stressfree - network

HP LaserJet 2840 recommendation from Mike

David — Sat, 05 Jul 2008 06:36:15 +0000

If anyone is in the market for a multifunction device with a colour laser printing, scanning and fax capabilities, Mike Clements has a good recommendation, the HP LaserJet 2840. This printer is not for the average home user, but if you run a small/medium sized office this printer delivers functionality and features at a very competitive price.

What follows is Mike's thoughts on the device...

I purchased the HP 2840 from Ingram Micro as they offer very competitive pricing within New Zealand. Installation could have been easier, the documentation is a bit average for anything past how to un-pack it and install the software, but once setup is complete it is a fantastic printer. One lesson, remember to leave the SNMP on its default settings (R/W).

This is the only "All in One" device I have ever liked, mainly because of its quality and deep featureset. Here is an overview of what it does:

Prints photos
Photocopies
Scans (flat bed)
Fax machine (inbound and outbound)
Has a 50 page document feeder for scanning, copying and faxing
Built in card reader (SD, CF, XD, MS etc.) that is exposed as a CIFS share on the network (iPhoto even sees it)
Internal JetDirect for network connection & USB 2
Supports network (IP) based faxing and scanning in colour

Here is a list of things that put it above many competing multi-function devices out there:

It is very easy to use.
Full control from either a network PC or at the printer (i.e. pick a machine to send your scanned image too).
The LCD panel is actually helpful with steps and errors.
All the cables you need are provided in the box.
Standard consumables supplied with it are a imaging drum (8,000 pages), Black toner (5,000 pages), 3 x colour (4,000 pages each).
Consumable use is well measured and reported via web admin page.
Errors are tracked and logged (you can email them, send notifications via SNMP to PCs etc).
Faxes can forward, stored on your PC or set to auto-print.
Configuration is all web based via an easy to use administration interface. The settings can then be backed up to a file for easy restoration.
Supports duplex printing via some manual intervention (but not too bad).
Print standards support RAW (port 9100) and LPR printing. This makes it easy to setup via CUPS, NDPS, etc. SNMP is used to detect other devices on the network.
"Straight through" printing is possible to avoid the bending of photos or transparencies.
It has two paper trays; one for photo paper/envenlopes, letter head, etc. and another for your main paper, e.g. A4.
Power saving appears to be excellent with no annoying fans.
Full software and driver support for Windows & Mac (all features) and a reasonable amount of Linux support (but unsure if this is for all features or just printing).
The software suite appears solid, intuitive and unintrusive. This is quite unlike many other HP printer software packages.
TWAIN is supported so graphic applications on your PC or Mac that support TWAIN can scan images from the device direct to the application.
Installation of the PCL and Postscript printer drivers are separate from the full software package, this makes setting up iPrint/NDPS much easier.
Full support for Zeroconf (i.e. Bonjour). As a result it is automatically detected by Zeroconf/Bonjour enabled systems (e.g. OSX, Windows with Bonjour, etc.).

It is not all roses however, there are some downsides:

The device is noisy when printing because it rotates toner cartridges. Whilst not painful, it is louder than your average laser printer.
Tray 2 (main paper tray) only supports 275 pages. This is not to bad but it would be nice to support a full ream of paper (i.e. 500 pages).
The device itself is quite large and will probably not win any beauty contests.

The HP 2840 even does funky things like if you put in a memory card and tell it to print a proof sheet (thumbnails of your photos), you can then mark on the proof sheet which photos to print at what size, and have these photos automatically printed by feeding the proof sheet back into the device.

Honestly this device has really impressed me. It is the printer equivalent to my iPhone/iMac fetish and would be the device I would expect if Apple decided to make one.

TelstraClear problems solved

David — Fri, 09 Jun 2006 11:59:03 +0000

After yet more outages and phone calls to helpdesks I finally have my Internet issues sorted out. The helpdesk guy was pretty stumped on what was causing my outages but I managed to convince him that it was due to another computer on their network somewhere competing for my static IP address. Once he had come around to the idea (and talked to his supervisor) I soon had a fresh static IP and a working Internet connection. Throughout this time I was quite thankful I had recently moved my email hosting onto Google's hosted services. It meant that even though Internet was down for most of the day no mail was lost but it did result in no StressFree website for a while :-(

Weird TelstraClear Internet outages

David — Fri, 09 Jun 2006 03:55:11 +0000

I've been having weird Internet outages today. The Internet will suddenly just drop off for twenty minutes and then mysteriously come back. I called in the morning to report the fault but they had a 40 minute wait for service (probably because others were experiencing similar issues) so I gave up. However after the fourth such outage this afternoon I rang TelstraClear and this time someone answered straight away.

