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Software RAID

Suite Description

The Software RAID suite tests the RAID (Redundant Array of Independent Disks) features on Linux distributions. It includes partitioning the RAID system to install Linux and testing the basic functions that RAID provides on different RAID levels.

Execution Frequency

If the distro supports software RAID, this suite should be executed on one hot-swap RAID system for each beta release during the beta cycle. Testing without hot-swap disks is possible, but failure simulation is more difficult.

Execution Dependencies

This suite has the following dependencies:

Suite Overview

This suite contains the following cases:

No.   Case Name   Blocking
Case
  Estimated
Execution
  Abandon
After
1   RAID level 1 (mirror) installation   yes   30 min   2 hrs
2   RAID level 1 function test   no   20 min   60 min
3   RAID level 0 (striping) installation   yes   30 min   2 hrs
4   RAID level 0 function test   no   10 min   30 min
5   RAID level 5 (striping + redundancy) installation   yes   30 min   2 hrs
6   RAID level 5 function test   no   20 min   60 min

Revision History

Version   Effective Date   Author/Editor   Summary of Changes
1.1   2001-12-1   Airong Zhang   Added level 0 and level 5 tests
1.0   2001-10-15   Airong Zhang   Original suite



RAID Level 1 (Mirror) Installation

A RAID system has more than one hard disk and each disk must be partitioned properly in order for the array to function correctly.

Each of the test disks must have the same partitioning scheme, which must then be fashioned into a software array. If a /boot partition is required by the distro, place it on the first SCSI disk and use two other disks for the RAID array.

The RAID nomenclature may vary from one distro to another. This partitioning case must be completed successfully prior to attempting the RAID function test.

Environment Prerequisites

Preferred architecture: server system with multiple removable disks
System installed? no
Network configured? n/a
Interface: n/a
Logged in as: n/a

Steps

1
Purpose Install the operating system with software RAID support.
Commands 1) Boot off the CD.
2) Enter the graphical installation sequence.
3) Follow the prompts until you reach partitioning.
4) Select the manually partition option. The tool varies from distro to distro.
Expected Results You should be at a partitioning screen.
 
2
Purpose Partition the system with software RAID.
Commands -- Option 1: /boot is a requirement --
Note: This method requires 3 disks.
1) Create /boot (50 MB) and swap (500 MB) partitions on sda.
2) Create identical unmounted partitions (5000+ MB) of type RAID on sdb and sdc.
3) Create a level 1 RAID array containing the unmounted partitions and mount it as / (root).
 
-- Option 2: no /boot requirement --
Note: This method requires 2 disks.
1) Create identical unmounted partitions (5000+ MB) of type RAID level 1 on sda and sdb.
2) Create identical swap (500 MB) partitions on the same drives.
3) Create a level 1 RAID array containing the unmounted 5000 MB partitions and mount it as / (root).
4) Create another level 1 array containing the unmounted 500 MB partitions as the swap.
Expected Results A new device will be added to the partition table. The name of the device may vary by distro, but it is usually md0.
Comments and Tips Normally, you should only test with two drives in the array. The RAID Level 1 Function test is written for a two-drive array. If you add drives, you will also need to modify the failure simulations to account for the presence of additional drives.
 
3
Purpose Finish the installation.
Commands Follow the prompts to install the operating system. See the Installation test suite if you have questions about installation options.
Expected Results The system should reboot after installation.
Comments and Tips Linux will be installed on md0 rather than sda1.
 

Results

System Attempts Pass Pass
w/Errors
Fail Comments
 
 
         
 
 
         
 
 
         



RAID Level 1 Function Test

RAID level 1 provides redundancy by writing identical data to each member disk of the array, leaving a "mirrored" copy on each disk. If a member drive fails, the remaining drive contains an exact copy of the data.

Level 1 operates with two or more disks that may use parallel access for high data-transfer rates. The tests here include read/write function and simulated drive failure for a two-drive array.

The "main" drive is the one in the first bay (excluding the boot drive, if one was required) at the beginning of testing. The "mirror" drive starts out in the bay below the main drive. You may find it helpful to note which drive is in which bay at each point a drive removal or insertion is made.

Environment Prerequisites

Preferred architecture: server system with multiple removable disks
System installed? as indicated in RAID Level 1 Installation test
Network configured? n/a
Interface: tester preference
Logged in as: user

Steps

Important note: Refer to and comply with the manufacturer's instructions for removing disks.

1
Purpose Verify the size of the root partition.
Commands df -h
Expected Results The "size" column for /dev/md0 should show a value roughly equal to the size of one member disk.
Comments and Tips None
 
2
Purpose Create a new directory and a new file.
Commands 1) cd /home/userid
2) mkdir tmp
3) cd tmp
4) vi testfile
5) Press i and type "This is a test of RAID level 1".
6) Save the file (ESC :wq).
7) ls -l
Expected Results You should see "testfile" in the folder you created.
Comments and Tips  
 
3
Purpose Simulate a failure on the main drive.
Commands 1) su
2) shutdown -h now
3) Power off the system.
4) Pull out the main drive.
5) Power on the system.
Expected Results The system should reboot normally.
Comments and Tips If you had to install with a boot drive (option 1), the main drive will be the second physical drive. In this case, adjust all drive references appropriately.
 
