Greets,

Okay, yes the eSATA drive is VMFS3, and the VMDK in question is on the VMFS.

The VMDK that I have lost "contact" with was simply a virtual drive. One of my servers running on the ESX was accessing this additional eSATA drive as a data storage drive for daily differential backups. Nothing major size-wise.  The physical hard drive is 1TB, but formatted it comes to 931.25GB. 

Of this, I made an 800GB virtual drive. Specs are VMFS 3.31 and Block size: 4MB.  This leaves 130.68GB free. (14%?).

I was able to make another virtual drive while troubleshooting of 120GB, and was able to mount it etc. I have since deleted that drive to return the free space. To me this means the physical equipment is fine, its just a problem with the VMDK.

When I try to power on the backup VM with the virtual drive attached, I get the error:

Cannot open the disk '/vmfs/volumes/4a0c9734-c2a1d850-ce-000f1f6d886a/2003 Server/2003Server_1.vmdk' or one of the snapshot disks it depends on.  Reason: Invalid argument.

If I click OK and disconnect that virtual drive, the VM server boots up fine.

Your command requests show this:

Re: Virtual drive on eSATA drive won't mount.# esxcfg-vmhbadevs -q

vmhba2:0:0 /dev/sdb

vmhba2:1:0 /dev/sdc

vmhba32:0:0 /dev/sda

Re: Virtual drive on eSATA drive won't mount.# fdisk -l

Disk /dev/sda: 1000.2 GB, 1000204886016 bytes

255 heads, 63 sectors/track, 121601 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot    Start       End    Blocks   Id  System

/dev/sda1             1    121601 976759968+  fb  Unknown

Disk /dev/sdb: 36.4 GB, 36419010560 bytes

64 heads, 32 sectors/track, 34731 cylinders

Units = cylinders of 2048 * 512 = 1048576 bytes

   Device Boot    Start       End    Blocks   Id  System

/dev/sdb1   *         1       100    102384   83  Linux

/dev/sdb2           101      5087   5106688   83  Linux

/dev/sdb3          5101     32087  27634688   fb  Unknown

/dev/sdb4         32088     34731   2707456    f  Win95 Ext'd (LBA)

/dev/sdb5         34632     34731    102384   fc  Unknown

/dev/sdb6         32088     32631    557024   82  Linux swap

/dev/sdb7         32632     34030   1432560   83  Linux

Partition table entries are not in disk order

Disk /dev/sdc: 146.8 GB, 146814664704 bytes

255 heads, 63 sectors/track, 17849 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot    Start       End    Blocks   Id  System

/dev/sdc1   *         1     17849 143372028+  fb  Unknown

The system has a 36GB SCSI Mirror, a 146GB SCSI Mirror and the eSATA  1TB

Thanks for your help.

Yes that's the thing. The eSATA card is there, and I see the virtual drive under storage. But if I right click it and try to say add to inventory, that option is grayed out.

I can't "add" the drive to my VM while its turned off. ESX says that it completes the add and I can click OK. When I try to pow on the VM, I get the message at the top of the page about "invalid argument" and the VM shuts off. As soon as disconnect the virtual drive and power on the VM with only its main drive, it starts right up.

I haven't had to refresh anything, although I have noticed that now the drive is showing a size of 838GB instead of just 800.  I don't recall seeing it that size but it could just be a fluke. It has not been powered on long enough to add anything I think.  

In the end I could just delete that drive and reset it up. I would have to recreate backup to disk folders again and lose the backups I made, but they are only from last week so no large harm there. I would just hate to do that and then find out an hour later there was an easy but not so noticable fix for the problem.

I finally reached that point of spending too much time trying to fix the issue. Since I only had 1 week worth of backup data and nothing has happened since then, I just deleted the drive completely, reset it up and reconnected it to Backup Exec 12.5. It seems to be working great for now.

Thanks for all that contributed!