LTSP Client with HPLIP

I had a problem hanging a HP printer off an LTSP client. This printer – M1132 – requires a proprietary plugin.

First, I tried to setup the printer using USB-IP. This obviously worked. The LTSP server was successfully fooled into thinking that the printer was connected to the local USB port. However, this method was troublesome as USB-IP needs to be manually connected each time the client was rebooted.

Then, I tried the recommended way to do it by editing lts.conf to enable jetpipe and saned. Unfortunately, while both the daemons started up, it was not possible to neither print nor scan from the client. When I ran hp-setup from the LTSP server, it failed to even detect a network printer. While sane was able to detect the scanner, it too failed to scan.

Next, I tried to run hp-setup from within the LTSP chroot but that was not possible either as lsusb failed to return anything inside the chroot. Therefore, the HP software is unable to install the plugin nor configure the CUPS queue.

Finally, the way that I got things to work was to manually install the plugin and setup CUPS. This involves running hp-plugin from within the LTSP chroot. Then, I installed the PPD and configured both the cupsd.conf and printer.conf manually. Then, all I had to do was add a network connected IPP printer on the LTSP server and point it to the client.

Voila, both scanning and printing now works with the printer hanging off the client.

PS: In order to prevent CUPS from running on any of the other clients, I made CUPS listen to the specific IP address assigned to that specific client.

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HD Video Streaming on LTSP

Our office uses a LTSP setup for workstations. On a lark, I decided to measure how well it worked with streaming video.

Screenshot - 10282014 - 11:25:22 AM

As can be seen from the screenshot of nmon running and measuring the network bandwidth, the maximum peak transfer is 120MBps which translates to about 1Gbps. This is the amount of bandwidth taken when streaming a Youtube video on full-screen.

At this bandwidth, the video is perfectly watchable with no noticable lag or refresh rate problems. However, if we merely watch the video in cinema mode, the bandwidth requirement drops to about half. If we watch it in the normal mode, the bandwidth reduces by another half.

So, to watch smooth Youtube videos on LTSP, we will need about 250Mbps network bandwidth. On a 100Mbps network bandwidth, video was choppy even at the standard Youtube video size. There were noticeable frame rate problems.

This also means that we will need high amounts of bandwidth at the LTSP server end to provide smooth videos to a number of workstations via a gigabit switch. Therefore, it is advisable for the LTSP server to have multiple nics in a bonded configuration.