4
Purpose Verify that the newly created file exists on the mirror drive.
Commands 1) cd /home/userid
2) ls -l
3) cat testfile
Expected Results The file "testfile" should be present with the correct contents.
Comments and Tips  
 
5
Purpose Verify that the system can be rebooted with the two drives swapped.
Commands 1) su
2) shutdown -h now
3) Power off the system.
4) Move the mirror drive to the first slot and put the main drive in the second slot.
5) Power on the system.
Expected Results The system should boot normally.
Comments and Tips  
 
6
Purpose Verify that the system can be rebooted with only the main drive.
Commands 1) Log in as root
2) shutdown -h now
3) Power off the system.
4) Pull out the mirror drive.
5) Power on the system to reboot.
Expected Results The system should boot normally.
Comments and Tips  
 
7
Purpose Verify that the system can work correctly with only one drive.
Commands 1) cd /home/userid
2) mkdir tmp2
3) cd tmp2
4) vi testfile2
5) Press i and type "This is another test of RAID level 1".
6) Save the file (ESC :wq).
7) ls -l
8) cat testfile2
Expected Results The file "testfile2" should be present with the correct contents.
Comments and Tips  
 

Results

System Attempts Pass Pass
w/Errors
Fail Comments
 
 
         
 
 
         
 
 
         



RAID Level 0 (Striping) Installation

A RAID system has more than one hard disk and each disk must be partitioned properly in order for the array to function correctly.

The test disks do not need to have the same partitioning scheme for a level 0 array.

The RAID nomenclature may vary from one distro to another. This partitioning case must be completed successfully prior to attempting the RAID function test.

Environment Prerequisites

Preferred architecture: server system with multiple disks
System installed? no
Network configured? n/a
Interface: n/a
Logged in as: n/a

Steps

1
Purpose Install the operating system with software RAID support.
Commands 1) Boot off the CD.
2) Enter the graphical installation sequence.
3) Follow the prompts until you reach partitioning.
4) Select the manually partition option. The tool varies from distro to distro.
Expected Results You should be at a partitioning screen.
 
2
Purpose Partition the system with software RAID.
Commands 1) Create /boot (50 MB) and swap (500 MB) partitions on sda.
2) Create an unmounted partition (1000 MB) of type RAID on sdb.
3) Create an unmounted partition (2500 MB) of type RAID on sdc.
3) Create a level 0 RAID array containing the unmounted partitions and mount it as / (root).
Expected Results A new device will be added to the partition table. The name of the device may vary by distro, but it is usually md0.
Comments and Tips You want to make sure that no single member partition is large enough to hold the entire installation. The array itself, however, must be large enough for the installation.
 
3
Purpose Finish the installation.
Commands Follow the prompts to install the operating system. See the Installation test suite if you have questions about installation options.
Expected Results The system should reboot after installation.
Comments and Tips Linux will be installed on md0 rather than sda1.
 

Results

System Attempts Pass Pass
w/Errors
Fail Comments
 
 
         
 
 
         
 
 
         



RAID Level 0 Function Test

RAID level 0 combines multiple small disks to present a single large disk to the operating system. It does not provide any redundancy. If a member drive fails, the data is lost.

Data written to a level 0 array is broken down into strips and written across the member disks of the array. This allows high I/O performance at low inherent cost but provides no redundancy.

Because there is no redundancy provided by this type of RAID, there are no failure simulations for this test.

Environment Prerequisites

Preferred architecture: server system with multiple disks
System installed? as indicated in RAID Level 0 Installation test
Network configured? n/a
Interface: tester preference
Logged in as: user

Steps

1
Purpose Verify the size of the root partition.
Commands df -h
Expected Results If you used the suggested partitioning scheme, the "size" column for /dev/md0 should show about 3.5 GB. If you used a different scheme, the md0 entry should be equal to the sum of all member partitions.
Comments and Tips None
 
2
Purpose Create a new directory and a new file.
Commands 1) cd /home/userid
2) mkdir tmp
3) cd tmp
4) vi testfile
5) Press i and type "This is a test of RAID level 0".
6) Save the file (ESC :wq).
7) ls -l
Expected Results You should see "testfile" in the folder you created.
Comments and Tips  
 

Results

System Attempts Pass Pass
w/Errors
Fail Comments
 
 
         
 
 
         
 
 
         



RAID Level 5 (Striping + Redundancy) Installation

A RAID system has more than one hard disk and each disk must be partitioned properly in order for the array to function correctly.