I told them that my Internet was down and that it was not an issue with my internal network because I had checked it all. The guy replied that it was probably spyware and that I should get my computer seen to. His hopes were dashed when I told him it was not spyware because a) it is effecting all my computers, b) none of my desktop computers run Windows and c) the device that 'talks' to the Internet on my network's behalf is a NetScreen and even this can't communicate with the outside world.

He said that it was not their problem because the online light was happily lit on my TelstraClear supplied modem and to his knowledge there had not been any Internet outages today (leaving me to guess lots of people like ringing Paradise in the morning just to catch up on Coronation Street). So I hung up and plugged my OSX laptop directly into the modem to triple check it was not a problem with my Netscreen (or the network cable running to it). I configured it with the Internet details provided by TelstraClear but on pressing Apply was told that it could not connect to the network using the supplied static IP because it was already in use by another device. Just to be extra helpful it told me the MAC address of the device already using my address. I checked my internal network and was unsurprised to find this MAC address did not match any device I owned.

So I rang TelstraClear again, this time armed with the rogue MAC address and all the MAC numbers of my devices (just in case they questioned whether I knew what I was talking about). Again my call was answered straight away which was very good. I explained the situation again and provided the helpdesk guy with the MAC address and he started going through their logs. There was a long period of silence so I tried once again to connect the laptop to their network. This time I was allowed on the network with my static IP but routing seemed to be screwed up. A reset of the modem fixed this and I was back on the Internet.

The helpdesk guy said he couldn't find any trace of this MAC address in their logs (but he did come across a number of incorrect logins to my account which was weird). It was very strange however that my outage corrected itself very soon after I contacted them with specific proof of the problem. I guess I'll have to wait and see how things progress this afternoon as to whether the issue has finally gone away. I only wish when calling their helpdesk it was not so difficult to point out that the issue was not at my end and something was fishy about their network....

Gigabit vs Fibre Channel Discussion

David — Mon, 10 Oct 2005 09:39:46 +0000

My friend Mike has spent a lot of time working on large networks and SAN devices within corporations and government organisations here in Wellington and around New Zealand so when I get curly network questions I usually turn to him. The other day I emailed a really quick question, what provides the most cost-effective high bandwidth network, fibre channel or gigabit?. He soon replied gigabit and then tacked on the end hold on a minute, just writing some notes...

His notes turned out to be a two page series of observations and findings that were so interesting that I asked him if I could put this up on my website so that I could refer others to it. I have edited pieces for clarity and added a bit of background but more or less I have copied things verbatim from his emailed reply....

To start with some people claim that SATA does 1.5 Gb/sec but this is not true as the actual disk throughput is really more like 1.2 Gb/sec. This of course is shared for all calls i.e. operating system, etc, so actual data throughput is more likely 80% of this, at best, 0.96 Gb/sec or 120 MB/sec

A decent gigabit ethernet network does 1 Gb/sec (obviously) however there is a switch limit here and even a decent switch will not be able to switch all ports at 1 Gb/sec at the same time. For example a 48 port ethernet switch is usually broken into 8 lots of 6 ports and each set of 6 shares a throughput of 1Gb/sec concurrently. A good Cisco switch will cost about $160 per port, whilst a good Juniper switch would cost less and probably perform better during high volume data transfer.

Both Ethernet and Fibre Channel (FC) allow multiple ports to be used however this is much more expensive when using FC compared to Ethernet. When multiple ports are tied together they can be used to provide fail-over or load sharing (i.e. making two 2Gb/sec Fibre Channel connections into one 4Gb/sec or two 1Gb/sec Ethernet ports into one 2Gb/sec).

A typical Fibre Channel Host Bus Adapter (HBA) will cost approximately $1500 to $3500. There are some cheaper models available ($700 to $900) but these often do not perform as well as they can introduce errors and reduce throughput.

