Preferred disk layout for Linux servers

With age comes wisdom? After working with SoftwareRAID and Linux servers for a while, I've changed my preferred disk system design and layout.

RAID

Under the old system, I was running a (2) disk RAID1 (mirror) with a hot-spare disk setup and ready for action. But if you're going to have a hot-spare dedicated to the RAID1 array, why not use it as an active array member? That way, if a disk fails, you still have two good disks. Unfortunately, when a RAID element fails, the load from the rebuild process can often kill the one of the remaining disks in the array.

Is it a likely scenario? Probably not. But Linux's Software RAID handles a triple-active RAID1 mirror without any slowdown, so there's not much reason *not* to implement it that way. Plus it's a useful trick to know for situations where you really *do* need to be that paranoid.

(I'm not sure whether any hardware RAID cards provide for a triple-active mirroring RAID1 configuration.)

Partitions

I've also simplified how many partitions I like to have on the disk. My current disk layouts typically look like:

/dev/sdX1 - /dev/md0 - 250MB - /boot
/dev/sdX2 - /dev/md1 - 12GB - / (primary root)
/dev/sdX3 - /dev/md2 - 12GB - / (backup root)
/dev/sdX5 - /dev/md3 - 32GB - /var/log
/dev/sdX6 - /dev/md4 - 2GB - swap
/dev/sdX7 - /dev/md5 - 64GB - /backup/system
/dev/sdX8 - /dev/md6 - (remainder) - LVM area

During normal operations, we boot and run /dev/md1 as our / (root) partition. The /dev/md2 partition is kept offline and is never mounted. Periodically, after validating that the server is in good health, we will copy the contents of /dev/md1 to /dev/md2, make adjustments to /etc/fstab and the hostname. This requires some server downtime (long enough to setup the 2nd root partition).

In the case where the primary OS is hosed, we can boot from the backup OS partition and get back up and running quickly. That gives us the luxury to continue operations until we can schedule downtime to fix the primary OS partition.

Notice that I've broken /var/log out to its own partition. I do this so that an overflowing set of logs won't take the server box down. Plus, by putting the log files in their own physical partition, it's easy to use a boot CD or USB key to gain access to the logs in case of severe issues.

The other physical partition that I consider necessary is /backup/system. This partition is used to hold images of the boot and root partitions, along with information about the partition layout and images of the MBRs. Basically, it's used to store disaster recovery backups. You should not have this partition mounted during normal operations. Taking the contents of this partition offsite is also a good idea. A basic text file of how the backups were created along with information for how to restore these backups is recommended.

Summary

This setup tries to walk the fine line between keeping it simple, but having enough flexibility to deal with a large set of potential failures. Anything from a two-disk failure, to the primary OS being hosed, to both OS partitions having problems all the way up to boot records or the /boot partition being killed.

Ext3 Performance Tuning

The ext3 system is a great workhorse filesystem. Lots of tools, lots of distros that know how to read it, and it's pretty much the "safe" choice for almost all workloads. Still, there are things that the default ext3 doesn't do as well as it should so most installations need a little TLC.

For the most part, you should plan on shutting down a system before tuning it (after making backups!). Tuning doesn't take too long and is a lot simpler to do if the system is offline.

First off, you should check out your existing filesystem settings with:

# tune2fs -l /dev/hdXY

1) Directory indexing - Which helps ext3 deal with any directories that have lots of files. (See the Gentoo Forum link for explanations of why.)

# tune2fs -O dir_index /dev/hdXY
# e2fsck -D /dev/hdXY

The first command changes the ext3 system to use directory indexing for all new directories, the second command updates all existing directories.

2) Journal mode

# tune2fs -O has_journal -o journal_data /dev/hdXY

I prefer full journaled mode. The "-O has_journal" should be unnecessary (all ext3 file systems have journals after all) but probably ensures that things work if you accidently run it on a ext2 filesystem.

3) Journal size

This requires poking around a bit to find out what your current journal size is. First, you need to find the inode of the journal.

