After installing a Mylex RAID controller, you should see a message similar to the fol-lowing when you power on the system:
Scanning Option ROMs...
Mylex AcceleRAID 352 BIOS PLUS V6.01-30 (Nov 14, 2001) Copyright (c) 2001 IBM Corporation. All rights reserved.
www.mylex.com
Spinning up drives...
AcceleRAID 352 Firmware Version 7.00-03 RAID Adapter Serial #: 10026500327
PCI Address: F0000000 Bus=2 Dev/Slot=13 Function=0 IRQ=9 Adapter Memory Size = 64 MB (SDRAM/ECC)
BIOS Enabled - 8 GB Disk Drive Geometry Selected.
Press <ALT-M> for BIOS options
Press <ALT-R> for RAID Configuration options No system drives installed
If arrays had already been defined, the last line would have displayed the number of arrays (logical drives) in the controller’s configuration. The banner also displays the amount of memory installed in the controller, the firmware version, and the card’s PCI address, location, and interrupt.
BIOS options
PressALT-Mto enter the BIOS options menu. There are three options, each of which controls the card’s ability to boot the system.
BIOS enabled/disabled
The BIOS must be enabled if you wish to boot from disks, arrays, or CD-ROM drives connected to the controller. If you don’t want to boot from these devices, you can disable the BIOS and shave a few seconds off the system startup. The remaining options do not apply if this option is disabled.
CD-ROM boot enabled/disabled
If you want to boot from a CD-ROM drive that is connected to your Mylex con-troller, this option must be enabled. Remember that using a slower device (such as a CD-ROM) on a fast SCSIchannel will cause the entire channel to run at the speed of the slowest device. You probably don’t want to connect a CD-ROM to an expensive RAID controller. However, this option is quite useful for system installation. Disable it when you’re done using the CD-ROM, and don’t forget to disconnect the drive.
2 GB/8 GB drive geometry
This option selects how much of an array/disk the BIOS can address. When set to 2 GB, the controller can boot only operating systems found in the first 2 GB of the logical drives that you define. When you use an 8 GB drive geometry, the controller can use the first 8 GB. Set this option before installing an operating system.
EzAssist (RAID configuration)
EzAssist is the primary utility used to configure Mylex controllers and arrays. It is normally invoked when the controller initializes, but can also be installed on a floppy disk and run from an MS-DOS compatible operating system. The latter option is use-ful when attempts to enter EzAssist at system startup fail. You can download EzAssist from the Mylex web site.
After you pressALT-R to enter the EzAssist RAID configuration menu, the following messages appear on the screen:
Checking RAID Configuration Software ...
Loading RAID Configuration Software ...
Starting RAID Configuration Software ...
An ASCII animation of the forward slash and backslash characters will appear imme-diately following the last line. Be aware that on slow systems, it could take some time for the software to start, and the animation will move slowly.
Once the software loads, you will be presented with a list of all Mylex controllers connected to the system. In many cases, you will see a single controller with an entry such as the following:
Controller PCI PCI PCI Firmware No. Model Bus Device Function Version
0 AcceleRAID 352 2 13 0 7.00-03
Navigate the list using the arrow keys and pressENTERwhen the controller that you wish to administer is highlighted. After rescanning the SCSIbus, if no arrays are cur-rently defined and there are disks connected to the controller, EzAssist will ask if you wish to configure a new array. Otherwise, the following menu options are presented:
• Configure a RAID Drive
• View or Modify Controller Configuration
• Perform Administration On ...
• Rescan for New Devices
• Advanced Options
In order for you to install any operating system on disks connected to a Mylex con-troller, at least one array must be defined. If you already have an operating system
installed, you can create additional arrays using either the EzAssist BIOS utility or the Global Array Manager, once Linux has booted.
Configuring the first array
Before you can install Linux, at least one array must be created. The following instructions explain how to configure an array.
1. UseALT-R to enter the EzAssist RAID configuration utility.
2. Select your controller.
3. If a dialog pops up, warning that no configuration was detected, answer yes.
Otherwise, choose Configure RAID Drive from the main menu.
4. A menu with three configuration methods will appear: Automatic, Assisted, and Custom. Choose Custom and then select Configure a New Disk Array from the menu that appears.
5. The next menu contains a list of all disks connected to the controller, organized by SCSIID. Select all the disks that you want to include in the new array by highlighting them and pressing the ENTER key. When you are done selecting disks, navigate to and choose Save Array.
6. If there are other unconfigured disks connected to the controller, a dialog will appear, asking if you want to configure logical drives. Choose yes, and then select the array that you just defined from the pop-up dialog that follows.
