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TODO

update grade not-z scripts to handle/be aware of winter terms
update system page for (new)www
scripts to write:
- user homedir backup pruning script
- deploy studentlistcreate as a cron job once again
- machine backup pruning script
- status page monthly cycle script
- revive gimmeh script, now that text access seems possible
manual pages to write:
- lab46 usage tutorial
  - include mercurial repository checkout info
  - include irc class chat tutorial
- data structures, sll/dll library functions as their own manual pages

URLs

Some links of interest:

Other Days

November 19th, 2019

pi4b dual head issues

Attempting to set up a fresh raspbian install on the pi4b. Strangely, getting issues with dual head: it is only coming up in mirrored mode (or when I play with it, not at all).

The only major variables that have changed:

new raspbian release (I could test my old setup.. that is easy enough to verify)
no longer using HDMI monitors, but the DVI connections on the LAIR monitors.
- further investigation suggests the pi may be seeing identical EDIDs and other monitor ID things, so it is defaulting to a mirroring mode.
- tvservice -l consistently identifies two displays, so the hardware sees it, the software is not.

Interestingly: my old raspbian setup IS working properly. So what is different between the two?

March 15th, 2018

Setting up the raspberry pi 3 for use in the comporg class. Named it pi3b, and will get the IP of 10.80.2.48; running the latest stable release of rasbian.

Looking to get LDAP and autofs going, then installing packages to make it minimally functional for our purposes.

March 6th, 2018

Aside from an attempt at restarting my status-reporting habits in January of 2017, I totally neglected it for the remainder of the year.

So here we go, attempting another go. Will we be successful?

pods configured for better SSD operation

In other recent projects, I encountered some useful configuration options to improve performance, and avoid some anti-longevity side-effects of default settings.

I ended up taking a Debian USB installer, booting each pod in rescue mode, getting to a prompt, and running the following on EACH:

# umount /
# tune2fs -O ^has_journal /dev/sda1
# tune2fs -o discard /dev/sda1

Then on the master nodes, I enhanced both /etc/fstab and /etc/rc.local as follows:

# /etc/fstab: static file system information.
#
# <file system> <mount point>   <type>  <options>         <dump>  <pass>
/dev/sda1       /               ext4    noatime,nodiratime,discard,commit=600,errors=remount-ro 0       1
tmpfs           /tmp            tmpfs   defaults,noatime,mode=1777 0 0
tmpfs           /var/log        tmpfs   defaults,noatime,mode=1777 0 0
tmpfs           /var/spool      tmpfs   defaults,noatime,mode=1777 0 0
tmpfs           /var/tmp        tmpfs   defaults,noatime,mode=1777 0 0

Note how I put the log files in RAM too (on the pods)… this should greatly reduce extraneous writes.

Then at the bottom of /etc/rc.local, I added:

#!/bin/sh -e
#
# rc.local
#
IPADDR=
while [ -z "${IPADDR}" ]; do
        IPADDR=`/usr/local/bin/iface | /bin/grep -v 'lo' | /usr/bin/head | /usr/bin/cut -d' ' -f2`
        sleep 1
done
/bin/hostname `/usr/bin/host ${IPADDR} | /usr/bin/cut -d' ' -f5 | /bin/sed s/\.$//`
/usr/bin/host ${IPADDR} | /usr/bin/cut -d' ' -f5 | /bin/sed s/\.$//  > /etc/hostname
echo "${IPADDR}    `cat /etc/hostname`"                              > /etc/hosts
echo "127.0.0.1    localhost"                                       >> /etc/hosts
echo "10.80.2.46   lab46.g7n.org lab46.corning-cc.edu"              >> /etc/hosts

echo deadline > /sys/block/sda/queue/scheduler
echo 1 > /sys/block/sda/queue/iosched/fifo_batch

exit 0

As the deadline scheduler has frequent mention of usage with SSDs.

Useful URLs:

lab46too SSD updates

With the pods having seen their SSD updates, I am looking to do the same for lab46too, testing to make sure the similar changes can be applied to that machine before rolling them over to lab46 proper.

I've updated the /etc/fstab and /etc/rc.local files accordingly on lab46, so those changes have been synced over to lab46too on a recent rsync run.

I had to remove the commit=600 from the /home partition. For some reason it didn't want to mount with that.

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