Fluke 17B+ multimeter review

This is just a quick and honest review of my Fluke 17B+ multimeter.

Pros:

• Excellent build quality and decent/safe input protection.
• Nice large screen with good backlight.
• Continuity tester seems fairly fast and the latching works well.
• Has a diode tester, frequency, thermistor input and can measure in the microamp range.

Cons:

• Hold function is not Fluke's auto hold (as you would get on the 87V), it simply freezes the current display.
• Only 4000 count with 0.5% +3 accuracy (DC volts).
• Not a true RMS meter.

The included TL75 test leads seem sufficient and seem to be of a reasonable quality.

As a hobbyist, this multimeter should serve me well. If you need more precision or you do AC measurements you might want to consider something like the Brymen BM257S.

I had assumed the 17B+ would have featured auto hold, so I was a bit disappointed about that (in fact it probably would have swayed me toward the BM257S) but I'm certainly not disappointed in the overall product.

A potential backup solution for small sites running VMware ESXi

Today, external consumer USB3 and/or eSATA drives can be a great low cost alternative to tape. For most small outfits, they fulfil the speed and capacity requirements for nightly backups. I use the same rotation scheme with these drives as I did tape with great success.

Unfortunately these drives can't easily be utilised by those running virtualised servers on top of ESXi. VMware offers SCSI pass-through as a supported option, however the tape drives and media are quite expensive by comparison.

VMware offered a glimpse of hope with their USB pass-through introduced in ESXi 4.1, but it proved to have extremely poor throughput (~7MB/sec) so can realistically only shift a couple of hundred GB at most per night.

I have trialled some USB over IP devices; the best of these can lift the throughput from ~7MB/sec to ~25MB/sec, but the drivers can be problematic and are often only available for Windows platforms.

This got me thinking about presenting a USB3 controller via ESXi's VMDirectPath I/O feature.

VMDirectPath I/O requires a CPU and motherboard capable of Intel Virtualization Technology for Directed I/O (VT-d) or AMD IP Virtualization Technology (IOMMU). It also requires that your target VM is at a hardware level of 7 or greater. A full list of requirements can be found at http://kb.vmware.com/kb/1010789.

I tested pass-through on a card with the NEC/Renesas uPD720200A chipset (Lindy part # 51122) running firmware 4015. The test VM runs Windows Server 2003R2 with the Renesas 2.1.28.1 driver. I had to configure the VM with pciPassthru0.msiEnabled = "FALSE" as per http://www.vmware.com/pdf/vsp_4_vmdirectpath_host.pdf or the device would show up with a yellow bang in Device Manager and would not function.

The final result - over 80MB/sec throughput (both read and write) from a Seagate 2.5" USB3 drive!

BlackBerry MDS proxy pain

I'm just having a rant about MDS SSL connections through a proxy. Non-SSL traffic will work fine, however SSL traffic appears to go direct even when proxy settings have been defined as per KB11028. My regular expression matches the addresses fine.

Surely people out there want/need to proxy all their BES MDS traffic?

DNS resolution on iPhone

I've been playing with a few iPhones lately and have had trouble getting WiFi working through our proxy. After much hair pulling the problem turns out to be a feature in the iPhone DNS resolver that refuses to look up any hostname ending in ".local". This also appears to be a problem on Mac OS X:

http://support.apple.com/kb/HT2385?viewlocale=en_US

With OS X you can add "local" to the Search Domains field and disable this behaviour, unfortunately it doesn't work for the iPhone.

Data destruction

After cleaning my home office I was left with some old hard drives to dispose of, this got me thinking about data destruction. In the past I cleared my drives with a couple of passes of random data using dd, but is this thorough enough?

This time round I have used a free bootable CD called CopyWipe (great utility, BootIt NG is also worth a mention). Each drive was given 5 passes, and then taken to with a hammer just to be sure. I've linked a picture to the "after" shot.

I can see data destruction being a larger problem as time goes on. I'd be interested to know the techniques others use for this problem.

Archiving files from my Topfield PVR

I've had a Topfield PVR for quite a few years now. The unit is great, I can't fault it really. Until recently I did however have one ongoing problem; I kept running out of space! To help combat the space problem I upgraded to a Samsung 400GB drive but this was only a short term band-aid.

The next solution was commissioning a Linksys NSLU2 running uNSLUng and ftpd-topfield to allow FTP access to the unit (my computer isn't anywhere near the TV and the Topfield only has a USB port). So the space problem on the Topfield was fixed, but I had loads of transport stream files sitting on my computer. It was just too expensive (time-wise) to edit out all the ads, convert to MPEG-2 and burn to DVD or DivX. So last weekend I scripted it:

• Create ad removal cutpoints with comskip
• Feed the cutpoints into ProjectX then demux
• Combine the audio and video into an MPEG-2 file with mplex
• Encode with Dr. DivX OSS

Seems to work quite nicely, the ad detection works fairly well but it's not 100% perfect. One thing I had to do to get comskip working was rename the file extension from REC to TS.

The whole thing was fairly trivial after reading the CLI documentation for each program, but if you need a hand feel free to contact me.

Moving from VMware Server to ESXi

At home I'm currently using VMware Server with Windows 2003 as the host OS. In addition to running 5 guest operating systems, the host OS performs the following tasks:

• Shuts down the server in the event of an extended power outage thanks to APC PowerChute.
• Backs up the VMDK files to locally attached USB hard drives.
• Allows remote administration via Terminal Services (Remote Desktop).
• Hosts my complex virtual networking services including NAT (with port forwards) and routing for the virtual machines.

Lately I've been reading up on VMware ESXi and it appears as though my existing hardware is going to work, however I'm having a hard time deciding if the extra efficiency is worth the hassle. From what I've read I will have to find a different way to perform backups since local USB devices aren't supported, in addition I will have to provision a VM to perform the NAT and routing duties. On the other hand the I/O struggles at times with VMware Server so the extra performance and stability from ESXi would be welcomed; I've had VMware Server's NAT implementation crash twice during 18 months of use.

If anyone out there has made the move, I'd love to hear their experiences and feedback!