Monthly Archives: October 2011

HP-UX fasdm fails with vx_nospace

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HP-UX file systems can be extended with a combination of the lvextend and fsadm commands. It’s well known procedure that has been in widespread use for several years, allowing online file system extensions, ie. the file system can be extended while it is mounted and busy. The file system type must be of type “vxfs” and enclosed in an LVM logical volume.

Occasional difficulties can occur if the file system is 100% full. I recently encountered the following vx_nospace error when trying to extend a file system from 9 Gb to 59 Gb under HP-UX 11.31. Continue reading →

http_proxy in Red Hat 5

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This post is about setting the http_proxy environment variable in Red Hat 5. Newer versions of the OS allow the variable to be set in either of two ways, that is:

# export http_proxy=http://192.168.1.100:8080
# export http_proxy=192.168.1.100:8080

Both will work. A subsequent call to yum will read the http_proxy environment variable and act on it, using the named proxy to obtain a network connection to the relevant repository. I have tested this successfully on Red Hat 5.7.

Yum Failures

Older versions of Red Hat 5 are more fussy. RHEL 5.4 will allow the first form above (export http_proxy=http://192.168.1.100:8080), but use the second form and yum will barf extravagantly, leaving you with a lengthy Python trace back. Continue reading →

Root Password Recovery on a Sparc LDOM

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If the root password for a Unix system is lost or forgotten, it can be very difficult to regain root access and perform further administration work. Often it will be impossible. You could be lucky – there might be a user account with sudo access, or even a root shell still open on the system somewhere, for example on the system console. If the system is x86, you might be able to boot it from a live CD and restore root access by doctoring the root disk. Otherwise, with most systems (physical and virtual), it will often be a case of rebuilding the system from scratch.

Solaris is a bit different. It has long been possible with Solaris to regain root access by booting the physical system from a Solaris installation CD, mounting the original root disk and removing the root password string from the relevant file, usually /etc/shadow. The same technique works, surprisingly, with SPARC virtual systems, aka LDOMs. Proceed as follows. Continue reading →