Question: How to delete the files which are older than n days WITHOUT use find command? For some reason, the find command is not used to check which files are older than n days, as a substitute, ‘tmpwatch‘ can be used The syntax is: # tmpwatch [time in hours] [directory] For example, to delete files […]
Fedora
Beginners Guide to Global File System 2 (GFS2)
Global File System 2 (GFS2) Global File System 2 (GFS2) is a cluster file system interfacing directly with the kernel VFS layer. This means that the same file system can be mounted and used by multiple cluster nodes simultaneously, while still providing a full regular file system, including features such as support for POSIX ACLs, […]
Managing Clustered Logical Volumes in RHEL Cluster (pacemaker)
Clustered LVM Clustered LVM allows the use of regular LVM volume groups and logical volumes on shared storage. In a cluster configured with clustered LVM, a volume group and its logical volumes are accessible to all cluster nodes at the same time. With clustered LVM, administrators can use the management benefits of LVM in conjunction […]
How to monitor the status of dm-multipathing and multipath devices (path groups) in Linux
Monitoring The multipath command can be used to monitor the status of multipaths. When used with one -l option, it will show a quick overview of multipath topologies. If the -l option is specified twice (-ll), it will also perform a check on all paths to see if it is active. If everything is fine, […]
Understanding Linux multipath (dm-multipath)
What is multipathing? Multipathing allows the combination of multiple physical connections between a server and a storage array into one virtual device. This can be done to provide a more resilient connection to your storage (a path going down will not hamper connectivity), or to aggregate storage bandwidth for improved performance. As an example, the […]
How to change the default permissions on /var/log/audit/audit.log file in CentOS/RHEL
Question: How to configure auditd to change the default permissions on the /var/log/audit/audit.log from 0600 to 0640 and also changing the group ownership of the file? By default it’s not possible to change permissions on the /var/log/audit/audit.log file using ACLs, instead “log_group” parameter can be set under the file /etc/audit/audit.conf. The Steps In this example, […]
A File Is Claimed to Be Disappearing – How to monitor a file for deletion in Linux
Question: A file seems to be disappearing and no direct reason for its disappearance can be found. How can we monitor the file access, especially the deletion of a particular file in CentOS/RHEL system? A file can be monitored through its lifecycle by using the Linux auditd service. The Steps 1. To install it on […]
How to Stop Audit Log Entries Written to System Logs in CentOS/RHEL 6
This post explains how to stop audit log entries written to system logs. 1. Check the file /etc/audisp/plugins.d/syslog.conf. By default, the file “/etc/audisp/plugins.d/syslog.conf will have the below line. args = LOG_INFO This will allow syslog to log audit logs into /var/log/messages. In addition audit.d will log all the audit events to /var/log/audit/audit.log too and this […]
/var/cache/yum Constantly Filling Files System in CentOS/RHEL
This post explains how to free up space when files under /var/cache/yum is filling up the disk space. This is normal behavior as the cache would increase its size based on the frequency of syncing with the yum server. Its an administrative task provide adequate space. This should be corrected by either running: # yum […]
How To Retain Current And Older Linux Packages While Doing Update With ‘yum’ Command
In this post, we shall discuss about how to retain current and older Linux packages while updating the Linux OS with the ‘yum’ command. Note that /etc/yum.conf configuration file contains a [main] section. If required then we can add many additional options under the [main] section. Some of the key-value pairs in the [main] section […]