UNIX Basics

OS X is built upon the UNIX Darwin kernel. Having a fundamental understanding of working the UNIX operating system can give you a great advantage of troubleshooting, tuning and general administration of your system. I have worked in many flavors of UNIX in the past 10 years which include SunOS, Solaris, IRIX, HP-UX, AIX, RedHat Linux, SUSE Linux and of course OS X. Each type of UNIX has its own uniqueness, different commands to manage system resources, etc. However, for the most part there is a lot of similarities among all these versions of UNIX. I wanted to list at least a couple of commands that may help you.

Parental Controls in Leopard

Parental Controls in Leopard is a really cool feature. I have this set up at home for the kids. I set up a special account for them so they can use the computer. Configuring Parental Controls is simple. Here are some screen shots:

Preparing for Disaster Recovery

Corporations spend millions of dollars per year designing, upgrading and maintaining their IT environment. The underlining infrastructure that supports these environments can be very complex, both from a technical and a compliance aspect of the business. This has encouraged IT managers to energetically implement virtual solutions to manage the replication and availability of critical data. Over the past several years, we have seen a tremendous growth in virtualization in many facets, operating system, network and storage to name a few. Virtualization has opened many opportunities for System Administrators replicate data over short and long distances in the form of images at the same time cut the amount of bandwidth and time constraints from traditional legacy methods.

Virtualizing tape libraries in the form of a VTL for disk – disk to tape backups is a very efficient use of resources. This allows Backup Administrators to easily plan, scale and administer new and existing solutions. Many organizations today are faced with regulatory compliances initiatives, such as SOX, HIPPA or GERPA to account and protect their data. These organizations often test their backups and schedule routine “fire drills” in which they attempt to restore their production environments offline or offsite. These isolated events turn into disaster when the controlled server fire is unmanaged and spreads rapidly to other parts of the data center, which results into a complete uncontrolled datacenter burn. Many systems are lost and if precautions are not attended to prior to the DR drill, an entire company can be wiped out in a matter of hours. Years of corporate data is lost and thousands of employees are out of work. This has a major impact on the economy. Unemployment rises which effects business and the local economy. When people are out of work, they look for other cost cutting measures. For example, they may turn off their heat and start burning wood to heat their home. Again, were back to burning. The emissions that are let out into the atmosphere from a wood burning fire place is unhealthy for the environment. Medical studies has shown that the emissions from a uncertified wood stove is 700 times riskier than that of a gas heated system.

Dr. Joel Schwarts stated “Particulate pollution is the most important contaminant in our air. …we know that when particle levels go up, people die. ” (Joel Schwartz, Ph.D., Harvard School of Public Health, E Magazine, Sept./Oct. 2002). This is serious business and should not be treated lightly. Because wood is heavy. This is primarily why Saw Mills use Semi Trucks to haul limbers down from the forest. When they cut down the tree’s, they are generally healthy tree’s that have matured to a state where they contribute to the environment. It is good to have trees. They clean our air. Big businesses however come in and partner with the saw mills to clear out these trees which help the environment to build factories and plants that pollute the air. So not only are we destroying the planet, we are contributing to the destruction of mankind through rapid growth and over population. Animals are loosing their homes. By destroying the livelihood of natures beasts, this results into a cataclymistic series of events because animals need to find alternate means to survive. Since most animals are dumb, by nature, they will die, resulting in loss revenue for fur coat manufactures. Because their fur is scrap at this point.

In conclusion, I feel that big business is bad for the economy.

The way I do backups

For those of you that know me, you already know that I am huge on data protection. I always backup. I have to admit, there has been times where I have been better at it than others, but suffice it to say, I have always had backups. During the last 10 years, I have used several methods that came and went (out the door) to perform my backups. Some of these included complex solutions with a tape library, Veritas (Symantec) NetBackup, or a korn shell rsync script to an offline disk. These all seemed to work for me, but never had the user friendly interface I really wanted in case someone else, other than myself had to recover a lost file.

I am really pleased with Apple’s Time Machine in Leopard. Time Machine offers a very friendly, easy to use interface to recover your lost data. That is why I like it.

