RAID Controller Utility

RAID Controller Utility from IBM
On RAID models, this utility is the only one that can discover and configure the attached SCSI devices. 

   This utility comes on a bootable diskette which is shipped with every RAID Server.  Also, it can be rebuilt if necessary with the Diskette Factory option of ServerGuide. 

   The IBM RAID utility allows you to configure disk arrays as well as view the status of the arrays already defined.  It provides a graphical display of the defined arrays and provides diagnostic information to assist you if  a hard disk within the array malfunctions. 

  The common configuration tasks described here are: 
   View configuration 
   Low-level format of the disks 
   Change RAID Parameters  
   Defining a hot-spare drive 
   Creating a disk array 
   Defining logical drives 
   Set Write Policy  
   Initialize Array  
   Backup/restore the configuration 

   After booting with the RAID Controller program diskette, if more than one RAID adapter is installed, it will prompt you to select which adapter you want to work with (see Figure 54).  Otherwise, a screen like the one in Figure 55 will appear. 



Figure 54. RAID Configuration Program - Adapter Selection

                      IBM RAID Controller Configuration Ver 2.12
                       _______________________________ 
                       |        Select Adapter        | 
                       |______________________________| 
                       | 1. Help                      | 
                       | 2. RAID Controller in slot 1 | 
                       | 3. RAID Controller in slot 2 | 
                       | 4. Exit                      | 
                       |______________________________| 



   Use the arrow keys to select the adapter you want to configure and press  Enter. 

   A screen like the one in Figure 55 will appear. 


                  IBM RAID Controller Configuration Ver 2.12

                               Adapter in Slot 1 
                          _______________________________ 
                         |           Main Menu           | 
                         |_______________________________| 
                         |1. Help                        | 
                         |2. View configuration          | 
                         |3. Create/delete Array         | 
                         |4. Initialize/synchronize array| 
                         |5. Rebuild device              | 
                         |6. Advanced functions          |
                         |7. Drive information           | 
                         |8. Exit                        | 
                         |_______________________________|



Drive Information
During this first step, we will verify that all the installed units are recognized and available for future use.  Select Drive Information on the main menu. The following screen appears: 



                       IBM RAID Controller Configuration Ver 2.12 
                                  Adapter in Slot 1

      ____________________________         ___________    ___________
     |     Drive Information      |       | _________ |  | _________ |
     |____________________________|       ||Ch      1||  ||Ch      2||
                                          | _Bay      |  | _Bay      |
                                          || Array __ |  || Array __ |
                                          |   _____   |  |   _____   |
                                          |1 |     |  |  |1 |     |  |
                                          |   _____   |  |   _____   |
                                          |2 |     |  |  |2 |     |  |
                                          |   _____   |  |   _____   |
                                          |3 | RDY |  |  |3 |     |  |
                                          |   _____   |  |   _____   |
                                          |4 | RDY |  |  |4 |     |  |
 _______________________________________  |   _____   |  |   _____   |
| Drive ID        IBM DFHSS2W     1717  | |5 | RDY    |  |5 |     |  |
| Drive Capacity  2150MB                | |   _____   |  |   _____   |
| Soft Error      0                     | |6 | RDY |  |  |6 |     |  |
| Hard Error      0                     | |   _____   |  |   _____   |
| Misc Error      0                     | |7 | CDR |  |  |7 |     |  |
|_______________________________| |________| |_________|



   Figure 56. RAID Configuration Program - Drive Information 

   The columns on the right show any devices attached to each channel on the adapter. The box on the left shows information about a specific device. The unit whose information is displayed is highlighted on the right. 

   Use the up and down arrow keys to display the information for other devices. 

   The RAID Utility shows device type and/or status for each device which it recognizes.  The devices may take on several states which you may encounter when running the Utility. 
    Here is a list of indicators used along with a description of each:

°   CDR = A CD-ROM device.
°   DDD = Defunct DASD device.
°   FMT = DASD being formatted.
°   HSP =  DASD defined as a hot-spare Drive.
°   OFL =  DASD used to rebuild a defunct drive.  Intermediate state between DDD and ONL.
°   ONL = DASD which has been assigned to an Array.
°  RDY =  DASD ready to use but not assigned to an array or defined as hot-spare drive.
°   TAP = A Tape Drive.
°   UFM = Unformatted DASD. Requires an LLF before it can be used. 



