SAS adapter visible, but LTO5 tape drive not

[ScotofMKE]

I've got a Dell 6GBps SAS HBA adapter and Dell LTO5-140 tape drive setup on the ESXi 4.1 host.  Both devices are on the HCL.  The adapter is configured for VMDirectPath.  The tape drive, however, is not visible.  Any idea how to get this working? 

[DSTAVERT]

I would do a search in the forums. There are many such posts and different solutions. One result. http://communities.vmware.com/message/1543924#1543924

[ScotofMKE]

I'll take another look.  Most of what I saw had to do with device incompatibility and invisible SCSI adapters. 

[DSTAVERT]

The idea behind VMDirectPath is that access to the hardware is passed directly to the guest basically bypassing ESXi. Make sure you have any software, drivers etc installed in the guest OS. Not every device will be supported under VMdirectpath . Here is a troubleshooting guide. http://www.vmware.com/resources/techresources/10170

[ScotofMKE]

I'll look at that.  I figured a SCSI adapter and attached tape device would have best performance going through VMDirectPath, but could change it if that is the source of the problem. 

[DSTAVERT]

The only official VMware tape support is Adaptec Parallel SCSI (not SAS) in passthrough. It has been done with SAS in passthrough and some manufacturers directly support passthrough for SAS. I would check with Dell support to see what their support policy is for SAS attached tape devices.

[ScotofMKE]

I removed the adapter from VMDirectPath, reboot the host, then attempted to add the SCSI device (tape drive) in the vm properties.  The tape device was recognized this time, and I added it.  It appeared in Windows when I restarted the VM.  Beautiful.  Thanks for pointing me to the VMDirectPath.  I'll see how well the backup works going through the hypervisor layer.

[DSTAVERT]

Great and good luck. It will be helpful for others if you document the steps you took and the success of your backups etc.

[ScotofMKE]

I thought this issue was complete after I removed the SAS adapter from VMDirectPath, and my tape drive was subsequently recognized by ESXi.  Backup Exec produces errors, however, such as "device may no longer be accessible" and other atypical behavior when attempting a backup.  Dell tells me the SAS adapter should work, but some searching on the VMWare forums tells me only some Adaptec adapters are supported.  If the answer is that the SAS adapter is not officially supported, I'll return it.  If it should work, I'll take more suggestions for getting this thing going.

[DSTAVERT]

You can have a look at this KB article. http://kb.vmware.com/kb/1031497 You may be able to use it as a guide. While it is specifically about another manufacturers device most of the tape devices and SAS cards are the same.

[ScotofMKE]

That article was helpful for something new to try, but same problem.  When the SAS adapter was configured for VMDirectPath, the tape drive was not seen by Windows.  The name of the SAS adapter (and as recognized by the host) is "LSI Logic/Symbios Logic Dell 6Gbps SAS HBA".  In Windows, it sees it as "LSI Adapter, SAS 3000 Series, 8-port with 1068".  I attempted to install the Dell driver, but received a notice of "This update package is not compatible with your system configuration". 

I suspect the adapter & tape combo just isn't going to work despite what the Dell sales person confirmed.

[ScotofMKE]

My Dell tech person let me know the SAS controller isn't supported by VMDirectPath.  The adapter IS on the VMWare compatibility list.  How is the compatibility list supposed to be interpreted?  Does it mean the product is compatible "sometimes"?  All I'm looking for is a SAS adapter that will work with an LTO 5 tape drive and ESXi 4.1.  All I need is a backup to work.  I hope an answer posted here will save someone else hours of their own searching. 

[DaveFixedIt]

I don't know if this will be of use to anyone, but I have just been working on what sounds like a similar configuration with Dell kit: A single PV110T LT0 4 tape drive from Dell with the LSI Logic/Symbios Logic Dell 6Gbps SAS HBA adapter, Windows 2008 R2 and Backup Exec 2010 R3 on a PowerEdge T610 and MD1000 arrangement. We are running ESX 4.1 Essentials update 1.

Initially I configured this to be a shared device (the default that happens automatically on adding it to the machine) which I added to the virtual server in ESX. It was then visible in Windows 2008 R2 and Backup Exec could also find it. However, when trying to backup it failed saying that the drive was not accessible (occurred after a minute or so when attempting to write to the drive).

Having read through various posts I assumed that it would only be possible to get it to work with an Adaptec card (if at all given warnings about SAS support). However, before doing some shopping I gave it a go as a Passthrough device as it was not a tape library. This is detailed quite nicely on http://www.servethehome.com/configure-passthrough-vmdirectpath-vmware-esxi-raid-hba-usb-drive/

In summary:

1. Remove the SCSI drive from your virtual server.
2. Setup the HBA card as a Passthrough device for ESXi
3. Reboot ESXi
4. Add the card as a PCI device to your virtual server
5. Boot the virtual server
6. Run up Backup Exec and install the device drivers (I think that I chose to use the Symantec ones).

This will only allow one virtual server to see the drive, but also should give better performance than using it as a virtual device and suits our need fine.

To be fair I have only run one backup/verify of about 20G with this configuration thus far, but it ran the backup at 2G/min and the verify at 7G/min and didn't report any errors with the drive.