If you have ever tried to use a new Fedora or RHEL to build packages for older systems you may have run into errors at installation time. For example, if you were to roll a package on Fedora >=10 or RHEL >=6 and tried to install it on RHEL 5 you will get rpmlib(FileDigests) errors. …
Category Archive: linux
Dec
20
2009
On topics such as how to run sudo from a cron job
If you want to run sudo from any part of a cron job make sure you comment out the Defaults requiretty from /etc/sudoers. Bit me twice now so hopefully I’ll remember next time. Ed: Apologies to those who have read this before but I had to restore from backup and my last post wasn’t in …
Mar
02
2009
Solid State Devices (SSD) and journaling
A few things all of us are probably interested in: SSD Write Amplification: http://www.extremetech.com/article2/0,2845,2329594,00.asp Journaling and write performance in ext4: http://thunk.org/tytso/blog/2009/03/01/ssds-journaling-and-noatimerelatime/ The bottom-line as far as wear and tear: vfat is basically the same as a journaled FS from a wear-leveling standpoint, both are worst case. Thankfully vfat, being the worst case, forced the manufacturers …
Oct
21
2008
My favorite shell completion of all time…
My favorite BASH shell completion of all time is hostname completion for all of my favorite commands: SSH_COMPLETE=( $(cat ~/.ssh/known_hosts | \ cut -f 1 -d ‘ ‘ | \ sed -e s/,.*//g | \ uniq | \ egrep -v [0123456789]) ) complete -o default -W “${SSH_COMPLETE[*]}” ssh scp sftp rsync nmap traceroute ping nslookup …
Oct
02
2008
Red Hat RHN SSL certificate verification error
I was trying to connect to RHN from Yum/up2date in Red Hat Enterprise Linux 5. I kept getting fatal invalid SSL cert errors. The strange part – out of all of the machines I tested it was only occuring on a single RHEL 5 laptop. The really strange part – it was happening on the …
Oct
02
2008
Deleting All Messages in Exchange OWA
Ran into a problem with Exchange. I created a server-side rule to place spam messages in a folder that didn’t exist. All spam was instead going to the root folder, the folder above my inbox. Well if you use Entourage to access Exchange you will not be able to access this folder. If you go …
Mar
08
2008
Server Migration
It’s been three years since we upgraded the hardware that hosts our various sites. I contacted my provider (Crucial Paradigm) and got some competitive offers. Stefan, my friend in Berlin that I split the server with, and I agreed on the following specs: Athlon 64 x2 4000 (2 cores @ 2.1GHz, 512K L2 each) 4GB …
Nov
11
2007
PS3 hypervisor partitioning
I’ve been thinking of researching the PS3 hypervisor. Mainly from a security perspective but this led me to thinking. You know what would be cool? Micro-partioning a PS3. Obviously IBM has experience with micro-partitioning on the PPC and the Linux distros are already tried and tested in these exact environments. You could use the system …
