Concert review Drivin' N Cryin'
Last year I did a number of concert reviews, but not nearly as many as I would have liked to. This year I plan to review 2 - 4 shows per month, and the acts will range from small local bands to large national headliners. I am also hoping to get peoples feedback from the shows, and take pictures if the venue allows them. So to start off 2009, I thought I would share my experiences from the Drivin' N Cryin' show I attended a few weeks back…
$ read more →Disabling synchronous syslogd updates
Most *NIX implementations ship with a syslog daemon, which is responsible for reading messages from clients and writing these messages to one or more log destinations. Most daemons perform this operation synchronously using the fsync() system call, which can lead to some headaches on super busy log servers. Linux has a nifty option to disable synchronous updates, which can really aide in scaling logging servers to handle lots and lots of clients. To disable synchronous updates (this can result in data loss, so make sure to evaluate all options prior to using this feature), you can prefix the log destination with a hyphen like so: This is super useful, and I wish there was a similar feature available out of the box for Solaris (syslog-ng can do this, but you shouldn't have to install another syslog daemon to get this functionality IMHO).
$ read more →Brendan Gregg screaming at a 7410!
Slashdot picked up a youtube video of Brendan Gregg, shouting at a Sun 7410. Its pretty halarious, but it does showcase just how cool the DTrace Analytics visual GUI is on Sun's new line of Amber Road products. Brendan is one of the co-authors of Solaris Internals, 2nd Edition. He also wrote the DTraceToolKit, which has allowed millions of SysAdmins who don't have the skills to deep dive into DTrace to harness its powa!
$ read more →Resource controls against fork bombs executed inside Solaris Zones
I came across this neat little tidbit on page 27 while reading through the pdf article *UNDERSTANDING THE SECURITY CAPABILITIES OF SOLARIS™ ZONES SOFTWARE As a test, I'm going to set this resource control on a zone and execute a fork bombto see what appears in system logs. This is pretty cool stuff! This parameter can be used, but should not be set so low that it impacts normal application operation. An accurate baseline for the number of LWPs for a given zone should be determined in order to set this valuable at an appropriate level…
$ read more →zpool shrink / evict is almost here
The inability to remove devices from ZFS Zpools has been one of the most annoying / inflexiable things about ZFS. I once read a blogpost about somenone who added a USB flash stick into the root ZFS pool, and now the USB stick became a perminent fixture of the machine! There was no simple way to fix this issue other than backup / network dump / rebuild machine / network restore. Matthew Ahrens workedon changing the ZFS scrub code in SNV 94 (which made its way into the Fishwork's Amber Road NAS Appliance), but this work will also lay the groundwork for "zpool evict" or the such…
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