# -*- coding: cp1252 -*-
from math import tan, pi, sqrt, log, floor
def eng(x, sigfigs=3):
m = floor(log(x)/log(10)/3)*3
LUT = {
-18: "a",
-15: "f",
-12: "p",
-9: "n",
-6: "µ",
-3: "m",
0: "",
3: "k",
6: "M",
9: "G"
}
return ("{0:.{1}g}{2}").format(x*10.0**(-m), sigfigs, LUT[m])
I’m not sure what grief the µ character is going to cause people. Feel free to change it to “u”.
I’ve been debugging why my printer won’t receive an IP from my dd-wrt router. (This is a beta version of Buffalo’s branded dd-wrt firmware: DD-WRT v24SP2-EU-US (05/25/11) std – build 17135.) I actually “upgraded” to the beta version while debugging this problem. Originally, I had the release version of Buffalo’s DD-WRT.
Anyway, to summarize, it seems like using dnsmasq as the DHCP server breaks things. When I set it back, all my clients get DHCP licenses. I learned this the hard way. First, my printer wasn’t getting an IP. So, I finally gave it a static IP. Then, an Android phone wasn’t getting an IP. At that point, I started dhcpdump and started snooping. Basically, it’d get an “address not available” error. I finally traced it down to the setting for dnsmasq on the dd-wrt page. Once I chose the regualar DHCP server (udhcpd) rather than dnsmasq, everything worked well:
here it is:
0 0 * * * root [ ! -f /tmp/wrtbwmon ] && wget "http://pastebin.ca/raw/2088536" -O /tmp/wrtbwmon && sed -i -e"s/.$//" /tmp/wrtbwmon && chmod +x /tmp/wrtbwmon
*/5 * * * * root /tmp/wrtbwmon setup br0
*/30 0-3 * * * root /tmp/wrtbwmon update /tmp/usage.db peak
*/30,59 4-8 * * * root /tmp/wrtbwmon update /tmp/usage.db offpeak
*/30 9-23 * * * root /tmp/wrtbwmon update /tmp/usage.db peak
45 */2 * * * root /tmp/wrtbwmon publish /tmp/usage.db /tmp/www/usage.htm
0 0 * * * root [ ! -f /tmp/ct2htm ] && wget http://pastebin.ca/raw/2089248 -O /tmp/ct2htm && sed -i -e"s/.$//" /tmp/ct2htm && chmod +x /tmp/ct2htm
* * * * * root /tmp/ct2htm
Couple of customizations here. First, I’ve modified the wrtbmon script to not rely on sort, since it doesn’t exist in Buffalo’s DD-WRT. Also, I’ve set up a small script to format ip_conntrack as HTML. This is so I can keep tabs to see if my QoS settings are working.
This all-in-one printer can scan to a Windows share. I have a Windows share hosted by Samba on FreeBSD.
Unfortunately, the printer/scanner intermittently (and pretty often) says it can’t find my FreeBSD machine when I–or more importantly my wife tries to scan a document.
I went pretty deep on this and took a packet capture:
More…
I recently installed subsonic, which has a Java dependency. The www/subsonic port installed Java.
Unfortunately, this (or something else I did) broke CrashPlan (which uses the Linux Java in the java/linux-sun-jre16 port).
I had to take a few unexpected steps to fix this.
More…
I’ve finally taken the time to figure things out step-by-step. NFSv4 ACL’s, which are supported by ZFS on FreeBSD (and Solaris) are pretty cool. However, I’ve never really understand how they work. By taking the time to use the command-line, I’ve figured out what I think is a good approach for a public share–one where I store old Recorded TV shows.
More…
My latest security schemees that I’ve mapped the Samba guest user to a new user “samba_guest”. I’ve made nobody the owner of public shares. I’ve removed the allow settings for the “nobody” user. I then enable everyone to read:
owner@:--------------:------:deny
group@:-w-p----------:------:deny
group@:r-x-----------:------:allow
everyone@:----Dd-A-W-Co-:f-----:deny
everyone@:rwxp--a-R-c--s:-d----:allow
Note that I’ve set up Samba with the ZFS ACL module. For each share, I’ve added the following entries:
vfs objects = zfsacl
nfs4:mode = special
nfs4:acedup = merge
nfs4:chown = yes
Just gathering bits of information on how to get this done:
The first set of instructions (for FreeBSD 7.x) was here:CrashPlan on FreeBSD HOWTO
This didn’t work that well on FreeBSD 8.x. There was some problem with epoll. The breakthrough came from Aaron here:
Add -Djava.nio.channels.spi.SelectorProvider=sun.nio.ch.PollSelectorProvider to the bin/run.conf for the engine.
Finally, here’s an rc.d startup script for Crashplan running on FreeBSD – 1st Byte Solutions.
When I tried starting crashplan manually, it initially had a hard time finding my /tank mount point. Seems like linux compat on FreeBSD didn’t want to mount it. I played around with a bunch of stuff, including trying out nullfs (I didn’t have that kernel module built, so I had to rebuild it). I’m not sure what I did (maybe built the nullfs module) but eventually, it was able to find my /tank mount point without doing anything fancy.
I’ve installed a FreeBSD system using gmirror onto a couple of USB drives. I’ve noticed that there’s a considerable lag when I’m doing certain things (running top for example). I’ve narrowed it down to the /tmp and /var file systems. These two file systems get written to often during normal system operation. I’ve recently aleviated this problem using the md facility–which creates a ramdisk.
Since I’m using USB drives for the root (a d the default /tmp and /var), the write latency is higher than read latency. In addition, gmirror exacerbates this tendency.
More…
Testing these drives: Newegg.com – Kingston DataTraveler 101 Gen 2 4GB USB 2.0 Flash Drive (Cyan) Model DT101G2/4GBZ
I got them free with some RAM. Here are the results:
-----------------------------------------------------------------------
CrystalDiskMark 3.0.1 (C) 2007-2010 hiyohiyo
Crystal Dew World : http://crystalmark.info/
-----------------------------------------------------------------------
* MB/s = 1,000,000 byte/s [SATA/300 = 300,000,000 byte/s]
Sequential Read : 22.563 MB/s
Sequential Write : 6.475 MB/s
Random Read 512KB : 23.013 MB/s
Random Write 512KB : 0.628 MB/s
Random Read 4KB (QD=1) : 5.609 MB/s [ 1369.3 IOPS]
Random Write 4KB (QD=1) : 0.005 MB/s [ 1.3 IOPS]
Random Read 4KB (QD=32) : 6.126 MB/s [ 1495.6 IOPS]
Random Write 4KB (QD=32) : 0.006 MB/s [ 1.5 IOPS]
Test : 1000 MB [F: 29.4% (1099.7/3737.0 MB)] (x9)
Date : 2011/02/09 2:02:07
OS : Windows 7 Ultimate Edition [6.1 Build 7600] (x86)
