How do you know if your computer has a virus? Is it connected to the Internet? Then it has a virus. Many computer viruses and other malicious applications are very resilient and will actively resist any attempts to deactivate and remove them. Some viruses can even delete your antivirus application or prevent it from working properly. Many viruses cannot be effectively removed once they are loaded in memory and active.

Until I branched out a few years ago from supporting Unix server to working with Linux clusters, I never really encountered this issue: you type “reboot”, “init 0″, or “shutdown” as root and… nothing happens. Or the system starts going down but then hangs on unmounting a filesystem or unloading a module. I think this happened once to a colleague of mine who was rebooting a Solaris server, but this is a common problem with Linux.

Recently I upgraded a client’s Vista computer (Toshiba Qosmio, 4Gb, Intel Core Duo P7350, 7200-RPM 200-Gb disk) from Vista Ultimate 64-bit to Windows 7 Ultimate 64-bit. Being a Unix sysadmin this is not something I usually do. How did the experience compare to upgrading HP-UX, Solaris or SLES? In a nutshell: I’d rather walk around all day in wet underwear than attempt to upgrade Vista ever again.

NetBackup is an enterprise-level distributed backup and recovery application. The environment consists of the master server, media server, storage library, networking hardware, and client agents. NetBackup supports a wide variety of Unix, Linux, VMS, and Windows systems. The original backup solution was developed by Control Data Corp., later acquired by Openvision, which gave the product its “NetBackup” name. NetBackup was then bought by Veritas and is currently owned and supported (poorly) by Symantec.

I am sure this will sound familiar: you are copying a large amount of data – either locally or over the network – and you are wondering how long it will take and if there is a way to make things go faster.You may be surprised, but it does matter what type of files you are copying: 1Gb-worth of many small files will take considerably longer to copy than two 500Mb files. The hardware you are using is an important consideration, but it’s not the only factor limiting data transfer speed.

Bonnie++ is a benchmark utility designed to test performance of hard drives and filesystems by simulating various types of disk I/O. Bonnie++ may be used to test local disks as well as network-mounted filesystems. It …

Suppose you are working with a Web server and your task is to make sure that no files or directories have permissions “777″. It would be easy to just recursively change permissions for all files …

When performing a new Unix OS installation you are usually presented with a choice of accepting the default partitioning layout or going into advanced settings and defining your own partitions. The default layout will normally …

Below are some basic steps to secure a wireless access point (WAP). The screenshots are for Linksys WAP54G v. 3.04, however, the same steps will apply to wireless access points from other manufacturers. Understand this: …

Some users and application developers believe that any free disk space on the server belongs to them. Suddenly you get an email alert saying that a server “xyz” ran out of disk space in /home. …

Normally I don’t concern myself with Windows- related matters. However, the infamous Bagle rootkit and its numerous variations deserve some attention even from Unix sysadmins. Bagle annoyed me and my customers long enough. Essentially, Bagle …

This is a quick-and-dirty guide to recovering VxVM volumes and filesystems on a Solaris server. These instructions are not intended to be an in-depth troubleshooting guide for the Veritas Volume Manager. This is just something …

The cost of storage arrays is falling along with the quality of their manufacture. To quote Lev Andropov from the “Armageddon”: “Components. American components, Russian Components, ALL MADE IN TAIWAN!” What in the nineties used …

The following is a procedure for recovering a ReiserFS filesystem with bad blocks. If this is a system FS and cannot be unmounted, the box needs to be booted from the latest version of Knoppix …

The this is a description of a method for recovering ReiserFS filesystems from failed disks with bad blocks, when other recovery methods (reiserfsck) will not work. For this example, the failed server is called node1 …

Medussa is a password cracking application that supports distributed processing. One node acts as the Medussa server and the rest of the nodes are running the client application. The server node, in addition to running …

The following condition was originally discovered in OpenSolaris 11 (Bug ID: 4697677). This problem occurs when you do mkdir -m 700 on a mountpoint before mounting it. This superceeds whatever permissions you might give …

Rather than rebuilding an Informix database on the new HP-UX server, it possible to migrate the existing installation from the old server. The database resides on raw disks with transparent volumes that are not visible …

A quick note on creating large JFS filesystems on AIX: if the filesystem is 64Gb or might be expanded to over 64Gb any time in the future, make sure the NBPI (Number of Bytes Per …

Several Veritas VM and system logs can be used to monitor and diagnose problems with the Volume Manager. An automated script can be used to grab the last few lines from these logs whenever a …

NFS is a relatively uncomplicated functionality of any Unix system. However, from time to time you are bound to run in the “permission denied” error while trying to NFS-mount a filesystem. Everything seems to be …

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