This is how to do a simple file system increase in Logical Volume Manager. For example, increasing /tmp from 512 Mb to 1 Gb.
/tmp is a logical volume:
# df -h /tmp
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/mapper/vg00-tmpvol
496M 19M 452M 4% /tmp
Running “vgdisplay /dev/vg00” showed that volume group vg00 contained 3.5 Gb of free space. Extended the logical volume with lvextend: Continue reading
After a customer had performed some bad edits on various LDAP configuration files, users were locked out and unable to access the system. Root could still login however.
I logged in as root, and rather than mess with various config files, eg under /etc/pam.d, ran this command to disable LDAP authentication and enable “normal” authentication using /etc/shadow: Continue reading
Running sshd in the foreground can be an effective way to debug ssh problems. In the following example, a user was unable to access a remote system using ssh keys. Running sshd in debug mode provided a quick resolution. Both source and target systems were Solaris, but the same method applies equally to Linux. Continue reading
The Sheevaplug is a small ARM based “plug computer” manufactured by GlobalScale. This post explains how to connect over the serial connection for out-of-band access. A bit like connecting to the server processor of a unix server, or the alom/ilom of a Sun/Oracle box, or the Vsphere console of a vmware system.
Connect a USB cable from your PC to the sheevaplug’s micro USB port (also called the “JTAG” port) and proceed as below. Continue reading
Working on a client site recently, I noticed their Apache error log had grown to 32 Gb in size. The file was being written to at a rate of a quarter of a million lines a day, propelled by various cron jobs set up to run every 5 minutes. A PHP reconfiguration fixed the problem.
The box was a Solaris 10 system running “License Watcher“, and those messages was all coming from the License Watcher php code. Not genuine errors, just repeated diagnostics. I edited /usr/local/php/lib/php.ini and changed this line Continue reading
Here’s a quick script to show duplicate files on Linux. It should cope with arbitrary spaces in file names, and to save time and CPU resources, it will checksum only files of the same size.
Usage: Save the script to dups.sh or whatever, then run it with no arguments. A list of duplicated files is output.
Continue readingThis is a quick review of the Fedora 18 XFCE spin running on 64 bit intel, followed by a few post-install tips. Continue reading
For capacity planning, it is useful to know how much free resource is available on a given LDOM server. That is, a “parent” system hosting several guest LDOMs. For example, if you want to know how many more LDOM’s the server could support. Continue reading
If sar is enabled on your Solaris 9 or 10 box, but does not seem to be recording any data, check the following.
Check the cron log /var/cron/log for errors like this:
! bad user (sys) Tue Apr 27 08:30:00 2012
Continue reading
I had a customer complain of this error when trying to become ‘oracle’ user on a Red Hat 4.4 server:
[user@redhat ~]$ sudo su – oracle
Your account has expired; please contact your system administrator
/bin/su: incorrect password
The cause was that the password for the oracle account had expired (nothing to do with the user’s own account). The chage command can be used to list account expiry and password ageing information: Continue reading