mcr at sandelman.ca
Sun, 29 Apr 2007
A critique of "agile" and an interesting response
Steve Yegge has a nice rant about -isms, including the agile movement at:
http://steve-yegge.blogspot.com/2006/09/good-agile-bad-agile_27.html
Everything he says is correct, but he misses the point. All things that are apparently effective will have also-rans. The whole .com era was about that!
He says that he's observed a lot, but doesn't give us details. I'd like to know them. I don't think he's actually ever pair programmed, and no, ten people at a keyboard is not better.
The revolutionary thing about the XP methodology (XP is just one of many agile methods), was that it wasn't revolutionary. It just gave me language to discuss what I'd already been doing.
He then goes on to discuss the google agile methodology. It sounds great.
But, the best response I was pointed to is at:
http://www.xprogramming.com/xpmag/jatBaseball.htm
We Tried Baseball and It Didn't Work Ron Jeffries 05/02/2006 An allegory? Sarcasm? Humorous pastiche? You decide.
The fanatical proponents of baseball tell us that it is a very exciting game, fun to play and fun to watch. They are clearly either stupid or evil or both, because we tried baseball and it didn't work. ...
posted at: 20:17 | path: /agile | permanent link to this entry
Fri, 20 Apr 2007
Despite what the thread at: http://www.mail-archive.com/linux-raid@vger.kernel.org/msg07378.html
says, William L. Thomsom Jr. is reporting a real bug.
[root@grouper dev]# fdisk -l /dev/sda | grep sda6 /dev/sda6 2 4865 39070048+ fd Linux raid autodetect [root@grouper dev]# fdisk -l /dev/sdb | grep sdb6 /dev/sdb6 2 4865 39070048+ fd Linux raid autodetect root@grouper dev]# mdadm --create --verbose /dev/md1 --level=mirror --raid-devices=2 /dev/sda6 /dev/sdb6 mdadm: /dev/sda6 is too small: 0K
Yet, making ONE adjustment changes things:
[root@grouper dev]# fdisk -l /dev/sdb | grep sdb6 /dev/sdb6 2 4865 39070048+ fd Linux raid autodetect [root@grouper dev]# fdisk -l /dev/sda | grep sd.6 /dev/sda6 2 4865 39070048+ 83 Linux [root@grouper dev]# mdadm --create --verbose /dev/md1 --level=mirror --raid-devices=2 /dev/sda6 /dev/sdb6 mdadm: size set to 39069952K mdadm: array /dev/md1 started.
Curiously, that's all I had to do. Subsequent partitions (I had 8 of them to raid), just worked. Likely this is a bug in the kernel, where once one partition has been used, it winds up caching the disk label, and therefore some other effect no longer occurs.
Oh:
[root@grouper dev]# uname -a Linux grouper.sandelman.ca 2.6.18-1.2239.fc5xen0 #1 SMP Fri Nov 10 13:58:27 EST 2006 i686 i686 i386 GNU/Linux
Why would I make 8 40G partitions on each of a pair of 320G disks? And then raid pairs, and then add them all to an LVM?
Well... imagine that I get some bad sectors somewhere. That means that my RAID will get degraded to single disk. If I want to continue working, and not replace the disk immediately, it turns out that I can find another 40G on another platter rather easily, and raid that together instead of the piece that I lost.
Then I'll look at SMART and other info, and find out if the disk is really dying, and try to get it replaced, but in the meantime, I feel more safe.
If, while waiting for the replacement disk, I got a second failure, in the other disk (both disks are, same vendor, and probably sequential out of the assembly line), then I'd loose everything... unless I can just degrade part of each disk, and keep working.