7. The next screen displays information about your new array. Use the arrow keys to move between fields and make any necessary changes to the array configura-tion. You can change the RAID level, cache type, and stripe size. In addition, you can alter the array’s logical size by moving to the logical size field, using the arrow keys, and typing in the new logical drive size. Changing an array’s logical size is useful for splitting a single array into two or more smaller logical drives.
As mentioned earlier in this chapter, the DAC960/DAC1100 driver supports only seven disk partitions. So if you need more than that for a large array, you will have to split up the array into more than one logical drive. See the “Parti-tion Limita“Parti-tions” and “Logical Drives” sec“Parti-tions, earlier in this chapter.
8. After you have customized your array settings, use the TAB key to activate the menu on the right side of the screen. Then select Add Disk.
9. The array now appears in the dialog window at the bottom of the screen. If you changed the logical size of the array, you have the option to add another logical disk that contains some or all of the remaining space. If you want to add another logical disk, simply tune the array’s configuration, as described in step 7, and then repeat step 8. You can also leave the remaining space unallocated and con-figure it later, but you won’t be able to access it until you’ve assigned it to a logi-cal drive.
10. Choose Apply to commit the array to the controller’s memory.
After you select the Apply option, the new configuration is written to the control-ler’s memory, and after a few seconds, you are returned to the main menu. If you cre-ated arrays that use redundancy (such as RAID-1 or RAID-5), the initial synchronization process will commence. You can monitor the progress of the rebuild process by selecting Advanced Options and then Background Tasks from EzAssist’s main menu. You can now reboot the system and install a new operating system on the array that you just created, or wait until the rebuild process is complete. You may also create additional arrays and fine-tune the controller. See “The DAC960” sec-tion, earlier in this chapter.
Configuring an existing disk for standalone JBOD mode
Mylex controllers do not operate in pass-through mode for JBOD. If you are replac-ing an existreplac-ing SCSIcontroller with a Mylex RAID controller and want to access an operating system that was already installed on a single physical disk, you will need to create a logical JBOD drive first.
Before connecting existing disks to the new controller and creating a logical JBOD drive, you should take a few preparatory steps. You can install the Mylex controller along with your existing SCSIcontroller, or you can wait until you’ve completed the first six steps and then swap controllers. It’s advisable, but not required, to perform steps 1–6 in single-user mode. Ialso recommend creating a backup copy of /etc/lilo.
conf and /etc/fstab before proceeding. It’s also a good idea to have a rescue floppy disk or CD-ROM handy.
1. Reconfigure the kernel so that it supports Mylex controllers (see “The DAC960 Driver” section, earlier in this chapter).
2. Copy the new kernel and System.map to /boot.
3. Edit /etc/lilo.conf and add a new kernel stanza that uses the new kernel. It’s essential that this new stanza contain a root line that points to the device special file for the new root partition. So if your current root partition is /dev/sda2, cre-ate a root line that readsroot=/dev/rd/c0d0p2. In this case, your system disk will be connected to the first channel of the first Mylex controller and appear as logi-cal drive 0. Use a device file that will reflect your new system configuration. In general, you probably want any system disk in JBOD mode to be the first logical drive on the first controller.
4. If /etc/lilo.conf contains a boot line, remove it. You can add a new boot line after the new controller is installed and the system is brought back online.
5. Execute /sbin/lilo to rebuild the master boot record.
6. Edit /etc/fstab to reflect the new Mylex device files. On modern systems that use disk labels, you will likely need to change only the swap entry (which always uses a real device entry instead of a disk label). Thus, if your swap file is located at /dev/sda3, change it to /dev/rd/c0d0p3 to indicate partition three on the first logical drive of the first controller.
7. At this point, you should power down the system and install the new controller.
If the controller is already installed, move your existing disk to the Mylex con-troller and then power-on the system.
8. UseALT-R to enter the EzAssist RAID configuration utility.
9. Select the controller that is connected to your existing system disk.
10. If a dialog warning pops up, saying that no configuration was detected, answer yes, and a configuration menu will appear. Otherwise, choose Configure RAID Drive from the main menu.
11. A menu with three configuration methods will appear: Automatic, Assisted, and Custom. Choose Custom, and then select Configure a New Disk Array from the menu that appears.
12. This menu contains a list of all disks connected to the controller, organized by SCSIID. Select the disk that you want to configure for JBOD mode (see step 3) by highlighting it and pressing theENTERkey. Then navigate to, and select, Save Array.
13. If there are other unconfigured disks connected to the controller, a dialog asking if you want to configure logical drives will appear. Choose yes, and then select the array that you just defined from the pop-up dialog that appears next.