Each of the test disks must have the same partitioning scheme, which must then be fashioned into a software array. If a /boot partition is required by the distro, place it on the first SCSI disk and use three or more other disks for the RAID array.

The RAID nomenclature may vary from one distro to another. This partitioning case must be completed successfully prior to attempting the RAID function test.

Environment Prerequisites

Preferred architecture: Server system with at least three removable disks
System installed? no
Network configured? n/a
Interface: n/a
Logged in as: n/a

Steps

1
Purpose Install the operating system with software RAID support.
Commands 1) Boot off the CD.
2) Enter the graphical installation sequence.
3) Follow the prompts until you reach partitioning.
4) Select the manually partition option. The tool varies from distro to distro.
Expected Results You should be at a partitioning screen.
 
2
Purpose Partition the system with software RAID.
Commands -- Option 1: /boot is a requirement --
Note: This method requires 4 disks.
1) Create /boot (50 MB) and swap (500 MB) partitions on sda.
2) Create identical unmounted partitions (3000+ MB) of type RAID on sdb, sdc and sdd.
3) Create a level 5 RAID array containing the unmounted partitions and mount it as / (root).
 
-- Option 2: no /boot requirement --
Note: This method requires 3 disks.
1) Create identical unmounted partitions (3000+ MB) of type RAID on sda, sdb and sdc.
2) Create identical swap (500 MB) partitions on the same drives.
3) Create a level 5 RAID array containing the unmounted 3000 MB partitions and mount it as / (root).
4) Create another level 5 array containing the unmounted 500 MB partitions as the swap.
Expected Results A new device will be added to the partition table. The name of the device may vary by distro, but it is usually md0.
Comments and Tips Normally, you should only test with three drives in the array. The RAID Level 5 Function test is written for a three-drive array. If you add drives, you will also need to modify the failure simulations to account for the presence of additional drives.
 
3
Purpose Finish the installation.
Commands Follow the prompts to install the operating system. See the Installation test suite if you have questions about installation options.
Expected Results The system should reboot after installation.
Comments and Tips Linux will be installed on md0 rather than sda1.
 

Results

System Attempts Pass Pass
w/Errors
Fail Comments
 
 
         
 
 
         
 
 
         



RAID Level 5 Function Test

A level 5 RAID array consists of n disks combined together to present the operating system with a single logical disk with the storage capacity of n-1 times the capacity of a single physical disk. The last disk provides redundancy such that if any single member disk fails, data is preserved.

Environment Prerequisites

Preferred architecture: server system with at lease three removable disks
System installed? as indicated in RAID Level 5 Installation test
Network configured? n/a
Interface: tester preference
Logged in as: user

Steps

1
Purpose Verify the size of the root partition.
Commands df -h
Expected Results If you used three 3000 MB partitions, the "size" column for /dev/md0 should show about 6 GB. If you used a different size partition or more drives, the md0 entry should be equal to (n-1) * partition size.
Comments and Tips None
 
2
Purpose Create a new directory and a new file.
Commands 1) cd /home/userid
2) mkdir tmp
3) cd tmp
4) vi testfile
5) Press i and type "This is a test of RAID level 5".
6) Save the file (ESC :wq).
7) ls -l
Expected Results You should see "testfile" in the folder you created.
Comments and Tips  
 
3
Purpose Simulate a disk failure.
Commands 1) su
2) shutdown -h now
3) Power off the system.
4) Pull out a disk.
Expected Results The system should reboot normally.
Comments and Tips If you had to install with a boot drive (option 1), be sure not to remove the first drive.
 
4
Purpose Verify that the system still boots.
Commands Power on the system.
Expected Results The system should boot normally.
Comments and Tips  
 
5
Purpose Verify that the test file is still present.
Commands 1) cd /home/userid
2) ls -l
3) cat testfile
Expected Results The file "testfile" should be present with the correct contents.
Comments and Tips  
 

Results

System Attempts Pass Pass
w/Errors
Fail Comments
 
 
         
 
 
         
 
 
         

 


 

Legal Information

The information included in this test instruction document is provided AS IS without warranty of any kind. IBM EXPRESSLY DISCLAIMS ANY WARRANTIES, EXPRESS OR IMPLIED, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. IBM does not warrant any results or performance measurements obtained. Any information concerning IBM products was written for IBM products offered in the U.S.A. IBM may not offer the products, services or features discussed in this document in other countries, and the information is subject to change without notice. The information in this document relating to Linux is provided as a convenience to Linux users, and IBM makes no warranty or representation, express or implied, with respect to the accuracy and completeness of the information, and assumes no responsibility for any errors, which may appear in the document. Any performance or test data contained herein was determined in a controlled test environment. Therefore, the results obtained in other operating environments may vary. No license, express or implied, to any intellectual property is granted by this document. IBM may make improvements and/or changes in product(s) and/or programs described in this publication at any time without notice.

Linux is a trademark of Linus Torvalds.

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