[root@grouper dev]# mdadm --create --verbose /dev/md7 --level=mirror --raid-devices=2 /dev/sda7 /dev/sdb7 mdadm: size set to 39069952K mdadm: array /dev/md7 started. [root@grouper dev]# mdadm --create --verbose /dev/md8 --level=mirror --raid-devices=2 /dev/sda8 /dev/sdb8 mdadm: size set to 39069952K mdadm: array /dev/md8 started. [root@grouper dev]# mdadm --create --verbose /dev/md9 --level=mirror --raid-devices=2 /dev/sda9 /dev/sdb9 mdadm: size set to 39069952K mdadm: array /dev/md9 started. [root@grouper dev]# mdadm --create --verbose /dev/md10 --level=mirror --raid-devices=2 /dev/sda10 /dev/sdb10 mdadm: size set to 39069952K mdadm: array /dev/md10 started. [root@grouper dev]# mdadm --create --verbose /dev/md11 --level=mirror --raid-devices=2 /dev/sda11 /dev/sdb11 mdadm: size set to 39069952K mdadm: array /dev/md11 started. [root@grouper dev]# mdadm --create --verbose /dev/md12 --level=mirror --raid-devices=2 /dev/sda12 /dev/sdb12 mdadm: size set to 39069952K mdadm: array /dev/md12 started. [root@grouper dev]# mdadm --create --verbose /dev/md13 --level=mirror --raid-devices=2 /dev/sda13 /dev/sdb13 mdadm: size set to 39069952K mdadm: array /dev/md13 started. [root@grouper dev]# pvcreate /dev/md1 Physical volume "/dev/md1" successfully created [root@grouper dev]# pvcreate /dev/md7 Physical volume "/dev/md7" successfully created [root@grouper dev]# pvcreate /dev/md8 Physical volume "/dev/md8" successfully created [root@grouper dev]# pvcreate /dev/md9 Physical volume "/dev/md9" successfully created [root@grouper dev]# pvcreate /dev/md10 Physical volume "/dev/md10" successfully created [root@grouper dev]# pvcreate /dev/md11 Physical volume "/dev/md11" successfully created [root@grouper dev]# pvcreate /dev/md12 Physical volume "/dev/md12" successfully created [root@grouper dev]# pvcreate /dev/md13 Physical volume "/dev/md13" successfully created [root@grouper dev]# vgcreate Grouper1 /dev/md1 /dev/md7 /dev/md8 /dev/md9 /dev/md10 /dev/md11 /dev/md12 /dev/md13 Volume group "Grouper1" successfully created [root@grouper dev]# vgs VG #PV #LV #SN Attr VSize VFree Grouper1 8 0 0 wz--n- 298.06G 298.06G VolGroup00 1 24 0 wz--n- 76.25G 6.16G [root@grouper dev]# pvs PV VG Fmt Attr PSize PFree /dev/md0 VolGroup00 lvm2 a- 76.25G 6.16G /dev/md1 Grouper1 lvm2 a- 37.26G 37.26G /dev/md10 Grouper1 lvm2 a- 37.26G 37.26G /dev/md11 Grouper1 lvm2 a- 37.26G 37.26G /dev/md12 Grouper1 lvm2 a- 37.26G 37.26G /dev/md13 Grouper1 lvm2 a- 37.26G 37.26G /dev/md7 Grouper1 lvm2 a- 37.26G 37.26G /dev/md8 Grouper1 lvm2 a- 37.26G 37.26G /dev/md9 Grouper1 lvm2 a- 37.26G 37.26G
posted at: 02:23 | path: /oss | permanent link to this entry
Mon, 09 Apr 2007
I discovered that the default /dev/MAKEDEV does not create the xbd2 device entries, so a NetBSD domU does with three disks does not get initialized properly by default.
Normally, you run "cd /dev && ./MAKEDEV xbd2" and you are done.
But, now that NetBSD has an mfs based /dev, the results are not saved.
The problem is that if you edit /dev/MAKEDEV with vi, it renames the file, which means that it creates a new file in the mfs. (It is mounted with union option). Really, I think that the mfs /dev should be mounted below the real /dev, and also created elsewhere, so that one can decide of the node should be permanent or not.
I could have mounted the / on another virtual machine (one nice thing about virtual machines), but NFS exporting / to another NetBSD machine and mounting it (which it gets the underlying /dev), and running MAKEDEV was easier.
posted at: 12:34 | path: /colo | permanent link to this entry
Mon, 02 Apr 2007
Quirks and Quarks gets it wrong
This is what my play list says about the Quirks and Quarks downloads.