# tune2fs -l /dev/hdXY | grep -i "journal inode"
Journal inode: 8
# /sbin/debugfs /dev/md2
debugfs 1.39 (29-May-2006)
debugfs: stat <8>
Inode: 8 Type: regular Mode: 0600 Flags: 0x0 Generation: 0
User: 0 Group: 0 Size: 134217728
File ACL: 0 Directory ACL: 0
Links: 1 Blockcount: 262416
Fragment: Address: 0 Number: 0 Size: 0
ctime: 0x4658e77b -- Sat May 26 22:05:47 2007
atime: 0x00000000 -- Wed Dec 31 19:00:00 1969
mtime: 0x4658e77b -- Sat May 26 22:05:47 2007

In this particular case, for a 12GB partition, the journal size is 128MB (262416 blocks at 4096 bytes each, or look at the "Size:" field which is in bytes). On my 64GB partition, the journal size is also only 128MB.

So, do we want to muck with the journal size? Well, maybe... Doubling the size is probably okay, maybe even making it 4x larger. But beyond that and I think you'd want to tread carefully.

# tune2fs -J size=$SIZE /dev/hdXY

$SIZE is defined in megabytes, so for me to double the 128MB journal, I'd use a value of "size=256".

Ubuntu 11.04 Natty Narwhal

Ubuntu 11.04 (Natty Narwhal) has arrived, and we have the scoop on everything you need to know about Canonical's latest Linux, along with the usual review and benchmarks. Is this the change we've been waiting for, or is the Natty Narwhal a fail whale?

A couple of weeks ago, Canonical, the company behind Ubuntu, launched Ubuntu 11.04 'Natty Narwhal', one of the most highly anticipated and controversial desktop Linux distributions ever introduced. What makes Natty a landmark release is the inclusion of the brand new Canonical-developed Unity user interface. Unity replaces the GNOME 2 shell that served as Ubuntu's default UI since the distribution's inception.

Zoom

The timing of Canonical's decision polarized both the Ubuntu and GNOME communities, as the GNOME project also recently finalized GNOME 3. Ubuntu 11.04 was originally slated to use GNOME 3, along with the new GNOME 3 shell, as its default GUI. The GNOME 3 shell is no less a drastic departure from GNOME 2 than Unity, and popular opinion is split in all directions.

Zoom

As the most widely-used desktop Linux distribution, Ubuntu was a major driving force behind GNOME's adoption. Linux Mint is the second most popular desktop distribution, and an Ubuntu derivative. Mint will use GNOME 3 in upcoming releases, but without the GNOME 3 shell. Whether you're a fan of Unity or GNOME 3, one thing was always certain: Ubuntu was destined to change in a big way this spring.

But enough with GNOME and the political back-story; we have a whole lot of Ubuntu 11.04 to cover. This is such an atypical release that the question “What is Natty Narwhal?” cannot be answered simply.

Let's start with the meaning of Natty. Here in the States, Natty is short for Anheuser-Busch's bottom-shelf line of “Natural” beers. If you were ever a struggling student, there's a good chance you subsisted at one point on ramen and Natty Ice. Consequently, it has also come to mean cheap, trashy, or sub-par. How's that for a rough start?

And for that matter, what is a narwhal? I mean, look at that thing.

Zoom

Apparently, Canonical's name for this release gets worse. The word narwhal dates back to Norse seafarers who explored the Arctic waters where this horned beast lives. Narwhal quite literally means “corpse whale” because its skin resembles a water-logged corpse. Oof. Ubuntu 11.04: Cheap, Drunk, Dead, and Bloated.

Let's hope not!

We typically bring you an Ubuntu: Benchmarked and Reviewed article every April and October, but since Unity introduces such tremendous change to Ubuntu, there's a ton of new stuff to go over. Thus, we decided to include a full-on guide to the new OS. We have an installation walkthrough, a roundup of changes to the software, a spotlight on the graphical redesigns, a Unity tour, uTouch testing, keyboard/mouse shortcuts, and even a few essential tips to get you up and running in Ubuntu 11.04.

And of course we still benchmarked the new version of Ubuntu. However, this time there is a twist. Instead of testing Natty Narwhal against its predecessor (Ubuntu 10.10 Maverick Meerkat) and the latest LTS (Ubuntu 10.04 Lucid Lynx), we replaced Maverick with Natty. That's right; since Unity is the big deal in this release, we benchmarked Ubuntu 11.04 Natty Narwhal with Unity versus Natty Narwhal with the GNOME 2 shell, now referred to as the 'Classic' interface. We took this route to see if the new GUI has any performance implications. Ubuntu 10.04 LTS is still a part of our data to provide a comparison to the latest Long Term Support release.

