bad timing

Previously, I had my fileserver sync time with my primary wireless router and some pool.ntp.org servers. Then I noticed this:
Jul  7 08:41:10 remote  /usr/sbin/ntpd[521]: skew change 255.181 exceeds limit
Jul 7 08:56:48 remote /usr/sbin/ntpd[521]: skew change -34.707 exceeds limit
Jul 7 09:24:28 remote /usr/sbin/ntpd[521]: adjusting local clock by -0.159868s
Jul 7 09:24:28 remote /usr/sbin/ntpd[521]: skew change -32.121 exceeds limit
Jul 7 09:39:06 remote /usr/sbin/ntpd[521]: adjusting local clock by 0.465410s
Jul 7 09:39:06 remote /usr/sbin/ntpd[521]: skew change 132.634 exceeds limit
Jul 7 09:44:23 remote /usr/sbin/ntpd[521]: adjusting local clock by 0.727679s
According to the documentation, there's no real-time clock on most OpenWrt compatible hardware. I guess when you consider the minimalistic setup of these devices, you can't expect everything.

I've now switched it around. My routers now sync with my fileserver and us.pool.ntp.org. My fileserver ignores the access points and syncs with:
server timex.cs.columbia.edu
server ntp-2.cso.uiuc.edu
server ntppub.tamu.edu
server ntp-1.vt.edu
server ntp3.cs.wisc.edu
server 0.pool.ntp.org
server 1.north-america.pool.ntp.org
server 2.us.pool.ntp.org
Those are the same NTP servers I use at work, with 3 pool.ntp.org servers thrown in. It just annoys me that OpenNTPD doesn't have the equivalent of "ntpq -p" to check the status of the NTP sync.


Remote backups with rdiff-backup

I set this up a while back, but I needed to make some notes on my setup of rdiff-backup that backs up my colo'd PC to my home fileserver. I've been using it for more than 3 months and it has done a great job - space efficient, time efficient and bandwidth light. I followed the recommended unattended HOWTO and it was easy to setup - even with different OSes (Solaris x86 vs. CentOS), versions of ssh and versions of rdiff-backup itself. Only modifications were:
  • In the authorized_keys2 on the source system, I didn't include the from="kitty" bit as the destination PC that I'm pulling from has a dynamic IP
  • I included --print-statistics in the cron job's command line, redirected the output to a logfile
  • I setup the three config files/scripts setup to have LogWatch tell me the daily summary of the rdiff-backup results. i.e.:
    • /etc/log.d/conf/logfiles/nyc-backup.conf
    • /etc/log.d/conf/services/nyc-backup.conf
    • /etc/log.d/scripts/services/nyc-backup
My next step is to get rdiff-backup setup to backup by local fileserver. Right now I have a simple rsync from one drive to the other. The reason I haven't done it yet is that the filesystems were setup without LVM (what was I thinking!). So, I need to clean up, reformat with LVM and then get rdiff-backup setup - maybe even with the snapshot recommendations on the unattended HOWTO page.

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