Posts from 2009

Getting the Linux NetworkManager process to respect custom DNS server settings

networkingSep 14, 2009 1 min read

I recently switched my work Desktop from Ubuntu to Fedora 11, and noticed that there are some new configuration options now that network intefaces are managed by the NetworkManager process. Two useful options are the ability to specify the DNS servers and search domains in the network-scripts files, and have those applied when a DHCP lease is acquired (this assumes you override the values provided by your DHCP server). To override the DNS servers and search domains, you can set the DNS1, DNS2 and DOMAIN variables in your favorite ifcfg-eth[0-9]+ script: Hopefully the NetworkManager is all it's cracked up to be. Only time will tell of course…

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Listing packages that were added or updated after an initial Fedora or CentOS installation

linuxSep 13, 2009 1 min

I was reviewing the configuration of a system last week, and needed to find out which packages were added after the initial installation. The rpm utility has a slew of options (you can view the list of options by running ) to query the package database, including the extremely handy INSTALLTIME option. Using this query value along with my pkgdiff script, I was able to generate a list of packages that were installed (or updated) after the initial install: Now this doesn't take into account package updates, but it should be pretty easy to identify which items were added vs. updated with a couple more lines of shell script (you could cross reference the package list above with /root/install.log if you need to get super specific).

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Why partition X does not end on cylinder boundary warnings don't matter

storageSep 12, 2009 2 min

While reviewing the partion layout on one of my hard drives, I noticed a number of "Partition X does not end on cylinder boundary" messages in the fdisk output: This was a bit disconcerting at first, but after a few minutes of thinking it dawned on me that modern systems use LBA (Logical Block Addressing) instead of CHS (Cylinder/Head/Sector) to address disk drives. If we view the partition table using sectors instead of cylinders: We can see that we end at a specific sector number, and start the next partition at that number plus one. I must say that I have grown quite fond of sfdisk and parted, and they sure make digging through DOS and GPT labels super easy.

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Better ZFS pool fault handling coming to an opensolaris release near you!

storageSep 11, 2009 1 min

I just saw the following ARC case fly by, and this will be a welcome addition to the ZFS file system!: OVERVIEW: Uncooperative or deceptive hardware, combined with power failures or sudden lack of access to devices, can result in zpools without redundancy being non-importable. ZFS' copy-on-write and Merkle tree properties will sometimes allow us to recover from these problems. Only ad-hoc means currently exist to take advantage of this recoverability. This proposal aims to rectify that short-coming…

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Dealing with cron bad user messages on Solaris hosts

solarisSep 11, 2009 1 min

While reviewing the cron logs on one of my Solaris hosts, I noticed a number of entries similar to the following: These errors are typically generated when the account the job run as doesn't exist, or when the user's shadow entry is locked (locked accounts have a LK in the /etc/shadow password field). In this specific case a password or NP entry (the account doesn't have a password, and logins are denied) wasn't assigned to the arr user, so the account was still listed in the locked state. Setting a strong password fixed the issue, and everything is working swimmingly!

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