Before we get into the numbers, let's kick this off with an installation walkthrough of Ubuntu 11.04 Natty Narwhal.

Kubuntu 11.04 Natty Narwhal - KDElicious

I'm not quick to change operating systems. In fact, I've been running pretty much the same distributions since ever, with only the version numbers growing. Ubuntu, SUSE, that's pretty much that. A bit of Gnome, a bit of KDE. KDE, you say? Well, way back then in days of old, I started with Kubuntu, switched to Ubuntu, and now there's Unity. Natty was not the sore disappointment I expected, but it sure isn't going to be my next desktop.

On the other hand, I did love openSUSE 11.4, with KDE4 finally managing to win my hard appreciation. With Gnome 3 making its unholy noise and Unity toying about like a sweet retard, the prospect of a future KDE desktop is becoming more relevant by the minute. There's only Mint that could make the difference, but if you want to stay with Ubuntu family, sans cousins, then you should take a look at Kubuntu, that is, Ubuntu with KDE.

Live session - Simple and inviting

Kubuntu comes with a few nifty tricks. The boot menu knows whether you're booting from CD or USB, and you can also configure persistence, which is cool. The live system is well laid out, polished and elegant, with a predominantly blue and gray theme that is similar to previous versions, and yet unique and fresh.

Wireless, Bluetooth and Samba sharing works. Desktop effects are not enabled by default, but you can start them manually. The experience is snappy, without lag, even on the elderly T60 machine with a fairly weak ATI card. But we will talk more about desktop effects a little later. Now, let's install Kubuntu 11.04 on the machine.

Installation - Elegant and hassle free

Kubuntu installation starts in a separate virtual desktop of its own, maximized, to reduce distractions. This is a nice touch. You also have the wizard steps listed on the left side, so you know what lays ahead of you. The one tiny discrepancy is the aspect ratio of the background image, which is scrunched to fit on the normal desktop, but it's untouched during the installation. Notice the big blue bubble on the right.

Like regular Ubuntu, it lets you update the system and grab proprietary software, so you end up with a system fully patched before you start using it. The installation begins as soon as you configure the partition table. You get lovely transition effects and a professional slide show, which feels even more complete than the original.

Kubuntu ships with GRUB 2 at version number 1.99ubuntu3, which features tiny fonts and a blue background in the menu. Not bad, but the fonts are too tiny to see. The dual-boot setup went without any problems.

Using Kubuntu Natty - Exceptionally smooth

Real fun begins after the installation. With no codecs in the live session, Kubuntu is much like Ubuntu and openSUSE, functional yet frugal. However, since you can install codecs and updates during the installation, you hit off immediately with a good and sensible experience.

Look & feel

In the installed system, desktop effects are enabled. The default theme is Oxygen. The bottom panel comes with a smart system tray area that works a tad better than other KDE distros. It's the small details that make all the difference.

Desktop effects

A delightful experience. Truly amazing. Tons of great plugins, just waiting for you to fiddle and play. Cube, Sphere, Snowfall, Expo, raised windows, cube caps, wobbly windows, explosions, Aladdin lamp, you name it. And not a hitch on an old laptop.

Applications

The default arsenal is decent. GwenView, LibreOffice, Okular, K3b, Amarok, and a handful more. No GIMP and no Marble. The selection is not the most exciting in the world, but it packs a decent bunch of professional, high-quality applications. We'll see some of these programs in action soon enough.



Firefox is not installed, but you can easily add it to your collection.

Instead, you get Reconq, which is the new version of Konqueror as the primary browser. While I'm really fond of Firefox, I truly suggest you give Reconq a try. It's slick and modern and fast. It's based on Webkit and it ranks 100/100 on Acid test. There's also a handful of extensions built-in, like the ad blocker. But then, it's your choice.


Desktop integration

Reconq is well integrated into the system. You'll get tiny notifications in the system area, which will inform you of possible upgrades for the browser. For example, extra plugins. The same applies to Amarok, Firefox and other software, though.

Multimedia

No worries. Flash's there, playing smoothly. MP3 support is there, too. Amarok really behaved well. You get Wikipedia info for artists, lyrics, album covers, and you have plugins for online podcasts and streaming services.

