Posts Tagged ‘virtualization’

USN Rollback on a Domain Controller

This one bit me in the behind a while back. Essentially, the AD server was restored from a snapshot but had USN numbers that were younger than another servers’ USN numbers which was trying to connect to the AD server. This put the AD server into “disabled” mode so it wasn’t being used for AD stuff. The only way I could permanently fix my USN rollback issue was by keeping the other server off and restoring it to a previous snapshot as well. Long story short, this sucked to fix.


Couple of links:


Diskpart FTW!

So I’m playing around w/ a SAN for home use. We’ve virtualized about 80% of our infrastructure at work but most of our VM hosts are standalone with local storage only. So, I’m spending a lot of time at home recently building a SAN on OpenSUSE 11.3 with high hopes of getting iSCSI to play nice. Part of this equation is getting another box to run vCenter Server which will need access to the iSCSI LUNs the VM hosts see.

Hence the title. Windows has a utility called Diskpart.exe which will allow you to turn off auto mount BEFORE you connect your Windows’ iSCSI initiator to your iSCSI target.

Open up a command prompt and type:


Once you’re in the diskpart tool, type ‘automount’.

DISKPART> automount
Automatic mounting of new volumes enabled.

Then finally, ‘automount disable’.

DISKPART> automount disable
Automatic mounting of new volumes disabled.

This will keep your OS from trying to mount your iSCSI volume and mess with your VMFS partition!

Keep in mind, this means any new volumes your system sees will need to be mounted manually w/in the disk partitioning tool.

While you’re in there, type just a ‘?’ and see the whole list of commands you can play with. See the Microsoft KB article below for a more thorough introduction!

Windows 7 slmgr

I do a lot of virtualization both at home and at work. Several times I’ve needed a way to extend the activation period of Window 7 because I’m not done w/ a project.

Enter Windows Software Licensing Management Tool.

If you open up a command prompt by right clicking it and selecting, “Run as administrator” you can run the slmgr.vbs command such as…

C:\Users\yournamehere>slmgr /rearm

This can buy you some valuable time before you delete that VM and start on something else. This command ‘rearms’ the activation period and I believe you can do it for a total of 3 times before it stops working. Also, try adding a /? on the end to see a handy dialog box w/ the other available options.

Quickie on Dovecot. Suicidal daemon…

This post is out of sequence but I told myself I’d throw it up while it’s still fresh. About a month ago I redid my entire email server from scratch when I started having some hardware issues. This post is on one of those bug-a-boos of switching from a physical server to a virtual world. TIME. Seems keeping vmguests synchronized with the correct time is an issue and wrecks havoc upon Dovecot (even when vmware tools are installed!) So, one of solutions was to not only install the vmware tools on my vmguest but to also install ntpd. This is good and bad…

  See, ntpd checks the time rather frequently and all it takes is a sync of > 75 seconds and Dovecot kills itself. Thankfully, it left a message in the log file.

dovecot: Time just moved backwards by 109 seconds. This might cause a lot of problems, so I’ll just kill myself now. 1 Time(s)

The URL provided in the error message was very illuminating and gave some recommendations from there. I installed the script that used lsof and was pretty much good to go. I did a couple of tests to ensure it wasn’t just restarting it once per minute then did the old crontab -e command and placed the script in the root’s cron jobs file stored at /var/spool/cron/root. Life is good. I’ve always been a big fan of netstat but lsof also gives some very valuable information on tracking down rogue issues.

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