Archive
Posts from 2005
Testing SSL services
If you manage web applications and servers, you may have encountered a poorly written application or a web server that periodically hangs for no reason. These issues usually pop up out of the blue, and most people rely on their user community to notifiy them when problems are detected. To ensure timely notifications when these problems occur, I developed ssl-service-check. ssl-service-check is written in Bourne shell, and uses the OpenSSL toolkit to connect to a service and issue a "GET /." If the service fails to respond, ssl-cervice-check will log an error to syslog and send an e-mail to the address defined in the global ADMINS variable…
$ read more →Viewing t.v. program listings
While checking my daily news sources, I came across a review of several opensource t.v. program listing applications. If freeguide adds a search feature in a future release, I will definitely check it out (that way I can easily locate Seinfeld reruns).
$ read more →Adding mirrors to Veritas Volume Manager volumes
One of the cool features of Veritas Volume Manager (VxVM) is it's ability to change the layout of a volume on the fly with vxasssist(1m). This option has helped me numerous times, especially when I needed to mirror volumes that weren't mirrored. Given the following unmirrored striped volume: We can easily add a mirror by invoking vxassist(1m) with the "mirror" option: The mirror option accepts a layout option and several keywords to control the layout of the new mirror. In this example we used a 3-column striped plex to match the layout of the existing plex…
$ read more →Accessing metadevices in single user mode
While perusing Sunsolve today, I came across an infodoc that described how to access metadevices in single user mode. I have never needed to perform this operation, but was happy to learn for future reference! :)
$ read more →Determining the reason behind rx_overflow values (part 1).
While performing some routine checks on one of the servers I support, I noticed numerous input errors on Gigabit Ethernet interface zero: Since this was a Sun server running Solaris 9, I fired up the kstat(1m) utility to find the cause of these errors: After reviewing the kstat(1m) output I noticed that the rx_overflow value was well in excess of 150k. Since the word "overflow" is never a good sign, I started to research this issue by reading the manual page for gld(7D). This page contains descriptions for the generic LAN driver (gld) kstat values, but for some reason didn't include a description for rx_overflow (the name is self-evident, but I wanted a definite answer). After a quick Google search I came across the following information in the the Sun Maximizing Performance of a Gigabit Ethernet NIC Interface blueprint: "When rx_overflow is incrementing, packet processing is not keeping up with the packet arrival rate…
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