Formatting the Disks
   If your DASD devices appear as UNF or if you have experienced some problems with them, you can low-level format the disks. If your disks appear as RDY, and you don't want to reformat, then you can skip over this section. 

   To format a device: 
   1.  From the main menu select Advanced Functions.  The following menu appears: 



        IBM RAID Controller Configuration Ver 2.12
                    Adapter in Slot 1
            _______________________________ 
           |      Advanced Functions       |
           |_______________________________|
           |1. Help                        |
           |2. Backup config. to diskette  | 
           |3. Restore config. to diskette |
           |4. Change write policy         |
           |5. Format drive                | 
           |6. Change RAID parameters      |
           |7. Exit                        |
           |_______________________________|


   Figure 57. RAID Configuration Program - Advanced Functions Menu 

   2.  Select Format drive. 
   3.  With the spacebar, select devices to format. They appear as FMT. 
   4.  Press Enter to format the selected drives. 

Notes 
   All the desired devices may be selected and formatted together to reduce the time necessary for formatting. The operation can be time consuming. It takes approximately 20 minutes to format six 2GB disks attached to the same adapter.



                 IBM RAID Controller Configuration Ver 2.12
                           Adapter in Slot 1 

         _______________________________   ___________    ___________ 
        |      Advanced Functions       | | _________ |  | _________ |
        |_______________________________| ||Ch      1||  ||Ch      2||
        |1. Help                        | | _Bay      |  | _Bay      |
        |2. Backup config. to diskette  | || Array __ |  || Array __ |
        |3. Restore config. to diskette | |   _____   |  |   _____   |
        |4. Change write policy         | |1 |     |  |  |1 |     |  |
        |5. Format drive                | |   _____   |  |   _____   |
        |6. Change RAID parameters      | |2 |     |  |  |2 |     |  |
        |7. Exit                        | |   _____   |  |   _____   |
        |_______________________________| |3 | FMT |  |  |3 |     |  |
                                          |   _____   |  |   _____   |
                                          |4 | FMT |  |  |4 |     |  |
                                          |   _____   |  |   _____   |
                                          |5 | FMT |  |  |5 |     |  |
                                          |   _____   |  |   _____   |
                                          |6 | FMT    |  |6 |     |  |
                                          |   _____   |  |   _____   |
                                          |7 |     |  |  |7 |     |  |
                                          |___________|  |___________|



   Figure 58. RAID Configuration Program - DASD Formatting 

Change RAID Parameters
   The panel for changing RAID parameters looks like Figure 59. 



             IBM RAID Controller Configuration Ver 2.12
                            Adapter in Slot 1

          _______________________________    ___________    ___________ 
         |      Advanced Functions       |  | _________ |  | _________ |
         |_______________________________|  ||Ch      1||  ||Ch      2||
         |1. Help                        |  | _Bay      |  | _Bay      |
         |2. Backup Config. to Diskette  |  || Array __ |  || Array __ |
         |3. Restore Config. to Diskette |  |   _____   |  |   _____   |
         |4. Change Write Policy         |  |1 |     |  |  |1 |     |  |
         |5. Format Drive                |  |   _____   |  |   _____   |
         |6. Change RAID parameters      |  |2 |     |  |  |2 |     |  |
         |7. Exit                        |  |   _____   |  |   _____   |
         |_______________________________|  |3 | RDY |  |  |3 |     |  |
________   _________   _________   ______   |   _____   |  |   _____   |
|Stripe | |Rebuild  | |Parity   | |Read  |  |4 | RDY |  |  |4 |     |  |
|Unit   | |Priority | |Placement| |Ahead |  |    _____  |  |   _____   |
|Size   | |  High   | |   RA    | | On   |  |5 | RDY |  |  |5 |     |  |
|_______| |_________| |_________| |______|  |   _____   |  |   _____   |
|   8K  | |1 Equal  | |1  RA    | |1 On  |  |6 | RDY |  |  |6 |     |  |
|  16K  | |2 High   | |2  LS    | |2 Off |  |   _____   |  |   _____   |
|  32K  | |3 Low    | |_________| |______|  |7 |     |  |  |7 |     |  |
|  64K  | |_________|                       |___________|  |___________|
|_______| 


   Figure 59. RAID Configuration Program - Change RAID parameters 

The following fields are configurable: 
Stripe Unit Size: The stripe unit size is the amount of data written on a given disk before writing on the next disk. This parameter should be chosen such that the stripe unit size is close to the size of the system I/O requests. The default is set to 8KB. 
Warning!  Once data is stored in the logical drive, the stripe unit cannot be changed without destroying data in the logical drives. 