14. The next screen displays information about your new JBOD array. Since only one disk was included in the array, JBOD is the only array type available. You can optionally change the write cache type and stripe size as needed.
15. Use theTABkey to activate the menu on the right side of the screen. Then select Add Disk. The array now appears in the dialog window at the bottom of the screen. Choose Apply to commit the array to the controller’s memory.
Once you apply the configuration, a window appears indicating that the new array configuration is being stored in the controller. After a few seconds, you will be returned to the main menu, or to the array creation menu, if there are additional free disks connected to the system. You can now continue to define additional arrays or exit EzAssist and reboot the system.
When the system reboots, your original system disk (now a JBOD mode array) is accessible just like a normal disk, and the operating system boot prompt appears. If the kernel panics, or you encounter unrecoverable problems, simply boot into res-cue mode from a floppy disk or CD-ROM and fine-tune /etc/lilo.conf and /etc/fstab.
Don’t forget that if you make changes to /etc/lilo.conf, you will need to rerun /sbin/
lilo to update the boot sector. If all else fails, you will still be able to re-install your original disk controller and access the system, although you will have to use a rescue disk to restore the original settings to /etc/lilo.conf and /etc/fstab.
Converting an existing standalone disk to a mirror
Unfortunately, there is no simple, automatic way to create a new mirror and include a disk with existing data as one of its components. To accomplish the job, start by following the procedures outlined in the previous section. Once the system is work-ing in JBOD with the new Mylex controller, follow these steps:
1. Reboot the system and useALT-Rto enter the EzAssist RAID configuration util-ity.
2. Select the controller to which your JBOD logical drive is connected.
3. From the main menu, choose Perform Administration On and then select Logi-cal Drive.
4. A pop-up window appears that lists all your logical drives. Choose the drive that you wish to convert to a RAID-1.
5. Now select Advanced Options and Delete Logical Drive. There is a short delay while the RAID configuration is updated.
6. Use theESCkey to return to EzAssist’s main menu. Then choose the first option:
Configure RAID Drive.
7. A menu with three configuration methods will appear: Automatic, Assisted, and Custom. Choose Custom and then select Configure a New Disk Array from the menu that appears.
8. The next menu contains a list of all disks connected to the controller, organized by SCSIID. First, select the disk that used to be the JBOD mode disk by high-lighting it and pressing theENTER key.
9. Now select another available disk. This will become the second mirror compo-nent. It’s important to choose the former JBOD system disk first, since it con-tains the data. If you want to create a mirror that has more than two member disks, you can select additional disks now.
10. When you’re done selecting disks, navigate using theTAB key and select Save Array.
11. If there are other unconfigured disks connected to the controller, a dialog will appear, asking if you want to configure logical drives. Choose yes and then select the array that you just defined from the pop-up dialog that appears next.
12. The next screen displays information about your new array. Since two disks were included in the array, RAID-1 is the default array type. You can optionally change the write cache type and stripe size as needed.
Depending on how many disks you have selected for inclusion in your new RAID-1, EzAssist will allow you to change the RAID level on the Logical Drive Definition screen. Changing the RAID level to anything other than RAID-1 will be catastrophic and result in total data loss from the previous system.
13. Use theTABkey to activate the menu on the right side of the screen. Then select Add Disk. The array now appears in the dialog window at the bottom of the screen. Choose Apply to commit the array to the controller’s memory.
14. After the new configuration is written to the controller, return to the main menu and select Perform Administration On➝ Physical Device.
15. A list of disks is presented. Select the second disk in the array—that is, the disk that has no preexisting data.
16. Choose Advanced Options from the menu that appears and then select Make Drive Offline.
17. A two-step confirmation appears. Answer yes to both questions. Now the drive is marked offline.
18. Finally, return to the main menu and choose Perform Administration On➝ Log-ical Drive.
19. Select the array that contains the member disk that you just marked offline; the disk will appear highlighted and in critical condition.
20. Choose Advanced Options and Rebuild Redundancy Data from the menu that pops up.
21. A confirmation appears. Answer affirmatively. After a short pause, you are returned to the array status menu, and the array is now marked as rebuilding.
You can monitor the progress of the rebuild process by selecting Advanced Options and then Background Tasks from EzAssist’s main menu. After the rebuild process has completed, you can reboot your system. System partitions that were on the origi-nal JBOD logical drive are now mirrored.
In general, you can delete any JBOD disk and create a new RAID-1 with the former JBOD drive as its first component. The process also works in the other direction.
Delete any mirror and then create a JBOD logical drive that contains a former RAID-1 member to return to single disk operation.