Yellow Bricks

by Duncan Epping

BC-DR

File Level Recovery from within a VMDK backup

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Today there was a cool article released on the Storage Nuts & Bolts blog. It’s about file level recovery from within a VMDK based on an NFS datastore. NFS is just mentioned cause this is the preferred way to go for the NetApp family, but it doesn’t matter NFS or VMFS the solution they came up with works for the both of them.

This option was recently discovered and further developed (Registry entries and Batch script) by one of the NetApp SE’s (Mike Arndt) and it’s very effective and free for those customers that already have a CIFS license with their NetApp arrays, which is a very large percentage. The other important factor is that Mike has made it a point-and-click process. Great job Mike!!!

As part of their VMware Disk Developer’s Kit, VMware provides a vmware-mount.exe utility that allows for mounting an existing VMDK on a Windows Driver letter. We’ll be using this utility as well to mount the VMDK as well as some Registry Entries and a Batch Script to further simplify the file recovery process.

I don’t to republish the complete article, so visit the blog and use the script and registry settings these guys created. Especially the first option with registry settings, which give you the possibility to mount a VMDK with just a “right click – mount” action is great!

VCB and Solaris 32 Bit VM’s

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One of my readers just emailed me the following, again thanks for this info which might me useful to any of you guys out there playing with VCB:

Today with the help of VMware Support I solved a strange problem.
With all my Solaris10-32Bit VM’ s I was getting an error, when I tried to backup them via VCB. Creating snapshot of the VM failed with “Creating a quiesced snapshot failed because the (user-supplied) custom pre-freeze script in the virtual machine exited with a non-zero return code”. But there doesn’t exists a pre or post script in all of the VMs.

So as you know, no snapshot means no backup of this VM. I monitored the hostd of the host, where the VM is running. There I saw this messages: ” Could not run custom freeze/thaw operation: Insufficient permissions in guest operating system”.

VMware support told me, that there is a problem within the VMTools in the Solaris VM’s. They know about this problem (I didn’t find anything about this in the internet) and will solve it in a future patch.

For now, the only way is to use the “-Q 0” switch with the vcbmounter command. This way VCB will ignore any pre or post scripts.

Christoph P.

So in short, -Q 0 disregards any pre or post scripts. Thanks Christoph for contributing to my blog!

Selective VCB fullvm images

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During the VMware course DSA I discovered that it is in fact possible to dump specific vmdk’s with the use of the default VCB tools. While I was finding out a way to script this I was notified in one of my blogs by JTurver(Justin Turver) that he already wrote a script that could do what I was looking for. It’s a great script for dumping all system disks and leaving the disk that are filled with data alone. You can use a text file as input for the vbs script. Check out his blog on the VMware website! Great work and thanks for pointing me out!

VCB: I forgot all about “automount disable” what now?

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Before installing VCB and connecting the proxy host to the SAN you should disable automount via diskpart(cmd, diskpart, automount disable, automount scrub). When you don’t disable automount Windows will signature all “incoming” disks. When this happens the VMware hosts will not recognize the VMFS volumes anymore. But fortunately you can re-label the luns as VMFS.

Check with “fdisk -lu” what the current ID value is of the volumes, it’s “SFS” if Windows wrecked it. Write all the devices down and label them again as VMFS:
fdisk /dev/sd? (? the letter for that specific volume)

p
d
n
p
1
default
t
fb
X
b
1
128 (disk alignment, check your SAN manual for the correct value, 128 is correct in most cases…)
W

Now rescan the HBA devices, esxcfg-rescan vmhba0 etc etc.

Undocumented VCB config.js feature

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One of my customers wanted to use the default VCB framework but did not want to quiesce the VM for several reasons. (Databases, Active Directory etc.) I could not find an option in the config.js file but noticed the following in the file glue.js:

// A fallback to be able to switch to non-quiesced snapshots
if (typeof(NO_QUIESCE) != "undefined") {
cmd +="-Q 0 ";
}

In other words, setting the option “NO_QUIESCE” with no value in config.js results in the VM not being quiesced, default it will quiesce the VM! I added the following line to the  config.js file to accomplish this:

NO_QUIESCE="";