A good fibre channel switch will switch all ports at full speed concurrently and this is why they are so expensive. $1000 a port is a pretty normal price for this type of equipment. However they often cannot handle sustained use on all ports at full speed (20 minutes and above would be a ceiling even on a Brocade Director FC switch). After this amount of time you will start to see errors which causes things to slow down a lot.
Also a FC switch requires transceivers (what you actually plug the cable into on the switch). It depends on the make, model and supplier as to cost of these. Sun sell the Brocade Director with a bag of them included in the cost however a HP Brocade Silkworm will be an additional $120 a transceiver from memory.

FC requires a fibre network which is expensive to put in, maintain, protect and is very easy to break. A piece of dust on a connector will create a lot of errors and drag the speed right down.

FC data blocks are very large (often Megabytes in size) rather the Ethernet packets which are usually measured in kilobytes. If you are using fibre channel and you are sending small requests (4 KB) all the rest of the packet is wasted space. This makes FC only suitable for large requests (i.e. open that 50MB file, not 500 of those 300KB files).

FC also has very little in the way of control traffic. This significantly increases the speed of FC however this only works on the principle of minimal errors during data transfer. This is why fibre channel is dependent on high quality gear.

iSCSI does not work very well over FC. No one has quite worked out why yet. Head technicians at Sun have been working on this issue for the last two years without working out exactly why.

iSCSI handles the small requests very well as it is Ethernet based but it also manages to handles the large data packets very well (FC will beat it but not by a lot). iSCSI also manages to handle the break up of the large SCSI blocks into TCP packets well and resize packets quickly to suit.

Binding TCP (or any protocol based on Ethernet) will be detrimental to speed of a Fibre Channel network. It would not be uncommon to see about a 60% loss of expected speed.

A lot of this stuff is a little irrelevant as all OS's used as storage devices have caches for this exact reason. A typical NAS will carry 1-2GB's of cache so that it can receive/pre-read the files and pump them across when required. So overall performance often comes down to OS configuration more than network bottlenecks.

For storage the most important thing normally is IOPS (Input/Output per second) which is the number of requests you can handle per second. This is typically what defines how fast the data copy is completed more than the throughput especially in mid-large multi-user scenario's. A typical SATA drive will give you approximately 120 IOPS where as a SCSI does approximately 250. For a comparison Fibre Channel drives can do as high as 1100 IOPS.

I spent eight months with HP and Sun in labs doing this and found the following (from my notes). Tests were done with data in memory so there was no disk read/write time, this is based purely on data transmission.

A well setup ethernet network running iSCSI will cost about $310 per machine (single connection, CAT6 incl NIC, cable and switch) and will pass a 300MB file in 0.2 sec either side of 3.4 sec without caching on either device receiving or sending. If you step up the NIC cost (total cost per machine $860 approximately) you can drop this to about 0.1 either side of 2.2 sec.

A well setup FC network will cost about $3400 to $3800 per machine (single connection, Fibre cable, HBA, switch, HBA software) and will transfer a 300MB file 0.14 sec either side of 1.2 sec without caching on either device receiving or sending

However there was typically additional costs with Fibre such as the need to install a 19" rack as a Brocade FC switch is full depth (approx 800mm depth and 1U high). Fibre also must be properly installed and the ends cooked and polished at approximately $90 per end. Ethernet switches are more shallow and CAT6 is more robust so installation costs for Ethernet is far lower.
These costs are also dependent on you buying a number that matches the gear. i.e. if you have 9 machines using FC then you only need HBA's, cables, software and transceivers for 9 however you must still buy a 16 port switch (at a total cost of approximately $16,000, or $1,800 per machine). FC switches come in 8, 16, 24 and then you typically step up to enterprise gear where you add ports to a switch chassis in sets of 8 or 16. Ethernet typically comes in 4, 5, 6, 8, 12, 16, 24, 32, 48 ports and then the enterprise gear where you add ports to a switch chassis in sets of 16 or 24.

In short Fibre Channel was made for (and is best for) SAN and backups (using SCSI devices as it is pure SCSI commands over a network). Ethernet and iSCSI are best for any thing else including Network Attached Storage (NAS) and device to device communication.