HOW TIME MACHINE WORKS

I am very particular about what I backup, where, when and how long I want to keep it. By default, Time Machine will backup everything, including the Operating System files. The first time you run Time Machine, it performs a full backup to an external disk of all your data including the Operating System, then every hour perform an incremental backup of any file or directory that was modified. It will keep backups every day for a week, then keeps a weekly backups for a month and then continue backing up until your external disk is full. Since there are a lot of logs files, and other directories that are modified all the time at the Operating System level, I feel that it is not necessary to have Time Machine back these files up. I limit Time Machine to only backup the users home directory, basically their data only. This frees up a lot of disk space on the external drive and in time, saves money.

MY SETUP

As for the Operating System, I take a different approach. I have a Mac Mini that has two 1 TB Western Digital MyBook External Hard Drives connected via FireWire. I loaded the Mac Mini with Leopard Server, all the applications and patched it. I then connected one of the external 1TB drives and partitioned it into two GUID partitions, a 60GB and a 940 GB (roughly). Once the Mac Mini was set up the way I wanted it, (Apps, Apple Patches, etc) I cloned the Mac Mini to the 60 GB partition on the External Drive using the asr command in a Terminal Window and made it bootable. (/usr/sbin/asr –source / –target /Volumes/device –erase). I wanted to make sure that I was able to boot up off this drive, so I did so by shutting the computer completely down, powering it up while holding the option key and then selecting the external drive to boot from. Works like a champ, as expected. The idea is to have a perfect snapshot of the Mac Mini with the OS, patches and Applications. At anytime, I can literally take that external drive, hook it up to any Intel Mac and boot from it. This is great planning for upgrades and disaster recovery in the future. The other partition on that drive is for Time Machine Backups, which again is only backing up user data.

The other 1TB drive I have is used for user data only which obviously, goes with out saying gets backed up with Time Machine to the other external drive. Just to clarify, by default, the Mac will point the users home directory to the /Users folder. I point the users home directory to a folder called ‘Home’ on the external drive. In Leopard, it is easy to specify an alternate location. Simply go to System Preferences –> User Accounts and right click on the username and select ‘Advanced Options’. In there you can specify the path to the users home directory.

From time to time, I will be working with a file or directory I do not want to have backed up, such a big Movie files I am rendering or images I am working with in Photoshop. A good workaround I found is that I created a folder called Scratch. I exclude this folder in the Time Machine preferences as well as:

The System Files and Directories.
The users downloads folder
The Parallels Image
Microsoft Users Folder that contains my Entourage DB
Applications Directory
The users Trash Can

IN SUMMARY

I know it may seem like it may take a lot of work to get set up at first, and it does take some time, especially when initially building your system, creating the clone image and then selecting what you want to exclude from your backups. However, its really not that bad. In fact, its much easier than it may seem, just takes some time. What ever your method is to backup, I recommend the following:

Keep it simple, know where your data is being backup, when and what is being excluded.
Use the same hardware. I use the same drives for data and backups. Keep things simple to manage.
Think of the end in mind. If you had to perform a complete restore of all your data, think of what will you need, or wish you did, then work backwards.

Regardless of your methodology of backing up, at least backup. You will not believe how may times friends and family have called me in my life in panic because their computer crashed and they lost all their data. They hope for a miracle that somehow it can be recovered. Sometimes it works, a lot of the time it does not.

There is a lot of free stuff out there if you search on Google as well.

I hope this helps.

Data Security Part I

If you are ever going to sell your computer, replace or upgrade a hard drive, then I HIGHLY recommend that you wipe the old drive first.

Throwing your data in the trash can and emptying it is not enough. All that does is tell the Operating System that there are free blocks that it could write too. However, unless those blocks are written over, chances are the data could be retrieved using over the counter recovery software.

There is no need to purchase any third party application to sanitize your drive, Apple has this built in. It is the Secure Erase feature found in Disk Utility.

Secure Erase has several options, for the most part, the Zero Out feature will be sufficient. The way the product works is that it writes random I/O 0’s & 1’s across the entire drive. The more passes, the more guaranteed that your data is wiped and the longer it will take.

You can get to it by opening up Disk Utility, highlight your disk on the left, select Erase, then Security Options at the Bottom.