eclipse button problem

After upgrading to 9.10 many of eclipse's buttons stopped working. The fix is to export
export GDK_NATIVE_WINDOWS=1

It doesn't fix everything, but it lets it be usable again.

Grub Problem

I let a student use one of the lab machines to play with virtualbox, and then it stopped working with a grub error. So, I booted up with PuppyLinux and then try to rerun grub-install. It failed though and I think wiped out a bunch of files on the disk. It is unclear why, but about 1 Gig out of 8 is missing after I rebooted. Since it is close to the release of 9.10, I'm going to wait and try installing that to see if there are performance differences, but I wanted to make a note of this strange behavior.

networking device

ifconfig -a helped

need to check /etc/iftab, but another class is coming in

networking device

imaging problems

I tried reverting one of the machines to an earlier version, but it did not go well, which was strange. I tried to install the 6.06 version of Ubuntu that I had originally installed. It was having all sorts of problems though.

Later when I tried to copy another image back over to put it back to 8.04 for some reason the networking did not work. I checked the configuration a bit but it did not recognize the device at all. So, I'm trying to copy it back again. If not, then I might reinstall from a disk and then sync it up using dpkg --get/set selections.

Apache Error log

The error log was growing very fast, consuming all of the disk space due to students working on cgi programs.

I added a ScriptLogLength directive to apache.conf to restrict the max size of the file.

I also used the ScriptLog directive toput the file in the /tmp directory which should be more accessible to students.

trouble tickets

Installed request-tracker, it still seems like overkill, but we'll see if it is helpful.

trouble tickets

Installed request-tracker, it still seems like overkill, but we'll see if it is helpful.

Network monitoring

Trying to diagnose suspected problems with our network.

There don't seem to be any prepackaged diagnostic tools, so here is my current solution:

use netcat and dd to measure bandwidth, about once an hour
use udp packets with timestamps to measure latency about every two minutes, for this I'm using the Time::HiRes package to try to go down to micro seconds.

I'm measuring between machines in Hawkins 053b and 036b and within 053b.

Machine upgrades

Salvador would like to have graphics cards in the new lab machines to support csc451

Machine upgrades

Salvador would like to have graphics cards in the new lab machines to support csc451

dns

the multicast dns does not work well, which was causing hosts not to resolv
the fix was to remove [NOTFOUND=return] from /etc/nsswitch.conf

setting up wiki

setting up a new mediawiki:

installed some additional packages
setup the database
went very smooth so far

now to check into some plugins:
semantic wiki went easy
ldap was a bit of a pain, but I think I have it working
I ended up using a proxy to bind to the ldap and then needed to set a required group
to limit who could access the wiki

tasks - tried, but it looks to be based on mysql, there is not a lot of code, but I'm not
ambitious enough to port it tonight

open afs

working on getting afs installed

hmmm...
I need to think about how to handle the kerberos side

nfs testing

performance was poor today for students getting directory information,

testing again with iozone, but performance seems identical to earlier this year.

AFS

Trying out afs instead of nfs

raid

I had some problems with the raid.

Upon reboot I had lost the array configuration in the mdadm.conf file
then it did not want to take the sdc3 drive. The first problem dropped me into
single user mode on the reboot and then I had problems getting sdc3 back into the array. What I had to do was to start it without sdc3 and then readd it later.
It currently is rebuilding the spare.

Tonight I'll try some performance tests again to see if it makes a difference. It shouldn't but it would be nice to know.

Mediawiki

To edit the sidebar go to the page
MediaWiki:Sidebar

pdf concatenation

This worked for putting a bunch of pdfs into 1

gs -q -sPAPERSIZE=letter -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=out.pdf in1.pdf in2.pdf in3.pdf

(randomly found on the web)

pdf concatenation

This worked for putting a bunch of pdfs into 1

gs -q -sPAPERSIZE=letter -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=out.pdf in1.pdf in2.pdf in3.pdf 

uuid

Another tidbit that I do infrequently is have to look up the uuid of a drive.

One way to do it is using tune2fs -l /dev/sda3 or whatever

Mime decoding

When the scanner encounters a file it deems too big, it breaks it up into a couple of chunks. Unfortunately it does not do this nicely, rather it just truncates it and then sends a new message continuing where it left off.

Anyways, to reassemble
1. Save all of the parts into one file
2. Elide the headers out of the file except for the first one
3. Use munpack or mimedecode to get the pdf

Not too bad, but the extra editing is a little annoying

Dec 2009 update:
It works better if I view the email and then save it. The headers do not get saved to the file, which makes decoding go much better.

New server - nfs woes

The new server came in and I installed the new drives with no problem, although I will probably order another 90 sata cable next time. The raid setup went ok, I went with a raid 5. On doing the performance testing though (using iobench) the write performance was only about 10% of what we were getting previously. Locally on the machine the read and write performance is fine, but over nfs 3 it is terrible. Then I tried it over nfs to a partition that was not raid, and it was still terrible. So, the problem appears to nfs and not the physical setup.

My next step is to try openafs and hope that the performance characteristics of it will be sufficient.

Redcay Lab

Finished updating the redcay lab. It seems to be doing relatively well. They started acting poorly at the beginning of the semester, so upgrading went a bit slow, but I set up a prototype machine and then copied the partitions between machines. I had tried a whole disk transfer, but the machines have slightly different drive sizes, and the whole disk transfer did not work.

I had trouble doing the transfer under ubuntu, so I used a system recovery cd, which worked fairly well. The only trick was I needed to chroot to the new partition, then use mknod to set up the sda devices, then I could use grub to setup the boot partition.

One nice thing is that they now use fvm by default, so they are a bit more responsive.

Luma

I got luma configured for ldap editing instead of the ldapbrowser java program. It seems to be working ok. The ldapbrowser was not working well with the TLS protocol.

Luma

I got luma configured for ldap editing instead of the ldapbrowser java program. It seems to be working ok. The ldapbrowser was not working well with the TLS protocol.

Mime decoding

The scanner uses mime 64 when the pdf files get too big, which is a minor pain to decode.

uudeview seems to work reasonably well though.

firefox, nfs4

It appears that the new firefox's history mechanism, which uses sqlite to store the data, does not play nicely with nfs3. A locking issue hangs firefox on startup.

Looking into nfs4, it does not look very mature yet as a technology. The kerberos implementation looks ok, but is outside the scope of what we can provide without duplicating media services services. Without kerberos, it is not mapping the ids correctly, which is not viable for user directories.

Additionally, it gave me problems with exporting multiple directories. It only wanted to export one directory, and ignored the others...