Abstract:RAID controller is a hardware device incharge of managing physical drives in a system and presenting them to the computer as logical units. It almost always implements hardware RAID, thus it is sometimes referred to as RAID controller.
The building of RAID 0 and RAID 1 can be set up either via software or hardware. Some operating systems allow you to setup RAID in the software itself. A better option is to have a hardware to control the RAID functions.Hereby guild to Linux.
RAID controller chips are often imbedded in the motherboard.
Hardware RAID You need to ensure that the RAID controller card is designed for the type of hard disks you are using. A RAID controller card designed for use with IDE hard disks will not take SCSI hard disks. A controller designed to provide just RAID 0 functions will not allow you to set up a fault tolerant array.
The big names in the RAID controller business are Adaptec, Highpoint, Intel and Promise. Highpoint and Promise supply most of the RAID chips that are imbedded in both single CPU and dual processor motherboards. They also make the RAID controller cards which are sold on their own. Intel uses it's RAID controller chips in motherboards they produce, Adaptec is mainly known for it's SCSI based products including SCSI cards and SCSI RAID controller cards. Many of the manufacturers also build specialist RAID controller cards for use in "non-standard" situations, eg low profile RAID controller cards for use in restricted spaces like 2 U server cases etc. You can even get RAID for use with newer technologies like SATA. Companies like 3Ware manufacture SATA RAID controller cards.
Tuesday, December 23, 2008
Brief Introduction to RAID Controllers and Cards
Thursday, December 18, 2008
Dynamic Partition Recovery
Dynamic Partitioning is the preferred disk partitioning scheme now a day. This method contains the features that basic partitioning doesn't have. These features including support of volumes spanning, and multipartitioned volumes. In dynamic partitioning, you can resize the volume partitioning without formatting it.
Dynamic partitioning is a hard drive management system used on the Microsoft Windows operating system. It was first introduced with Windows 2000. There are five different types of dynamic disks such as: Simple volume, spanned volume, stripped volume, and mirrored volume and RAID 5 volume.
The LDM or Logical Disk Manager is the subsystem of Windows operating system that manages the dynamic disks. It uses the information stored in the LDM database that located on every partition of the dynamic disk. It is very reliable and easy to use method.
Though it is very reliable and most widely used partitioning method in windows, but sometimes it also can create problems. When your try to reinstall the operating system, you may get following error message:
"Windows XP cannot recognize the partition you selected.
Setup cannot install Windows XP on this partition. However, you can go back to the previous screen, delete the partition. And then select the resulting unpartitioned space.
Setup will then create a new partition on which you can install Windows XP"
This error message occurs because the windows operating system can't always install to the dynamic disk partition. Windows can be installed only the dynamic partition that is the system or boot partition of dynamic volume. This problem occurs only if the MBR entry of the partition is not present for the simple dynamic partition.
To fix this issue, you need to delete the existing primary partition. When you delete the partition, it will be reverted in the basic partition. In this process your windows operating system will generate the following warning:
The partition you attempted to delete is on a dynamic disk. Deletion of this partition will make all other partitions on this disk unusable.
But you have only one option that is partition deletion. Partition deletion is not safe as it will delete all the data stored on the partition and will lead to data loss. In this case, if the partition contains important information then you need to recover the lost data.
Linux Hard Disk Partitions Vs Windows Partitions
Windows Hard Disk Partitions and Drive Letters
Partitions on Windows hard disks are referred to with drive letters.
A Windows hard disk can have more than one partition on it.
Windows refers to Primary partitions and Logical partitions (that are in an Extended partition) with drive letters.
Windows refers to Logical partitions as "Logical drives".
The first partition on the first Windows hard is assigned C: and the next partition, on the same hard disk - or on a different hard disk is D:, and so on.
So, a single Windows hard disk can have multiple drive letters referring to partitions on it, such as C: (for the first partition) and D: (for the second partition).
On a Windows system with a single hard disk and a single partition on the disk, the partition is referred to as C: and then drive D: is typically a CD or DVD drive.
If the Windows hard disk has two partitions, these will usually have the drive letters of C: and D: and then drive E: will usually be a CD or DVD drive.
Linux Hard Disk Partitions Don't Use Drive Letters - They Use Device Names
Linux does not use drive letters to refer to any partitions on a its hard disk.
Linux uses a naming convention (a.k.a. naming scheme) of xxyn to refer to partitions on hard disks.
This naming convention provides much more information than simply using a drive letter. It indicates the drive type, drive position and partition number.
The xx part of the xxyn naming convention is used to specify the hard disk type. In place of xx, the letters hd are used for an IDE hard disk or CD-ROM drive, sd for SCSI, ed for ESDI and xd for an XT hard disk.
For the y part of xxyn, a letter is used for the "position" of the drive. The letter a is for the first drive, b for the second and so on.
For the n part of xxyn, a number is used to represent the partition on the drive.
The numbers 1 through 4 are used for Primary and Extended partitions. Logical partitions can only be created in an Extended partition and a hard disk can only have one Extended partition. The first Logical drive (partition) that is located in an Extended partition is always 5, even if the Extended partition in which it is created does not have the number 4.