System resources, performance, battery life optimization

Despite being KDE, despite eating a handsome 500MB of RAM on a 32-bit machine, Kubuntu is snappy and responsive. This is a great surprise. With each new release, KDE4 behaves better, and Kubuntu 11.04 is no exception. In fact, despite its default performance mode, the aggressive settings do not harm the battery life. My initial tests shown an improvement compared to older versions, so we're now talking a most handsome four to five hours where previously I'd get three to three and a half on the same hardware.

Stability, suspend & resume

Putting the laptop to a gentle and recoverable sleep worked well. The system was quite stable save for a few almost religiously customary application crashes. Pardus remains the champ, with zero, unbeaten so far. More about that later.

Package management

Blazing fast, you get the full power of APT under the hood, true and reliable. Getting new software is extremely easy. Similar to what openSUSE does, and yet even smoother and faster. You can also set automatic updates. Comparing to Ubuntu Software Center, less fun in a way, but more aloof and professional.

Extras

Lots of the stuff you see in Kubuntu is not unique to this distro. And yet, lots of the stuff is tweaked ever so slightly to be simpler and friendlier than in other KDE4 systems. There are many examples, including TouchPad configuration, notifications, clipboard history, helper plugins for various programs, and more.

Smart desktop actions are there, and have been for a long time. For example, moving the active window against the right desktop wall will maximize it on the right half side. This has recently been embraced by Ubuntu, too. And you have widgets, if you fancy them.

Font installations are also quite simple and intuitive. New wallpapers can be installed without walking the perilous streets of the Internet. Right click on your desktop and search for new images, sorted by age, rating, downloads, or perhaps size.

System information is also presented in a manner that speaks to normal people. Again, this is small and seemingly unimportant thing, but when you're hunting for those missing drivers, you will appreciate the convenience. There's nothing magical about the data, but it's shown in a way less skilled users can relate. This is a very mature direction.

For Windows users, a transition to Kubuntu, or rather, KDE 4.6, will feel quite natural, as much of the stuff in Windows 7 has some KDE4 origins, so don't be fooled about what came first, the chicken or the egg, just enjoy the good work.

Bad things

On the same note, when things go wrong, they go wrong universally. Like openSUSE, Kubuntu suffers from the same Marble crash; try zooming in on a satellite view and the program dies. This is unfortunate, but BugZilla says it ought to be fixed soon. There was another instance of a crash, that of KSnapShot no less.

So Kubuntu has approx. the same level of trouble like its relatives. Printing isn't very simple, either. Fonts are decent, but openSUSE does it better; the default size is a bit too small for comfort. However, the rendering is quite good.

Extra extras

And just before we depart, a couple of lovely desktops:

Contemplating the future

You must be asking: What's best? What should you choose? openSUSE with KDE4? Mainstream Ubuntu with Unity? Perhaps Fedora with Gnome 3? Something else wearing Gnome 3 skin? Linux Mint Katya, with Gnome 2? Of course, Kubuntu 11.04 Natty Narwhal, how good is it, overall?

I still have not tested Linux Mint spring release, so I can't say for sure. However, considering the fact Julia was the best distro of 2010 and the Debian edition was surprisingly good, I'm most likely to be pleased. Then, openSUSE 11.4 KDE was a damn fine system and a marvelous surprise, too. Ubuntu Natty is neither here nor there, but surely not something power users will love. Gnome 3 is even worse. So if you ask me, if I had to choose right here, right now, Kubuntu is definitely one of the top choices on the Linux desktop market.

It's just as good as openSUSE 11.4 KDE, perhaps even a little better, plus you enjoy all of the benefits of the large Ubuntu user base. It's way better than Natty with Unity, that's for sure, and it outpaces any Gnome 3 system by seven and a half parsecs. Enthusiasm is all nice and good, but I believe I'm being cool-headed, objective and non-fanboyish when I say that Kubuntu is going to be one of my next desktops. There's only Katya left to check and try to see what it can do. But hey, the way I see it, it's going to be another good desktop and another great choice.

Conclusion

But let's focus on Kubuntu itself. Version 11.04 Natty Narwhal is fast, smart, elegant, polished, with a very decent performance, blazing desktop effects, good stability, and only a tiny bunch of bugs and issues. KDE4 crashes need to be resolved. Bigger default fonts would be nice too. Simpler printing, perhaps. But overall, it's almost perfect. There's a system anyone can use, from noobs to anti-noobs.

