guy labs guy labs

VMware Snapshot and recovery: fix active directory replication

Windows
/by
Two weeks ago I tried to install the newest updates onto one of our virtual domain controllers. Shortly explained it was not the best idea and I had to recover to the snapshot taken just before I launched the update process, lucky enough I remembered to take one. :) Yesterday morning I was told that the active directory content was different on both domain controllers. I found that hard to believe and had to take a look myself and yes, the content was different. How did that happen? I knew recovering from a snapshot may result in issues but I didn't see it in the first place. After looking around I found out I had a so called USN rollback to do because of a "dirty" rollback of the active directory. Microsoft is aware of the issue and has posted an article about it: http://support.microsoft.com/default.aspx?scid=kb;EN-US;875495 So the way would have been demoting and promoting a domain controller, and this during the day? No way... there had to be another solution. So I checked the replication status: Result was: This was odd, I checked the USN on both machines and they were identical. So the replication was not a total failure, but somehow not working as usual. Next I wanted to make sure the inbound and outbound replication were working and that the global catalog was still working: And there it was, the output revealed the problem: Inbound and outbound replication were disabled on the recovered virtual domain controller. So enabling those two parameters did the trick: After waiting...

Introducing DHCP Failover in Windows Server 2012

Windows
/by
One of the most central feature there is within a private network, not depending on size or architecture, is DHCP. Until today Windows server was not able to have a failover feature implemented, only exception was to include the feature in a Windows failover cluster. But not anymore: it became a feature in Windows server 2012. Of course it only runs on Windows server 2012 so you will have to upgrade your two servers first which will hold the two DHCP roles. After you successfully upgraded: 1. Install the DHCP role on the server1 and set up the first DHCP server according to your needs. Authorize the server and create your DHCP scopes. 2. Switch onto the server2 and install the DHCP role as well. Authorize the server. 3. Switch back onto server1 and right-click “configure failover” (IMAGE) 4. When asked for partner server enter the FQDN of server2 and click “Next” 5. Give the relationship a name, enter a shared secret for the relationship to use and click “Next” 6. Leave settings for MCLT*, change operation mode to “hot standby” and finish wizard Voilà, that’s all there is to do. You’re set up for DHCP failover, do not forget to present the IP address of the second DHCP server to all your other components. For more detailed information and all powershell commands to realize this cool new feature on server core visit the following link from the Microsoft Technet: http://blogs.technet.com/b/teamdhcp/archive/2012/06/28/ensuring-high-availability-of-dhcp-using-windows-server-2012-dhcp-failover.aspx   Picture: http://technet.microsoft.com   *Definition of MCLT (Technet): The Maximum Client Lead Time (MCLT) is additional time provided to a DHCP client...

My server

Personal
/by
Hi folks, in my posts I always talk about my server and now I want to reveal the secret and show you my little home server and it's configuration. When we renovated the flat we added a selfmade homecontrol system which controls light and sound in each room. For that I wrote a small Java application which controls everything. And this application needs to run on a small server attached to a touchscreen to turn the light etc. on and off. So the server needed to be small, silent and powerful enough to host some developer applications etc. So here is the configuration of my server: Intel Core i7 3770K BOX, 3.5GHz, LGA 1155, 4C/8T, unlocked Asus P8Z77-M PRO, Z77, LGA1155, PCI-E 3.0, SLI/CFX, mATX 3x Western Digital Red, 64MB, 1TB, SATA-3, 24/7 NAS Corsair Vengeance LP, 4x8GB, DDR3-1600, CL10@1.5V be quiet! Pure Power L7-430W, 80 plus Bronze Xigmatek Gigas mATX-Cube - Black Zotac GT-610 Zone Edition 1GB DDR3, PCI-E x16 2.0 Noctua NH-U12P SE2, Sockel 1366/1155/AM3 It looks like a big server but the case (the Xigmatek Gigas mATX-Cube) is just 278x322x396 mm (WxHxD). I also wanted to have enough memory and a RAID 1 configuration for the hard disks in case a hard disk failure occurs. The rest is just standard except the CPU cooler which is a huge and extremely silent Noctua cooler. I can just recommend you such a nice CPU cooler. Right now when we have a room temperature of arround 30° degrees celsius the CPU has something arround 52° degrees celsius. So a quite good result for such...