IOPS (I/O’s per Second,
or iostat "tps")

Data Transfer Rate
(MB/sec)

Minimum Number of Disk Drives to Support Workload

Random I/O (10k RPM)

125

0.5

n = (%R + f (%W))(tps)/125

Random I/O (15k RPM)

150

0.5+

n = (%R + f (%W))(tps)/150

Sequential I/O

2000

50

n = (MB/sec)/50

Where:
%R = the percentage of disk I/O’s that are reads.
%W= the percentage of disk I/O’s that are writes.
f = 1 for ordinary disks, 2 for mirrored disks, 4 for Raid 5 disks.
Assumes data is distributed evenly across all disk drives.

Using the above formula, here’s the minimum number of disks required to support a random I/O workload, at 1000 IOPS,  80% read, 20% write on 10K RPM disk drives.

Ordinary disks:  (0.8 + 1*0.2)(1000 IOPS)/(125 IOPS/disk)  = 8
Mirrored disks:  (0.8 + 2*0.2)(1000 IOPS)/(125 IOPS/disk)  = 10
Raid 5 disks:      (0.8 + 4*0.2)(1000 IOPS)/(125 IOPS/disk) =  13

Full Article Here

To start Server Administrator, perform the following steps:

1. Click the Start button and point to Settings® Control Panel® Administrative Tools® Services.
   The Services window appears.
2. Right-click the Secure Port Server icon.
3. Click Start.

To stop Server Administrator, perform the following steps:

1. Click the Start button and point to Settings® Control Panel® Administrative Tools® Services.              The Services window appears.
2. Right-click the Secure Port Server icon.
3. Click Stop.

I will say this: Do not give in and use all the tricks all the time if you are just starting with Linux. It’s always best (in my opinion) to learn the ropes and background to everything before using the GUI or any related tricks. I believe this is true with almost any learning process – technology-based or not.

Command Line File Name Completion

Tired of typing the whole path to a single command? Some commands can be very large and cumbersome. Try “tabbing it out”.

Try for example: where<tab>

The above should return whereis. If you have more than one binary in your path that contains the word where you may not get a result. In this case hit tab again and you’ll be presented with all options.

Print Working Directory (pwd)

The pwd command is useful to tell you what directory you are currently in. Depending on your shell configuration, you will be presented with your full working directory in the title of your shell program. For instance, I use putty and it always shows my Current Working Directory (CWD).

 
Command History

Forget what the last few commands you completed were? Want to diagnose a system and you have no idea what the person before you executed? Try the “history” command in Linux.

Type “history”. This provides a list of all recently entered commands and can be very large. If you type “history 10” it works much like the tail command and shows the last 10 commands in history.

Type “history –c” to clear your command history.

Output Redirection

Tons of information from the command you just executed? Redirect the output to a file or another program.

Examples:

# echo “foo” > bar (this example will echo the text “foo” to the file called “bar”)

# echo “foo2” >> bar (this example will echo the text “foo2” to the end of the file “bar”)

# wc –l < bar (this example will do a line count on the file bar)

Typically commands read, by default from STDIN. For instance I could also run wc like this:

# wc -l bar

I would still obtain the same results as explicitly telling the CLI to use STDIN (<).

Aliases

Using aliases is another way to make entering common commands easier. Think of an alias as a simple shortcut to a longer command. Let’s say you want to remove a directory and you’re tired of always typing “rm –rf <directory”. You can make an alias by typing “alias rmdir=’rm –rf’. Now you can type “rmdir <directory>” on the CLI and achieve the same result.

Symbolic Links

A symbolic link is simply a pointer to another file/directory. To make a shortcut to a program shorter or as a link inside your home directory use a command like this:

# ln –s /usr/local/program/bin/program ~/program

- or to link an entire directory -

# ln –s /usr/local/program ~/program

Symbolic links appear when performing an ls –lt like this:

apropos Search Whatis Database

Ever wanted to find a command but never knew the name? Do you know what the command does or a description but can’t put your finger on it? Use the command apropos to search the whatis database.

Just type apropos “string to search for”

Whereis – Find a binary or man page

Ever needed to find the location of a binary easily? Try “whereis”. Simply type whereis “binary” and you will be presented with a location to the binary and/or manpage for the given binary.

There are a ton of other shortcuts I am missing but this is just a small list. Have a great day!

Information    12/15/2008 8:07:49 AM    Locking partition C:…
Error    12/15/2008 8:10:00 AM    Operation with partition "2-0" was terminated.
Details:
Run list corrupted (0×7001C)
    Tag = 0×89D94B01B483E221

To rectify this issue just run a "CHKDSK C: /R" which should clean up a few NTFS attributes. This usually will happen if you hard-cycle your system for some reason.

Directly from Seagate’s manual:

Serial ATA drives are designed for easy installation. It is usually not necessary to set any jumpers on the drive
for proper operation; however, if you connect the drive and receive a “drive not detected” error, your SATAequipped
motherboard or host adapter may use a chipset that does not support SATA speed autonegotiation. If
you have a motherboard or host adapter that does not support autonegotiation:
•Install a jumper as shown in Figure 3 below to limit the data transfer rate to 1.5 Gbits per second (and leave the drive connected to the SATA-equipped motherboard or host adapter that doesn’t support autonegotiation) or
•Install a SATA host adapter that supports autonegotiation, leave the drive jumper block set to “Normal operation” (see Figure 3 below), and connect the drive to that adapter. This option has the benefit of not limiting the drive to a 1.5 Gbits/sec transfer rate.

The only issue is that the jumper comes pre-installed on these drives in particular.

Good luck and happy hard disking!