Rebuild Priority:  This parameter sets the priority of the execution order of the rebuild I/O requests with respect to the system I/O requests. 
Note: Rebuild priority can be changed without destroying data.
Equal - The rebuild I/O request and system I/O requests get equal priority in the execution order.
High - Rebuild I/O requests get a higher priority than system I/O requests. On a heavily loaded system (with a high rate of system I/O requests), the high-priority rebuild can significantly reduce the disk rebuild time at the expense of degraded handling of I/O requests.
Low - Rebuild I/O requests can execute only if there is no pending system I/O requests. On a moderate to heavily loaded system, low rebuild priority will significantly increase the disk rebuild time and gain higher system performance. (Ed. I'd say that you would only want busmasters in this system to reduce system I/O...)

Parity Placement:  Parity placement defines how parity is placed in the disk array with respect to the data. The following figure shows the differences between Left Symmetric and Right Asymmetric parity placement. 

   AAA, BBB, CCC and so on are the data stripe units; PP1-3 are the corresponding parity. 
         Right Asymmetric (RA)          Left Symmetric (LS) 
         Disk Disk Disk Disk           Disk Disk Disk Disk 
          1    2    3    4              1    2    3    4 
         PP0  AAA  BBB  CCC            AAA  BBB  CCC  PP0 
         DDD  PP1  EEE  FFF            EEE  FFF  PP1  DDD 
         GGG  HHH  PP2  III            III  PP2  GGG  HHH 
         JJJ  KKK  LLL  PP3            PP3  JJJ  KKK  LLL 
   The default value is Right Asymmetric. In some situations, you may want to try Left Symmetric to improve performance. 
   Note: Once a parity placement scheme is chosen and data is stored in the logical drives, it cannot be changed without destroying data in the logical drives. 

 Read-Ahead:  Normally the IBM SCSI-2 Fast/Wide Streaming RAID adapter transfers data from a disk to its local cache in steps of stripe unit size. This provides excellent overall performance when workloads tend to be sequential.  However, if the workload is random and system I/O requests are smaller than stripe unit size, reading ahead to the end of the stripe unit will result in a wasted SCSI bus bandwidth and wasted disk utilization. 
   When Read-Ahead is set to OFF, the size of data transfer from the disk to the local cache is equal to the system I/O request size, and no read-ahead to the end of the stripe unit size is performed. 
 Note:  The Read-Ahead setting can be modified without destroying data in a logical unit. 



Defining a Hot-Spare Disk
After selecting Create/delete array from the main menu of the IBM RAID 
   Configuration program, the following screen appears: 

                 IBM RAID Controller Configuration Ver 2.12
                           Adapter in Slot 1

 ____________________________       ___________    ___________
|      Create/Delete Array   |     | _________ |  | _________ |
|____________________________|     ||Ch      1||  ||Ch      2||
|1. Help                     |     | _Bay      |  | _Bay      |
|2. Define hot-spare drive   |     || Array __ |  || Array __ |
|3. Delete disk array        |     |   _____   |  |   _____   |
|4. Create disk array        |     |1 |     |  |  |1 |     |  |
|5. Define Logical drive     |     |   _____   |  |   _____   |
|6. Format drive             |     |2 |     |  |  |2 |     |  |
|7. Exit                     |     |   _____   |  |   _____   |
|____________________________|     |3 | RDY |  |  |3 |     |  |
                                   |   _____   |  |   _____   |
                                   |4 | RDY |  |  |4 |     |  |
                                   |   _____   |  |   _____   |
                                   |5 | RDY |  |  |5 |     |  |
                                   |   _____   |  |   _____   |
                                   |6 | RDY    |  |6 |     |  |
                                   |   _____   |  |   _____   |
                                   |7 |     |  |  |7 |     |  |
                                   |___________|  |___________|



   Figure 60. RAID Configuration Program - Create/Delete Array Menu 

   1.  Select Define hot-spare drive.  The cursor becomes active in the Bay/Array selection list. 
   2.  Use the up and down arrow keys to select the RDY (ready) drive to be used as a hot-spare and press Enter. The RDY status changes to HSP (hot-spare).  Figure 61 shows an example where a hot-spare disk has been defined. 
   3.  Press Esc to validate. 

