Tag: centos

Linux Disk Utilization – Reducing Size of /var/log/sa

We occasionally get alerted that our /var volume is over 80% full … which generally means /var/log has a lot of data, some of which is really useful and some of it not so useful. The application-specific log files already have the shortest retention period that is reasonable (and logs that are rotated out are compressed). Similarly, the system log files rotated through logrotate.conf and logrotate.d/* have been configured with reasonable retention.

Using du -sh /var/log/ showed the /var/log/sa folder took half a gig of space.

This is the daily output from sar (a “daily summary of process accounting” cron’d up with /etc/cron.d/sysstat). This content doesn’t get rotated out with the expected logrotation configuration. It’s got a special configuration at /etc/sysconfig/sysstat — changing the number of days (or, in my case, compressing some of the older files) is a quick way to reduce the amount of space the sar output files consume).

DNF — What Provides This File?

“Dependency hell” used to be a big problem — you’d download one package, attempt to install it, and find out you needed three other packages. Download one of them, attempt to install it, and learn about five other packages. Fifty seven packages later, you forgot what you were trying to install in the first place and went home. Or, I suppose, you managed to install that first package and actually use it. The advent of repo-based deployments — where dependencies can be resolved and automatically downloaded — has mostly eliminated dependency hell. But, occasionally, you’ll have a manual install that says “oh, I cannot complete. I need libgdkglext-x11-1.0.so.0 or libminizip.so.1 … and, if there’s a package that’s named libgdkglext-x11 or libminizip … you’re good. There’s not. Fortunately, you can use “dnf provides” to search for a package that provides a specific file — thus learning that you need the gtkglext-libs and minizip-compat packages to resolve your dependencies.

SCP From Solaris to RHEL?

Evidently you cannot just scp files from an old Solaris box when you’re on a RHEL/CentOS system … there’s an incompatibility between them that requires you to (1) install scp1 on the Solaris server {not likely in a prod environment} or (2) use sftp to transfer the files.


Server1: Red Hat Enterprise Linux Server release 7.6 (Maipo)
Server2: Solaris 5.9

lisa@server1:~/$ scp lisa@server2:/data/stuff/file1.txt ./input/
lisa@server2’s password:
scp: warning: Executing scp1.
scp: FATAL: Executing ssh1 in compatibility mode failed (Check that scp1 is in your PATH).