If you like Ubuntu but worry about Unity, worry no more. Here's the solution to all your woes. Kubuntu gets a splendid 9.9/10, and so I come a full circle since Dapper.

Cheers.

FreeNAS 8

FreeNAS is a popular FreeBSD-based operating system for network-attached storage (NAS). Thanks to the easy-to-use web interface, you don’t have to know anything about the FreeBSD base under the hood to share your files…

Pros: FreeNAS is an advanced NAS operating system with an easy-to-use web interface, especially if you love to use ZFS as your filesystem.
Cons: Due to the complete rewrite, FreeNAS 8 has lost some interesting functionality for home users, and upgrades from a previous FreeNAS release are not possible.
FreeNAS home

FreeNAS supports sharing your files using FTP, NFS, CIFS (Samba), AFP, rsync, iSCSI, and so on, and it also offers software RAID (0,1,5). With many advanced features, including Oracle’s ZFS file system, it’s the perfect companion to store files for your Linux desktop computers in a central place. Moreover, FreeNAS has very low system requirements, as it needs only 128 MB of RAM. This makes it attractive to blow the dust off an old Pentium 2 or 3 PC, put a couple of hard drives in it and make it a NAS. Of course, for high performance the machine still needs enough RAM and CPU horsepower, especially if you want to use ZFS, which needs a minimum of 4 GB RAM to offer some decent performance.

The installer is very basic, but extremely quick

The FreeNAS installer is bare-bones, but it gets the job done. Essentially, you only have to select the medium where FreeNAS will be installed. Note that FreeNAS needs a full disk for its own, so you can’t store any data on this disk. Therefore, it’s recommended to use a small disk (such as a USB stick or a CompactFlash device) for the operating system and add bigger disks to store your data. Installation is extremely quick, and after FreeNAS has booted for the first time, it shows you a simple menu in the console to set up your network configuration if this hasn’t already happened automatically. If the machine has been assigned an IP address (as you’re probably using DHCP on your home network), it also shows you the URL to access the web interface. Log in into this web interface with the username admin and the password freenas.

The web interface gives access to a plethora of information and settings. By default, you’re seeing tabs for system information, settings and some usage graphs. By clicking on the icons at the top or on the left, other tabs will be opened. The configuration settings give access to some really advanced features. For instance, the network settings even allow VLANs and link aggregation, and the iSCSI part in the settings is extremely comprehensive, allowing FreeNAS to act like a storage area network (SAN). All this can be done with a few clicks.

The new web interface gives access to all advanced features without becoming bloated


The central part of the FreeNAS configuration can be found in the Storage tab. The focus is on ZFS features, but you can still create UFS volumes if you don’t need the advanced features of ZFS or if your hardware is underpowered. If you select more than one disk when creating a new volume, FreeNAS automatically asks you if you want to group them as a mirror or a stripe. After this, you can replicate your ZFS datasets to a remote system, you can manually create snapshots of your data, and you can even schedule automatic periodic snapshot tasks, so you can always restore a previous version of a file.

FreeNAS 8 is a complete re-write of FreeNAS: the previous release was 0.7, which was based on FreeBSD 7.2 but had an architecture that was not flexible and modular enough to add new features. When the core developer announced that this led him to abandoning FreeNAS, the company iXsystems stepped in and announced it would take on FreeNAS development and give it the long-awaited re-write. This finally makes FreeNAS 8 a future-proof NAS operating system, based on FreeBSD 8. However, in the short-term this has some disadvantages, and you can see this clearly in this release: some functionality that was present in the previous FreeNAS release, such as iTunes/DAAP, BitTorrent and UPnP, has been taken out, and they will later be added as plug-ins in the FreeNAS 8.1 release. Also, it’s currently not possible to upgrade a FreeNAS 0.7 installation to the latest release, but the 8.1 release will get a migration utility that imports configuration settings and data volumes.

Periodically create ZFS snapshots to be able to restore previous versions of your files

Verdict: 4/5
iXsystems has turned FreeNAS 8 into a modern, modular and future-proof NAS operating system. The new web interface is really easy-to-use without hiding the advanced features. Unfortunately some features didn’t make it through the re-write, but they are promised to reappear in FreeNAS 8.1. All in all, this makes FreeNAS currently the most advanced NAS operating system for home networks.