   Notes: 
   1.  The hot-spare drive is not associated with any array.  If more than one array is defined, you need only 1 hot-spare drive for all the arrays. 
   2.  If the disks have different sizes, the hot-spare drive must be the largest. 



               IBM RAID Controller Configuration Ver 2.12
                         Adapter in Slot 1 

         ____________________________       ___________    ___________
        |      Create/Delete Array   |     | _________ |  | _________ |
        |____________________________|     ||Ch      1||  ||Ch      2||
        |1. Help                     |     | _Bay      |  | _Bay      |
        |2. Define hot-spare drive   |     || Array __ |  || Array __ |
        |3. Delete disk array        |     |   _____   |  |   _____   |
        |4. Create disk array        |     |1 |     |  |  |1 |     |  |
        |5. Define Logical drive     |     |   _____   |  |   _____   |
        |6. Format drive             |     |2 |     |  |  |2 |     |  |
        |7. Exit                     |     |   _____   |  |   _____   |
        |____________________________|     |3 | HSP |  |  |3 |     |  |
                                           |   _____   |  |   _____   |
                                           |4 | RDY |  |  |4 |     |  |
                                           |   _____   |  |   _____   |
                                           |5 | RDY |  |  |5 |     |  |
                                           |   _____   |  |   _____   |
                                           |6 | RDY    |  |6 |     |  |
                                           |   _____   |  |   _____   |
                                           |7 |     |  |  |7 |     |  |
                                           |___________|  |___________|



Figure 61. RAID Configuration Program - Hot-Spare Disk Definition 



Creating a Disk Array
1.  Select Create/Delete Array from the Main Menu. 
   2.  Select Create Disk Array from the Create/Delete Array menu and press Enter. 
   3.  Using the Enter key, select each drive you want included in the array 
       you are now defining. The devices will be highlighted as they are 
       selected and the status changes from RDY to ONL (online).  Also the 
       array ID, (A for the first one, then B and so on) appears behind the 
       drives that make up the array. 
   4.  Press Esc to validate. 


            IBM RAID Controller Configuration Ver 2.12
                      Adapter in Slot 1 

                                              ___________    ___________ 
                                             | _________ |  | _________ |
                                             ||Ch      1||  ||Ch      2||
                                             | _Bay      |  | _Bay      |
                                             || Array __ |  || Array __ |
                                             |   _____   |  |   _____   |
                                             |1 |     |  |  |1 |     |  |
                                             |   _____   |  |   _____   |
                                             |2 |     |  |  |2 |     |  |
                                             |   _____   |  |   _____   |
                                             |3 | HSP |  |  |3 |     |  |
                                             |   _____   |  |   _____   |
 _______________ ___________________________ |4 | ONL | A|  |4 |     |  |
|Array Arrays   | Log  Size RAID   Date    | |   _____   |  |   _____   |
|ID    Size (MB)| Drv  (MB) Level  Created | |5 | ONL | A|  |5 |     |  |
|_______________|__________________________| |   _____   |  |   _____   |
| A    6450     |                          | |6 | ONL   A|  |6 |     |  |
|               |                          | |   _____   |  |   _____   |
|               |                          | |7 |     |  |  |7 |     |  |
|_______________|__________________________| |___________|  |___________|



   Figure 62. RAID Configuration Program - Disk Array Creation 

   5.  Press any key to return. 

   Now that an array has been defined, it is necessary to create the logical drives on this array.  Logical drive definitions for created arrays must be done before exiting the Create/Delete array menu. 

   Notes: 
   1.  Up to four arrays can be defined per controller. 
   2.  An array can be defined across the two channels of one controller. 
   3.  You cannot define an array across two controllers. 
   4.  For maximum performance and configuration flexibility, all installed drives should be configured into a single-disk array. Where data separation is desired, use separate logical drives on the same disk array. Each of these logical drives will appear as a separate physical disk to software programs like FDISK, and may be further divided into logical partitions. With this approach, if additional physical drives are added at a later date, they can be easily added as a second array without reconfiguring the original drives. 