The first Primary partition on the first IDE hard disk is referred to as hda1.
So, on a Linux system with a "standard" IDE drive, the first partition is referred to as hda1 and the second partition on the same drive is hda2. The first partition on the second IDE drive is hdb1.
If a Linux system has a SCSI drive, then the first partition on the drive is referred to as sda1 and the second partition on the same drive is sda2. The first partition on the second SCSI drive is sdb1.
If Windows is installed on the first partition of the first hard disk in a system, then Linux still refers to this partition as hda1 (rather than drive C:).
If there is a second partition on the first IDE hard disk, it is referred to as hda2, the third is hda3 and so on.
The Linux concepts regarding partitions covered here apply to: SUSE, Debian, Red Hat, Fedora, Ubuntu, Slackware, openSUSE - and ALL other Linux distributions.
Wednesday, December 17, 2008
How to setup dual boot systems Windows Vista and Linux
The Window Vista users often use multiple partitions on their hard drive, they may want to shrink or extend one of them to meet with installing multi-systems, such as Fedora 10 or Linux,They have to shrink Windows partition down to a separate partition and use the new volume to install Fedora 10 or Linux.
Before we go into the how to on this it is best to discuss what dual booting is and how it is possible. I will mention that the most important issue with setting up a dual booting machine is that Windows MUST be installed first. Because the Windows boot manager is a very single-minded boot manager, it will not recognize any other operating system. To that end, the Linux bootloader must be used.
Now dual booting is exactly as you would expect: A single machine with multiple, working operating systems installed. Upon boot of the machine the Linux boot loader (typically Grub) allows you to select which operating system to boot. This set up is very nice for those wanting to make the transition to Linux or want to use Linux but have Windows to play games on.
Getting Vista Ready
Vista did some things right. One such thing is hard drive partitioning. With Vista you are able to resize a parition, on the fly, without damaging data. Microsoft hid this tool a bit, so you have to know where it is. To open up the Computer Management tool click on the start menu and then right click the Computer entry.
Click on the Manage entry from this new menu to open up the Computer Management tool.
Now it’s time to click on the Disk Management entry. Once you click on that you will see your machine’s hard drive in all its partition’d glory.
There are two parititions on this drive. The larger partition (141.61 GB) is the partition to resize. Right click on that parition to open up a new menu. From this new menu select the “Shrink” entry.
Partition managing menu
Once you select Shrink a new window will appear asking you how much to shrink the drive.
Shrink window
The amount of space to shrink will be the partition your Linux installation is on, so make sure you create enough space.
Once you click the Shrink button your machine will go to work resizing your partition. Once the partition has been resized there will be unallocated space on your drive.
In the image above I only resized the parition a small amount. You will need to create a much larger portion of unallocated space to install Linux.
Once the partition has been resized, it’s time to load Linux.
Installing Linux
Since there are numerous distributions I will only touch on the key aspects you need to watch for. Most likely you will be installing from a LiveCD so boot the LiveCD up. Once the LiveCD has finished booting click on the Install icon to begin the installation process. The first section you need to pay close attention to is the partitioning of the hard drive. What you need to do is make sure the installation uses the free space on the drive. You most likely will have to select the Manual partitioning, but don’t let that scare you. Once you select Manual you will have options to select. There should be the equivalent of using only the free space on your hard drive. Do NOT select anything remotely equivalent to Use Entire Disk. If you make this selection your Windows installation will be erased.
Once the installation partitions the drive it will install all the files it needs. Upon completion of the system installation it will be time to install the boot loader. Just accept the defaults because the Linux boot loader must be the first thing to load on the machine.
Once the boot loader is installed it’s time to reboot. You will notice when you boot (again the exact wording and look of this will depend upon the distribution chosen) there will be a few boot entries. The default entry will be the Linux operating system. If you do nothing within 10 seconds Linux will boot. You can use your arrow keys to select the Windows choice and hit enter to boot into Windows.
Thursday, December 11, 2008
A small hard disk tool: HD tune
HD Tune is a small easy-to-use hard disk utility, has the primary function of transferring rate testing, health status testing, and the temperature detection scanning the time of disk access, CPU occupancy rate. In addition, HD tune can detect the hard drive firmware version, serial number, capacity, the size of the cache, as well as the current Ultra DMA mode. While these features are also found in other software, this valuable software is to integrated all of these functions in one product, but also very compact, fast and more importantly. HD Tune is free software.
HD Tune is a hard disk utility which has the following functions:
Benchmark: measures the raw performance
Transfer Rate
Access Time
CPU Usage
Burst Rate
Hard Disk information which includes partition information, supported features, firmware version, serial number, disk capacity, buffer size, transfer mode
Hard Disk Health
S.M.A.R.T. Information (Self-Monitoring Analysis and Reporting Technology)
Power On Time
Error scan
Temperature display
Copy text to clipboard
Copy screenshot to clipboard
There are 2 editions, one HD tune, the other HD Tune Pro.
Supported operating systems: Windows 2000, Windows XP, Windows 2003 Server, Windows Vista
More about HD tune: offical site
