I recently had a requirement to build a script that listed all PST files on some of our DFS folders. I know there are a bunch of ways to get this done, but I wanted to build my own way. Since we needed to search roughly 20 directories, I decided to play with the Start-Job cmdlet so I could have one script to spawn multiple worker processes. At first, it was tricky (since I had never even messed with it), but anyone can easily pick it up.
SysAlive – VB app for monitoring IP addresses via Ping
Another app I wrote in May of 2006 in VB.Net, apparently my “first” app according to my comments. I’ve written others in VB.net 5.0, 6.0, and 2003 for class, but I guess this was one I actually wrote for a void I needed to fill. I worked in an IT shop dwarfed by the rest of the company. I’m sure several of you have dealt with the politics of upper management viewing IT as a monetary black hole. This was us, wanted us to make everything work, without giving us anything to work with. That’s a whole different rant, though, so I’ll cut to the good parts.
FTPLockDown – VB service fights against dictionary attacks in IIS 6 FTP
I wrote this app some time in January of 2007 in VB.Net 2003 (maybe 2005). I ran an FTP server on Windows 2003 and could see in the logs where I’d have thousands of failed login attempts, which turned out to be dictionary attacks. I got tired of manually blocking the source IPs and started kicking around ideas around stopping them.
Enter FTPLockDown
Script to pull host UUID for VMware PowerCLI
A reader on a previous post asked about pulling host UUIDs, so I wipped together this script.
Usage is like this:
Get-VMHostUUID.ps1 -vmhosts ("host1","host2","host3")or
Get-VMHostUUID.ps1 -vc vcenterserver -container cluster1/folder/dc/etcDRS Host affinity in 3x & 4.0 – keeping a VM from migrating to a different host
Using DRS in vSphere is a great thing for load balancing your cluster, but what if you need to keep one VM from vMotioning to another host? Everyone mention’s host affinity when searching, but digging through the DRS settings doesn’t really show much.
The closest thing to ‘Host Affinity’ is this KB article from VMware.
System Error: vmodl.fault.hostcommunication
I upgraded one of my lab hosts to ESXi 4.1 yesterday and was plagued with this error:
vmodl.fault.hostcommunication
A lot of people are getting this error without a lot of direction. As it turns out, this is because I upgraded one of my hosts to 4.1 without upgrading vCenter to 4.1. Silly me! Who would have thought that vSphere vCenter couldn’t manage a vSphere host because it’s rev is 0.1 higher?
Playing with the Dell Streak – GSM Android ‘Tablet’ Phone
I recently got the chance to play with the Dell Streak. If you haven’t heard, the Streak is the latest GSM Android phone from Dell. I use the term phone loosely, however, as it’s more of a tablet.
Sure, it’s a phone, but using it as a phone felt quit odd, like I went back in time and was holding an old ‘brick’ phone to my head. Ideally, you’d want to use some form of handsfree device with it so you don’t have to hold the tablet up to your face.
VMware vSphere 4.1 Configuration Maximums
ESXi 4.0 Update 1 brought with it one major update (as I pointed out here). Now that 4.1 was released on July 13th, I wanted to take a look and see if anything else major has been changed.
Biggest change was they lifted the 160 VMs per host in an 8-node HA cluster. Now it’s the maximum of 320 VMs per host, and a maximum of 32 nodes per HA cluster. Problem is, they imposed a maximum of 3000 VMs per cluster (standard, HA, or DRS, they no longer differentiate them), so you’d just have to find your sweet spot to maximize how you want your cluster set up. Not that 3000 VMs per cluster is a problem, but if you ran 320 VMs on 75% of a 32-node cluster (leaving 25% for failover), that’s 7680. That’s a difference of 4680 VMs. At any rate, I’m glad they lifted the 40 VMs per host in a 9+ configuration.
The Configuration Maximums for 4.1 can be found here.
Here are some of the key features that have changed:
VMware ESXi 4.1 brings Scripted Installs!!
This is a welcomed (and much demanded) added feature to ESXi. I talked about the deployment of multiple ESXi hosts previously and how I used a golden image to lay down on individual SD cards.
It’s currently supported using a boot CD or PXE. However, the scripted installation is only for local or remote disks, installation on USB devices (SD cards, etc), isn’t currently supported.
It’s very similar to ESX, in that it uses a kickstart file to load the OS, and can be pulled from all the typical locations (FTP, HTTP, NFS, USB, etc).
At least this is a huge step in the right direction.
For more information on the install of ESXi 4.1, see chapter 5 of this doc.
VMware’s Advanced Options for HA Cluster – das.slotCpuInMhz das.slotMemInMB das.SlotNumVCpus
Since deploying the Nexus 1000v, it set our slot sizes in the cluster to 1.5GHz and 2GB of RAM. Not wanting to waste slots in our cluster by guests that may not reach that size (or partially fill slots), I wanted to carve out the cluster into slots of a lesser size, similar to using smaller block sizes on a drive to maximize space.
Using percentage reservations with vSphere, you can get by the slot sizes, but what if you’re starting a small cluster and growing it as resources are needed? How could I carve 25% out of a 2-node cluster? Sure, you can do it, but if you’re operating at the full 75% (with 25% reserved for failover) and lose a host, you actually don’t have enough resources and are over-committed by 25%.
Setting the following settings will help reduce your slot size, but may also have a negative impact by not having enough reservations if you end up in a failover state.
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