If there was an MTV on demand here is what the selections would look like:

1. Whining teenage girls talking about how bad their life sucks and how they want to be popular.

2. Whining teenage girls talking about how much of a “slut” and “whore” members of their cohorts are.

3. Real-world scenarios that they “happened” to catch on tape with no planned scenarios or scenes.

4. Look at how much of a spoiled brat I am on my sixteenth birthday. I’m so rich and you’re not.

5. Find out who’s sleeping with who on “The Hills”.

I absolutely despise “Reality” tv as played on MTV. What has the world come to? When my better half watches MTV at home I promptly switch the channel to TRU TV. At least that shows some real TV. People getting shot, people going to jail and getting DUI’s is far more real than MTV.

Thank you MTV for turning the brains of millions who watch your nonsensical crap into mush. I’d rather slam my head into a brick wall repeatedly because its 100% more real than watching your poor excuse for a television show.

If someone out there could make a device that stabs people who watch MTV in the face over the Internet we would be millionaires. Unfortunately, people will keep watching MTV and we’ll never win.

In the words of Dire Straits: “I want my MTV”

1. RAID is usually susceptible to double-disk RAID faults. While this may not sound like a normal or even conceivable possibility it is a very real issue that I have personally experienced. RAID-6 offers some higher levels of protection to this problem. Most new 9600 series 3Ware controllers (and most newer controllers) offer RAID-6 capabilities. Choose a RAID-6 able card and, if possible, always run a BBU (Battery Backup Unit).
2. RAID will never protect against file corruption or viruses. 
3. RAID can’t protect against human error. We’re all human, we all make mistakes. If you just hit the delete key on an entire directory of your company’s data then you can probably hit the delete key on your job as well. This is why backups, along with RAID, is the best data integrity solution.
4. RAID will only protect you if you are proactive. Some lower quality RAID controllers do not send email alerts and do not properly alert you of an issue. These controllers require special attention. The more user interaction is needed the less likely you will notice a fault. Having a hot spare or spare disks available for swapping is always a good idea.
5. RAID will not facilitate off-site and disaster recovery scenarios. There are some utilities out there that provide block-level replication.

In summary, the best data integrity plan is to use RAID to supplement your plan. Don’t rely on RAID as your sole backup/data security mechanism. I personally recommend using RAID-6 with a block-level backup of all data to an off-site location. Using software like R1Soft’s CDP will allow for full block-level backups and file-level and bare-metal restores. Remember to always double check your data integrity plan and never be satisfied with your solution! I personally hate loosing data. With drives as cheap as they are today, why aren’t you backing up offsite?

1. top

   
   

   Yes, that’s right, good ol’ fashioned “top”. If you haven’t already used the top command then you may not have been using Linux that much. Top provides a real-time look at processor time, processes that are using high amounts of memory/CPU and also an overview of physical and swap memory.  A preview of top can be seen to the right. Press “1” to show all CPU’s available (if running multiple-core processors or HT-enabled processors).

2. htop
   

   There are also other top variants out there which can provide more information in the same “top-like” format. Enter htop. Htop has been around for quite some time and has, as far as I know, gone generally unknown around the Linux world. htop provides colorful (who doesn’t like colors?) views of the system state and shows tree views for processes that provide even more detail. A screenshot of the htop interface can be seen on the right. Obtain more information about htop here.

3. iostat
   

   Got disk performance issues? Find out with iostat! iostat is used for monitoring speed, ops/sec and cpu time spent waiting on input/output devices to respond. This command is quite useful when attempting to see what is causing your load averages to spike. If your system has high i/o wait times you may consider purchasing faster disks or tuning the performance of your application to be less disk-intensive. Performance tuning, for instance, of a MySQL database can greatly decrease the amount of disk i/o needed. Adding indexes and re-constructing queries can speed up MySQL systems that have high i/o wait times. Of course, you can always throw hardware at the issue as well. For more information on iostat see this article.

4. vmstat
    

   Direct from the vmstat man page: “vmstat reports information about processes, memory, paging, block IO, traps, and cpu activity.” The data shown in vmstat is the average since last reboot.
    
   Direct from man page:

   Procs
          r: The number of processes waiting for run time.
          b: The number of processes in uninterruptible sleep.

   Memory
          swpd: the amount of virtual memory used.
          free: the amount of idle memory.
          buff: the amount of memory used as buffers.
          cache: the amount of memory used as cache.
          inact: the amount of inactive memory. (-a option)
          active: the amount of active memory. (-a option)

   Swap
          si: Amount of memory swapped in from disk (/s).
          so: Amount of memory swapped to disk (/s).

   IO
          bi: Blocks received from a block device (blocks/s).
          bo: Blocks sent to a block device (blocks/s).

   System
          in: The number of interrupts per second, including the clock.
          cs: The number of context switches per second.

   CPU
          These are percentages of total CPU time.
          us: Time spent running non-kernel code. (user time, including nice time)
          sy: Time spent running kernel code. (system time)
          id: Time spent idle. Prior to Linux 2.5.41, this includes IO-wait time.
          wa: Time spent waiting for IO. Prior to Linux 2.5.41, shown as zero.

5. ps

   Although the ps “process list” command does not show real-time updates it can provide useful information as to why your system may be slow. I typically use the “aux” options that shows enough detail but also adding “ww” to the end of “aux” yeilds good results for long commands. Run “ps aux” and look for multiple processes. This is good for troubleshooting if a process like Apache or Exim have spawned many children and caused the system to slow. Use the “e” flag to show children in a tree format.

    

IBM brings a new line of processors and machines to the market with unreal memory capacities.