'Borrowing' IPv4 netblocks to get around address space exhaustion
I recently read a news story speculating that a black market in IPv4address space would develop as the IPv4 address space became exhausted(which is allegedly happening fairly rapidly). In reading the story, itstruck me that we could see an even more interesting and evil trick usedby sufficiently desperate and underhanded organizations: just borrowingunrouted netblocks.
The trick goes like this. First, find a suitably sized netblock that isallocated but appears unrouted; then, find yourself a compliant ISP andget them to 'accidentally
Retrospectives are uncommon
Something I have been mulling over as a result of this entry (and being prompted to write it) is how uncommonretrospectives are in writeups of things. Over the years in all of theusual sources, both old and new, I've seen quite a lot of writeups ofthe form 'this is the shiny thing that we've implemented and here is ourshort term experiences'; heck, I've written any number of them myselfhere on WanderingThoughts . But I've not seen very many
A little vi twitch
I am not the world's most sophisticated user of vi, but I have a numberof little twitches. One of them is that I never use either ZZ or :wq ;instead I always use :w and then :q . I know the commands, but I justdon't like them for the fundamental reason that they're not vi commands.
Well, obviously they're vi commands in one sense. But they aren't in thesense that they break the rules of vi commands
Why diskless Unix machines lost out
A long time ago, diskless Unix machines were all therage. These days, they've all but vanished (although theylive on in some specialized applications, such as LTSP ). Frommy perspective, what made diskless machines lose out is threefold:performance issues, cheap disks, and complexity. Of these, the realkiller issue was complexity.
The hard core of the performance issues is not so much how fast asingle machine could access its 'disks' (although this should not beunderestimated itself)
SSL certificate vendors are selling a commodity
Here is something important to understand about SSL certificates inpractice: regardless of what SSL vendors tell you and how they try tomarket themselves, they are fundamentally selling a commodity, namelySSL certificates that work in all significant environments and browsers.
(If they are not selling this commodity you don't want anything todo with them unless you have very specialized needs.)
Some vendors will present themselves as more trustworthy, but this ishogwash. No user actually notices what vendor you use; you are lucky ifthey
The right way and the wrong way to disable init.d services
First, a quote from the (Ubuntu) manpage for update-rc.d (pointedout in the comments on a recent entry ):
The correct way to disable services is to configure the service asstopped in all runlevels in which it is started by default. In theSystem V init system this means renaming the service's symbolic linksfrom
StoK.
Here is one difference between a developer and a sysadmin:to a developer, something is disabled if it only runs harmless code oronly runs code
Oracle's future for Sun's hardware and OS business is now clear
The alternate title for this entry is 'how to persuade us to never buyyour hardware again'.
The old Sun had both a general server business and a general OSbusiness, and people used both; they bought Sun servers to run lotsof operating systems and they ran Solaris on lots of non-Sun hardware.It is now clear that Oracle is nothing like this. Solaris nowexists only to run on Oracle hardware ,and Oracle hardware exists only to run Solaris and a few otherOracle-supported operating systems
The right way to fix ZFS disk glitches (at least for us)
Every so often in our environment of ZFSpools with mirrored vdevs, we will have an iSCSI disk drop outtemporarily. When this happens, ZFS winds up faulting the disk with readand write errors, and you get to fix this after the disk is back.
In theory, this is fixed with just ' This is a grump. Dear packagers of software for Linux distributions, please note this:just because I have your software installed does not mean that I wantto run your daemon. Database systems, I am especially looking atyou. Please package software accordingly, and please make sure thatdaemons stay turned off and not running even when harried sysadminsapply package upgrades. Since the natural way for a harried sysadmin to make a daemon not runis to turn off its init.d script (with In light of my last entry , here is aninteresting question: when do you know that a filesystem is consistent,and how much work does it take for the system to keep track of this? First off, there are some easy cases, namely filesystems withjournaling, strong ordering guarantees, or copy on write properties. In general, copy on write and journaling filesystems are supposedto be consistent all of the time unless the kernel has detected thatsomething is wrong and flagged the filesystem as damaged. Instead ofthese zpool clear
Dear software packagers, startup scripts edition
chkconfig on Red Hat derived
Keeping track of filesystem consistency
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