Quirks & Quarks - CBC Radio - QQ-170207-01-Obesity Quirks & Quarks - CBC Radio - QQ-170207-02-Bird Butts Quirks & Quarks - CBC Radio - QQ-170207-03-Peregrine Recovery Quirks & Quarks - CBC Radio - QQ-170207-04-Moth Antennae Quirks & Quarks - CBC Radio - QQ-170207-05-Question-Frozen Carbonation Quirks & Quarks - CBC Radio - QQ-140207-01-Censorship in Science Quirks & Quarks - CBC Radio - QQ-140207-02-Giant Clams Quirks & Quarks - CBC Radio - QQ-140207-03-Ancient Agriculture Quirks & Quarks - CBC Radio - QQ-140207-04-Dusty Planet Quirks & Quarks - CBC Radio - QQ-140207-05-Columbus Silver Quirks & Quarks - CBC Radio - QQ-030307-01-Walking on The Moon again Quirks & Quarks - CBC Radio - QQ-100307-01-Peruvian Sun Towers Quirks & Quarks - CBC Radio - QQ-100307-02-Smart Scrub Jays Quirks & Quarks - CBC Radio - QQ-100307-03-Origin of Lice Quirks & Quarks - CBC Radio - QQ-100307-04-AEGIS Quirks & Quarks - CBC Radio - QQ-100307-05-Cowbird Mafia Quirks & Quarks - CBC Radio - QQ-100307-06-Question, Lightbulb Lifespan Quirks & Quarks - CBC Radio - QQ-170307-01-Mars Ice Quirks & Quarks - CBC Radio - QQ-170307-02-Chimp Tools Quirks & Quarks - CBC Radio - QQ-170307-03-Bone Printer Quirks & Quarks - CBC Radio - QQ-170307-04-Hearing Mammals Quirks & Quarks - CBC Radio - QQ-170307-05-The Elephant's Secret Sense Quirks & Quarks - CBC Radio - QQ-240307-01-BC Algae Quirks & Quarks - CBC Radio - QQ-240307-02-Dinosaur Burrows Quirks & Quarks - CBC Radio - QQ-240307-03-Modified Malarial Mosquitoes Quirks & Quarks - CBC Radio - QQ-240307-04-Friendly Monkeys Quirks & Quarks - CBC Radio - QQ-240307-05-Herzberg Winner - Bond Quirks & Quarks - CBC Radio - QQ-310307-01-Sugar Fuel Quirks & Quarks - CBC Radio - QQ-310307-02-Kuiper Collision Quirks & Quarks - CBC Radio - QQ-310307-03-Marmoset Chimera Quirks & Quarks - CBC Radio - QQ-310307-04-Wind Hunter Quirks & Quarks - CBC Radio - QQ-310307-05-E. coli and Chimps Quirks & Quarks - CBC Radio - QQ-310307-Questions- Body Temperature
What's wrong with this?
This is because the "album label" says:
[Quirks & Quarks - Dec. 16, 2006] [Quirks & Quarks - Dec. 2, 2006] [Quirks & Quarks - Dec. 23, 2006] [Quirks & Quarks - Dec. 30, 2006] [Quirks & Quarks - Dec. 9, 2006] [Quirks & Quarks - Feb. 10, 2007] [Quirks & Quarks - Feb. 17, 2006] [Quirks & Quarks - Feb. 24, 2007] [Quirks & Quarks - Feb. 3, 2007] [Quirks & Quarks - Jan 6, 2007] [Quirks & Quarks - Jan. 13, 2007] [Quirks & Quarks - Jan. 20, 2007] [Quirks & Quarks - Jan. 27, 2007] [Quirks & Quarks - Mar. 10, 2007] [Quirks & Quarks - Mar. 24, 2007] [Quirks & Quarks - Mar. 31, 2007] [Quirks & Quarks - March 17, 2007] [Quirks & Quarks - March 3, 2007]
This is a plea for sanity. YYYY-MM-DD.
Please.
posted at: 21:46 | path: /standards | permanent link to this entry