Defining Logical Drives
 1.  Select Define logical drive from the Create/Delete Array menu. The 
       following screen appears: 


                IBM RAID Controller Configuration Ver 2.12
                               Adapter in Slot 1
             ____________________________     ___________    ___________ 
            |      Create/Delete Array   |   | _________ |  | _________ |
            |____________________________|   ||Ch      1||  ||Ch      2||
            |1. Help                     |   | _Bay      |  | _Bay      |
            |2. Define hot-spare drive   |   || Array __ |  || Array __ |
            |3. Delete disk array        |   |   _____   |  |   _____   |
            |4. Create disk array        |   |1 |     |  |  |1 |     |  |
            |5. Define Logical drive     |   |   _____   |  |   _____   |
            |6. Format drive             |   |2 |     |  |  |2 |     |  |
            |7. Exit                     |   |   _____   |  |   _____   |
            |____________________________|   |3 | HSP |  |  |3 |     |  |
                                             |   _____   |  |   _____   |
_______________ ___________________________  |4 | ONL | A|  |4 |     |  |
|Array Arrays  | Log  Size RAID   Date     | |   _____   |  |   _____   |
|ID    Size (MB)| Drv  (MB) Level  Created | |5 | ONL | A|  |5 |     |  |
|_______________|__________________________| |   _____   |  |   _____   |
| A    6450     |                          | |6 | ONL   A|  |6 |     |  |
|               |                          | |   _____   |  |   _____   |
|               |                          | |7 |     |  |  |7 |     |  |
|_______________|__________________________| |___________|  |___________|

   Figure 63. RAID Configuration Program - Logical Drive Definition 

   2.  Highlight array to be defined and press Enter. The define logical drive pop-up window appears. 



          IBM RAID Controller Configuration Ver 2.12
                 Adapter in Slot 1
 __________   ____________________________    ___________    ___________ 
|Select    |  |      Create/Delete Array  |  | _________ |  | _________ |
|RAID      |  |___________________________|  ||Ch      1||  ||Ch      2||
|Level     |  |1. Help                    |  | _Bay      |  | _Bay      |
|__________|  |2. Define hot-spare drive  |  || Array __ |  || Array __ |
|1. RAID-5 |  |3. Delete disk array       |  |   _____   |  |   _____   |
|2. RAID-0 |  |4. Create disk array       |  |1 |     |  |  |1 |     |  |
|3. RAID-1 |  |5. Define Logical drive    |  |   _____   |  |   _____   |
|__________|  |6. Format drive            |  |2 |     |  |  |2 |     |  |
              |7. Exit                    |  |   _____   |  |   _____   |
              |___________________________|  |3 | HSP |  |  |3 |     |  |
                                             |   _____   |  |   _____   |
 _________________________________________   |4 | ONL | A|  |4 |     |  |
|Array Arrays   | Log  Size RAID  Date    |  |   _____   |  |   _____   |
|ID    Size (MB)| Drv (MB) Level Created  |  |5 | ONL | A|  |5 |     |  |
|_______________|_________________________|  |   _____   |  |   _____   |
| A    6450     |                         |  |6 | ONL   A|  |6 |     |  |
|               |                         |  |   _____   |  |   _____   |
|               |                         |  |7 |     |  |  |7 |     |  |
|_______________|_________________________|  |___________|  |___________|


   Figure 64. RAID Configuration Program - Logical Drive Definition - Array Selection 

       Notes: 
       a.  If only one hard disk has been assigned to the array, RAID level 0 will be automatically assigned and the pop-up menu does not appear. 
       b.  If only two hard disks are assigned to the array, RAID-5 is not selectable, since at least three hard disk drives in an array are necessary to assign RAID level 5 to one of the logical drives. 
       c.  Define any RAID 5 logical drives first.  This is because the first logical drive seen will be the first RAID 5 drive created and will be assigned drive letter c:.  In this way, the operating system will be installed on a RAID 5 drive. 
       d.  The three RAID levels (0, 1 and 5) can be mixed in the same array allowing the user to chose the optimum RAID level for each data type. 
       e.  It is, however, not recommended to mix RAID 0 with the others levels if a hot-spare drive is defined, since an automatic rebuild would not be possible. 