BackTrack 5 : Great Exploit and Penetration Testing Distro

There are certain tools when you are a security consultant that are just crucial to your job. No matter how good you are, these tools will make you a lot better.

In the past couple of years one of the security tools that has risen to this rank is called Backtrack. It is a Linux based operating system that comes pre installed with a numerous amount of security programs on it.

It doesn't matter if you are a beginner or an expert you will find several tools that are installed on it that will help you.

In the past few weeks the newest version of the Backtrack operating system, version 5, has been released. There are several new things that the people who have used this operating system will love about the new release. There are also things about this release that will excite people who are new to the operating system as well.

In the following article I will discuss the Backtrack operating system in more detail and I will show how you can use it on your own system to secure it.

More details about the Backtrack operating system

As I said earlier this is a Linux based operating system that comes equipped with tons of security software that you might need. But there is a little more to it than that.

First of all, the software is not only installed but also optimized for the system. You will not have to worry about configuring the software to work on your system correctly.

The Linux installation that it is based on is known as Ubuntu. Ubuntu is known as being a very user friendly operating system. The installation also has several different UI configurations that you can use to get started. There is the gnome desktop interface and KDE interface.

If you are a new user then you might want to go with the Gnome interface since some people seem to think that it is easier. More advanced users might want to try the KDE version of the operating system. It gives you more options to configure the system.

There are several different aspects of the Backtrack operating system that allow it to be the tool of choice for security professionals. One of these is the amount of different categories of security that the operating system maintains software for.

These categories include information gathering, network mapping, vulnerability identification, web application analysis, Digital forensics, reverse engineering, and basic penetration.

So as you can see, no matter which part of the computer security field that you work in the Backtrack operating system should have you covered.

What is added with the number 5 version of Backtrack

When you install backtrack version number 5 you will find several things that are different compared to previous versions. The first thing that is different is that both KDE and the Gnome interface have been updated to the latest version.

Also you will find that the latest version of the Backtrack operating system is able to be installed in both 32 bit and 64 bit flavors. More and more computers are now 64 bit and Backtrack has upgraded to reflect that reality.

Another aspect of the new version of the Backtrack operating system is the fact that all of the software that came with it before has now been updated. The whole purpose of this operating system is to allow you to use the software that you need without any configuration.

If you have to keep track of the updates of these pieces of software then that would defeat the whole purpose. Instead the Backtrack operating system will update them for you every time there is a new version that is available.

Of course, if you want the newest version of the software you can install it yourself but with this system it is not necessary.

But it is not only the software that you use directly that has been updated. It is the software that is behind the scenes that has been updated as well. The drivers that you will need to use the Linux based system have been updated to the newest versions, especially the wireless drivers.

In the past, the Backtrack operating system has had a problem with drivers for different wireless cards that were installed on the user's computer. While this problem hasn't gone away completely you will find that it is a much easier situation to deal with. There are more wireless drivers included in the installation than ever before.

In this digital age, security is a concern since there’s the presence of hackers in the web. I guess its timely enough forBacktrack 5 (BT 5) or better known as “Revolution” to be released (just a few days ago).

Backtrack as we know is a Linux-based security distribution group which assists security professionals in assessing purely native environments dedicated to hacking. It’s also based on the Long Term Support (LTS) release of Ubuntu (version 10.04 or Lucid Linux) and utilizes the 2.6.38 Linux Kernel.

According to its developers, the software was built from scratch and improvements were added during the process. In addition, it has already been tested on both Motorola Atrix 4G and Xoom tablet device (functionality of the latest versionof ARM was tested).

If you’d been asking how BT 5 works, the answer is that it has a number of testing tools that both user and administrator can use. Currently, there are over 300 penetration-testing tools in BT 5 that comes handy in terms of testing items from web applications to RFID systems. Some of these tools are LAN and WLAN sniffers, password crackers, vulnerability scanners and the Metasploit exploit framework.

For those who are interested on BT 5, it’s already available for download on the software’s website.

For SAP Basis like me, there is great tools on this Backtrack 5 release which is SAP Exploit tools. Have a nice testing.

In conclusion

You will find that if you are a computer security consultant that there is no better tool to use than Backtrack. It has all of your favorite tools in one place ready for you to use.

If you own a company that has to store important data then it is vital for you to have a tool like this. That way your security people can be sure that they are testing your network with the same tools that the bad guys are using.