MSCS, as described in our public manuals. Other uses of RDM are not tested. Using RDM to map any other volume that contains sensitive customer data (i.e., outside ESX Server's root file-system, and not MSCS, but still important to the customer) is strictly at the customer's own risk. If the customer loses data in a non-MSCS configuration (i.e., something that we've never tested), we will reject any service or support request.
2. The workaround makes it potentially possible to RDM a volume that holds your ESX Server's root file-system. This is absolutely NOT supported or recommended by VMware. If a customer tries this, accidentally destroys his system as a result, then files a Field Service request or Support Request with us, we will reject the request out of hand.
If you understand these caveats and would still like to enable RDM on ESX4, please contact support@coraid.com for more information.
Q 6: I still need help. What should I do next?

We have hints that will help you get the fastest and best support we can provide at our Fast Support HOWTO. If you still need assistance with your CORAID EtherDrive HBA please send the information requested at the Fast Support HOWTO to support@coraid.com.