   3.  Assign the RAID level wanted and press Enter. 
       The logical drive size pop-up menu shows the space available in this array for logical drives. 

       RAID 5 has been chosen in this example. 



            IBM RAID Controller Configuration Ver 2.12 
                        Adapter in Slot 1 

 ___________  ____________________________   ___________    ___________ 
|Enter Size ||      Create/Delete Array   |  | _________ |  | _________ |
|of Logical ||____________________________|  ||Ch      1||  ||Ch      2||
|Drive, (MB)||1. Help                     |  | _Bay      |  | _Bay      |
|___________||2. Define hot-spare drive   |  || Array __ |  || Array __ |
|:     4300 ||3. Delete disk array        |  |   _____   |  |   _____   |
|___________||4. Create disk array        |  |1 |     |  |  |1 |     |  |
             |5. Define Logical drive     |  |   _____   |  |   _____   |
             |6. Format drive             |  |2 |     |  |  |2 |     |  |
             |7. Exit                     |  |   _____   |  |   _____   |
             |____________________________|  |3 | HSP |  |  |3 |     |  |
                                             |   _____   |  |   _____   |
 _______________ ___________________________ |4 | ONL | A|  |4 |     |  |
|Array Arrays   | Log  Size RAID   Date  |  ||   _____   |  |   _____   |
|ID    Size (MB)| Drv  (MB) Level  Created  ||5 | ONL | A|  |5 |     |  |
|_______________|___________________________||   _____   |  |   _____   |
| A    6450     |                           ||6 | ONL   A|  |6 |     |  |
|               |                           ||   _____   |  |   _____   |
|               |                           ||7 |     |  |  |7 |     |  |
|_______________|___________________________||___________|  |___________|



 Figure 65. RAID Configuration Program - RAID Level Selection 

   4.  Enter the size needed, within the limitation (for example 400). 
   5.  Press Enter to confirm. 
   6.  As shown in Figure 66, information about the new logical drive appears in the logical drive list. 



                     IBM RAID Controller Configuration Ver 2.12
                                Adapter in Slot 1 

            ____________________________     ___________    ___________
           |      Create/Delete Array   |   | _________ |  | _________ |
           |____________________________|   ||Ch      1||  ||Ch      2||
           |1. Help                     |   | _Bay      |  | _Bay      |
           |2. Define hot-spare drive   |   || Array __ |  || Array __ |
           |3. Delete disk array        |   |   _____   |  |   _____   |
           |4. Create disk array        |   |1 |     |  |  |1 |     |  |
           |5. Define Logical drive     |   |   _____   |  |   _____   |
           |6. Format drive             |   |2 |     |  |  |2 |     |  |
           |7. Exit                     |   |   _____   |  |   _____   |
           |____________________________|   |3 | HSP |  |  |3 |     |  |
                                            |   _____   |  |   _____   |
_______________ __________________________  |4 | ONL | A|  |4 |     |  |
|Array Arrays   | Log Size RAID   Date    | |   _____   |  |   _____   |
|ID    Size (MB)| Drv (MB) Level Created  | |5 | ONL | A|  |5 |     |  |
|_______________|_________________________| |   _____   |  |   _____   |
| A    6450     | A0  400 RAID-5 08/24/95 | |6 | ONL   A|  |6 |     |  |
|               |                         | |   _____   |  |   _____   |
|               |                         | |7 |     |  |  |7 |     |  |
|_______________|_________________________| |___________|  |___________|


    Figure 66. RAID Configuration Program - Size Definition 

   7.  Repeat the procedures for the other logical drives and arrays. 
Note 
   It is not necessary to define multiple logical drive of same RAID level.  You can partition these logical drives the same way you partition a real disk when you install the operating system.
   8.  Select Exit to leave this menu. 
   9.  Select Yes to save the changes. 

       Figure 67 shows an example completed array definition which includes two logical drives:  one 400MB RAID-5 array and one 2925MB RAID-1 array. 



