Heads up: The upcoming Leap Second adjustment may affect your IT infrastructure!

Okay, probably everyone is aware of the upcoming leap second time adjustment on June 30th, 0:00 UTC. I won't explain the story behind it although it's a very interesting topic, but others have done this already. A good starting point is the Wikipedia Leap Second article.

You might wonder: Okay, this is an anomaly that is confusing, but it's only one second, and modern IT systems should not really stumble over this, right? I was of the same opinion until recently, but the nearer the time comes the more IT vendors alert their customers of leap second related issues in their products, and you might be surprised to hear that very critical parts of your infrastructure can fail on June 30th if you do not patch them before!

Filtering logs in ESXi 6.0 - A practical example

Recently I rented a new server with an LSI MegaRAID SAS 9260-4i controller and - of course - installed VMware ESXi 6.0 on it. I will soon migrate my "production workloads" (the V-Front Online Depot, the ESXi Patch Tracker site and my Zimbra E-Mail server) onto this box to improve their availability. A disk failure is one of the most likely disaster scenarios, so a hardware RAID controller with two mirrored disks will certainly help.

After I had the host installed and configured I did a routine check of the log files and found a lot of SCSI errors like these in /var/log/vmkernel.log:
cpu1:34460)NMP: nmp_ThrottleLogForDevice:3178: Cmd 0x1a (0x439d80668b00, 0) to dev "naa.600605b0058b25f01c995a4f0b03da18" on path "vmhba1:C2:T0:L0" Failed: H:0x0 D:0x2 P:0x0 Valid sense data: 0x5 0x24 0x0. Act:NONE
cpu1:32779)ScsiDeviceIO: 2646: Cmd(0x439d80716d00) 0x4d, CmdSN 0x1 from world 34425 to dev "naa.600605b0058b25f01c995a4f0b03da18" failed H:0x0 D:0x2 P:0x0 Valid sense data: 0x5 0x20 0x0.
These errors were referring to the RAID 1 disk, and first I was worried about them - according to KB289902 the D:0x2 translates to "Device: Check condition" and the sense data codes 0x5 0x24 0x0 and 0x5 0x20 0x0 mean "Illegal request", "Invalid Field in CDB", resp. "Invalid command operation code". I double checked that the RAID controller is on the VMware HCL, I searched the Internet for these errors, found few peoples' posts describing this issue, but no solution. I even updated the firmware of the controller, all to no avail ... and then, finally, I stumbled over KB1031221 which - basically - describes that these errors are "normal" and "can be safely ignored".

Well, that calmed me down... But I'm a log purist: I wanted to get rid of these false error messages in vmkernel.log!

What's new in the V-Front Online Depot - or - how to install ESXi on an HP Pavilion 17 notebook

Recently I added some new NIC drivers to the V-Front Online Depot. Well, they are not really new, but were created back in 2011/12 by a Japanese guy who goes by the nickname ichi. He was actively participating in Dave Mishchenko's vm-help.com forums and posted the drivers there.

Although I was aware of them since then I did not add them to the Depot before - I thought that no one would really need them these days, because the NIC models that they support are pretty old and rarely used today. I was wrong, at least in one case, because I needed one of these drivers myself to install ESXi on a brand new HP Pavilion 17 notebook that I just purchased ...

CPU Microcode Updates revisited: What's new in ESXi 6.0?

Almost two years ago I wrote an FAQ post on CPU Microcode updates with ESXi 5.x. This still gets a lot of hits, but - although the general information about Microcodes still applies - the ESXi related information needs an update, because things have changed with ESXi 6.0.

So what's new and different now?

[Release] ESXi-Customizer-PS 2.4 - The ESXi image customization script

I have just released version 2.4 of my ESXi-Customizer-PS script - a PowerCLI script to create customized ESXi installation images and the successor of my legacy ESXi-Customizer tool.

This is a minor, but important update, because it fixes an annoyance that users of the latest PowerCLI version 6.0 ran into.