GKrellM is a GTK-based stacked monitor program that charts SMP CPUs, disks, load, active net interfaces, and internet connections. There are also builtin monitors for memory and swap, file systems with mount/umount feature, mailbox checking including POP3 and IMAP, clock/calendar, laptop battery, sensors (temperatures, voltages, and fans), and uptime. It has LEDs for the net monitors and an on/off button and online timer for PPP. There is a GUI popup for configuration, plugin extensions can be installed, and many themes are available. It also features a client/server monitoring capability.
LCDproc is a utility to drive one or more LCD (and LCD-like) devices attached to a host. It is comprised of a server, which uses a modular device driver system to control attached displays, and one or more clients to gather data as appropriate and send screen data to the server. The included client displays a multitude of system statistics (CPU/memory/disk usage, uptime, date and time, temperature, etc.). Multiple clients can connect to the server simultaneously, and clients can set priorities on the screens they provide to influence in what order items are displayed. This facility can also be used to "pop" critical screens (such as an entry from syslog from a log-watching client). All functionality is implemented in userland. Support for many display devices and several platforms (Linux, *BSD, and Solaris at least) is included.
syslog-ng is a syslogd replacement for a wide variety of UNIX systems that supports IPv6 and is capable of transferring log messages reliably using TCP and SSL and filtering the content of messages using regular expressions. Both RFC3164 and RFC5424 style messages are handled, but more esoteric formats like BSD process accounting logs are supported too. Apart from regular text files, it supports storing messages into SQL and MongoDB databases, and forward messages to local processes via pipes or UNIX domain sockets. This makes syslog-ng ideal as an integration platform. syslog-ng supports extracting structured information from the traditionally text based syslog via csv-parser(), db-parser(), and patterndb. Tag based classification, rewriting messages, and outputting messages in JSON is also possible. This makes syslog-ng ideal for preprocessing events for further analysis, be that home-grown scripts or SIEM systems. syslog-ng scales well on today's multi processor and multi-core systems: reaching 1,000,000 messages per second is a reality for the simplest use cases.
GlusterFS is a clustered filesystem capable of scaling to several petabytes. It aggregates various storage bricks over Infiniband RDMA or TCP/IP interconnect into one large parallel network file system. GlusterFS is based on a stackable user space design without compromising performance. It allows access via Swift API, SMB, NFSv3, QEMU/KVM, OpenStack Compute, OpenStack Block Storage, Xen, CloudStack, HDFS API, oVirt, and more, all in a unified backend which enables multiple, simultaneous access points to the same data stores.
DansGuardian is a Web content filtering proxy that uses Squid to do all the fetching. It filters using multiple methods including, but not limited to, phrase matching, file extension matching, MIME type matching, PICS filtering, and URL/domain blocking. It has the ability to switch off filtering by certain criteria including username, domain name, source IP, etc. The configurable logging produces a log in an easy to read format. It has the option to only log text-based pages, thus significantly reducing redundant information (such as every image on a page).
Dnsmasq is a lightweight, easy to configure DNS forwarder and DHCP server. It is designed to provide DNS and (optionally) DHCP to a small network. It can serve the names of local machines which are not in the global DNS. The DHCP server integrates with the DNS server and allows machines with DHCP-allocated addresses to appear in the DNS with names configured either in each host or in a central configuration file. Dnsmasq supports static and dynamic DHCP leases and BOOTP/TFTP for network booting of diskless machines.