                      IBM RAID Controller Configuration Ver 2.12
                              Adapter in Slot 1 
                                              ___________    ___________ 
                                             | _________ |  | _________ |
                                             ||Ch      1||  ||Ch      2||
                                             | _Bay      |  | _Bay      |
                                             || Array __ |  || Array __ |
                                             |   _____   |  |   _____   |
                                             |1 |     |  |  |1 |     |  |
                                             |   _____   |  |   _____   |
                                             |2 |     |  |  |2 |     |  |
                                             |   _____   |  |   _____   |
                                             |3 | HSP |  |  |3 |     |  |
                                             |   _____   |  |   _____   |
 _______________ ___________________________ |4 | ONL | A|  |4 |     |  |
|Array Arrays   | Log  Size RAID   Date    | |   _____   |  |   _____   |
|ID    Size (MB)| Drv  (MB) Level  Created | |5 | ONL | A|  |5 |     |  |
|_______________|__________________________| |   _____   |  |   _____   |
| A    6450     | A0   400 RAID-5 08/24/95 | |6 | ONL   A|  |6 |     |  |
|               | A1  2925 RAID-1 08/24/95 | |   _____   |  |   _____   |
|               |                          | |7 |     |  |  |7 |     |  |
|_______________|__________________________| |___________|  |___________|


Figure 67. RAID Configuration Program - Result 



Setting the Write Policy
Now that the logical drives have been created, you may wish to change the write policy for these drives. 

If you want to change the write policy: 
   1.  Select Advanced functions from the main menu. 
   2.  Select Change write policy. 
   3.  Use the up and down arrow keys to select the logical drive. 
   4.  Press Enter to toggle the write policy. 

The different options are: 
   WB for Write-Back:  In the write-back mode, the completion status is sent    before the data is actually written to the drives.  While this mode will yield higher performance, it is critical to protect the DASD power to ensure the write operations actually complete, since the processor thinks the operation has been completed. 
  WT for Write-Through:  In write-through mode, the data is written directly to disk and no acknowledgement is sent until the operation is complete. 



Initializing the Array
If you are using RAID Level 1 or 5, you must select Initialize logical drives for proper operation. This sets the drive to a predetermined state. Any data existing on the drive is overwritten with zeros, and the corresponding parity is initialized to the correct value. 
1.  Select Initialize/synchronize array from the main menu. 
2.  Select Initialize logical drive. 
3.  Select the logical drive you want to initialize by pressing the spacebar. 
4.  Press Enter to start the initialization. 
5.  Select Yes to confirm. 


Backup/Restoring the Configuration
Attention!
   The array configuration is stored on EEPROM on the adapter.  It is very important to back up this configuration on a diskette.  If the adapter ever needs to be replaced, the configuration can be restored to the new adapter without the need to reconfigure the array. Otherwise, the array would need to be redefined and your data would be lost. 
     This is important not only at installation time but whenever the array configuration changes.  For example, if a hot-spare drive is defined and subsequently, a drive fails and the hot-spare is enabled, the array configuration is updated.  If you are unable to restore the configuration exactly as it was before, it would have the same effect as re-initializing the arrays: all data would be lost. We strongly recommend that the configuration be backed up.

To back up the configuration: 
   1.  Select Advanced functions from the Main Menu. 
   2.  Select Backup config. to diskette. 
   3.  Press Enter. 
   4.  Enter the filename you want for backup (config is the default). 
   5.  Insert a diskette to hold the backup file. 
   6.  Press Enter. 

To restore the configuration:
   1.  Select Advanced functions from the Main Menu. 
   2.  Select Restore config. from diskette. 
   3.  Press Enter. 
   4.  Enter the filename you used for backup. 
   5.  Insert the diskette used for backup. 
   6.  Press Enter. 

       A screen like the one in Figure 68 will appear.  This shows you the date when the backup was performed. 



          IBM RAID Controller Configuration Ver 2.12
                   Adapter in Slot 1 (2.14) 

 _________              _______________________________ 
| Confirm |            |      Advanced Functions       |
|_________|            |_______________________________|
| 1. No   |            |1. Help                        |
| 2. Yes  |            |2. Backup config. to diskette  |
|_________|            |3. Restore config. to diskette |
                       |4. Change write policy         |
                       |5. Format drive                |
                       |6. Change RAID parameters      |
                       |7. Exit                        |
                       |_______________________________|
 ______________________________________________ 
| File backed up on Aug 24, 1995 at 18:33:37   |
|______________________________________________|



   Figure 68. RAID Configuration Program - Advanced Functions Menu 

   7.  Select Yes to confirm. 
 

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