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   Linux Driver for Mylex DAC960/AcceleRAID/eXtremeRAID PCI RAID Controllers

                        Version 2.2.11 for Linux 2.2.19

                        Version 2.4.11 for Linux 2.4.12

                              PRODUCTION RELEASE

                                11 October 2001

                               Leonard N. Zubkoff

                               Dandelion Digital

                               lnz@dandelion.com

         Copyright 1998-2001 by Leonard N. Zubkoff 

                                 INTRODUCTION

Mylex, Inc. designs and manufactures a variety of high performance PCI RAID

controllers.  Mylex Corporation is located at 34551 Ardenwood Blvd., Fremont,

California 94555, USA and can be reached at 510.796.6100 or on the World Wide

Web at http://www.mylex.com.  Mylex Technical Support can be reached by

electronic mail at mylexsup@us.ibm.com, by voice at 510.608.2400, or by FAX at

510.745.7715.  Contact information for offices in Europe and Japan is available

on their Web site.

The latest information on Linux support for DAC960 PCI RAID Controllers, as

well as the most recent release of this driver, will always be available from

my Linux Home Page at URL "http://www.dandelion.com/Linux/".  The Linux DAC960

driver supports all current Mylex PCI RAID controllers including the new

eXtremeRAID 2000/3000 and AcceleRAID 352/170/160 models which have an entirely

new firmware interface from the older eXtremeRAID 1100, AcceleRAID 150/200/250,

and DAC960PJ/PG/PU/PD/PL.  See below for a complete controller list as well as

minimum firmware version requirements.  For simplicity, in most places this

documentation refers to DAC960 generically rather than explicitly listing all

the supported models.

Driver bug reports should be sent via electronic mail to "lnz@dandelion.com".

Please include with the bug report the complete configuration messages reported

by the driver at startup, along with any subsequent system messages relevant to

the controller's operation, and a detailed description of your system's

hardware configuration.  Driver bugs are actually quite rare; if you encounter

problems with disks being marked offline, for example, please contact Mylex

Technical Support as the problem is related to the hardware configuration

rather than the Linux driver.

Please consult the RAID controller documentation for detailed information

regarding installation and configuration of the controllers.  This document

primarily provides information specific to the Linux support.

                                DRIVER FEATURES

The DAC960 RAID controllers are supported solely as high performance RAID

controllers, not as interfaces to arbitrary SCSI devices.  The Linux DAC960

driver operates at the block device level, the same level as the SCSI and IDE

drivers.  Unlike other RAID controllers currently supported on Linux, the

DAC960 driver is not dependent on the SCSI subsystem, and hence avoids all the

complexity and unnecessary code that would be associated with an implementation

as a SCSI driver.  The DAC960 driver is designed for as high a performance as

possible with no compromises or extra code for compatibility with lower

performance devices.  The DAC960 driver includes extensive error logging and

online configuration management capabilities.  Except for initial configuration

of the controller and adding new disk drives, most everything can be handled

from Linux while the system is operational.

The DAC960 driver is architected to support up to 8 controllers per system.

Each DAC960 parallel SCSI controller can support up to 15 disk drives per

channel, for a maximum of 60 drives on a four channel controller; the fibre

channel eXtremeRAID 3000 controller supports up to 125 disk drives per loop for

a total of 250 drives.  The drives installed on a controller are divided into

one or more "Drive Groups", and then each Drive Group is subdivided further

into 1 to 32 "Logical Drives".  Each Logical Drive has a specific RAID Level

and caching policy associated with it, and it appears to Linux as a single

block device.  Logical Drives are further subdivided into up to 7 partitions

through the normal Linux and PC disk partitioning schemes.  Logical Drives are

also known as "System Drives", and Drive Groups are also called "Packs".  Both

terms are in use in the Mylex documentation; I have chosen to standardize on

the more generic "Logical Drive" and "Drive Group".

DAC960 RAID disk devices are named in the style of the obsolete Device File

System (DEVFS).  The device corresponding to Logical Drive D on Controller C

is referred to as /dev/rd/cCdD, and the partitions are called /dev/rd/cCdDp1

through /dev/rd/cCdDp7.  For example, partition 3 of Logical Drive 5 on

Controller 2 is referred to as /dev/rd/c2d5p3.  Note that unlike with SCSI

disks the device names will not change in the event of a disk drive failure.

The DAC960 driver is assigned major numbers 48 - 55 with one major number per

controller.  The 8 bits of minor number are divided into 5 bits for the Logical

Drive and 3 bits for the partition.

          SUPPORTED DAC960/AcceleRAID/eXtremeRAID PCI RAID CONTROLLERS

The following list comprises the supported DAC960, AcceleRAID, and eXtremeRAID

PCI RAID Controllers as of the date of this document.  It is recommended that

anyone purchasing a Mylex PCI RAID Controller not in the following table

contact the author beforehand to verify that it is or will be supported.

eXtremeRAID 3000

            1 Wide Ultra-2/LVD SCSI channel

            2 External Fibre FC-AL channels

            233MHz StrongARM SA 110 Processor

            64 Bit 33MHz PCI (backward compatible with 32 Bit PCI slots)

            32MB/64MB ECC SDRAM Memory

eXtremeRAID 2000

            4 Wide Ultra-160 LVD SCSI channels

            233MHz StrongARM SA 110 Processor

            64 Bit 33MHz PCI (backward compatible with 32 Bit PCI slots)

            32MB/64MB ECC SDRAM Memory

AcceleRAID 352

            2 Wide Ultra-160 LVD SCSI channels

            100MHz Intel i960RN RISC Processor

            64 Bit 33MHz PCI (backward compatible with 32 Bit PCI slots)

            32MB/64MB ECC SDRAM Memory

AcceleRAID 170

            1 Wide Ultra-160 LVD SCSI channel

            100MHz Intel i960RM RISC Processor

            16MB/32MB/64MB ECC SDRAM Memory

AcceleRAID 160 (AcceleRAID 170LP)

            1 Wide Ultra-160 LVD SCSI channel

            100MHz Intel i960RS RISC Processor

            Built in 16M ECC SDRAM Memory

            PCI Low Profile Form Factor - fit for 2U height

eXtremeRAID 1100 (DAC1164P)

            3 Wide Ultra-2/LVD SCSI channels

            233MHz StrongARM SA 110 Processor

            64 Bit 33MHz PCI (backward compatible with 32 Bit PCI slots)

            16MB/32MB/64MB Parity SDRAM Memory with Battery Backup

AcceleRAID 250 (DAC960PTL1)

            Uses onboard Symbios SCSI chips on certain motherboards

            Also includes one onboard Wide Ultra-2/LVD SCSI Channel

            66MHz Intel i960RD RISC Processor

            4MB/8MB/16MB/32MB/64MB/128MB ECC EDO Memory

AcceleRAID 200 (DAC960PTL0)

            Uses onboard Symbios SCSI chips on certain motherboards

            Includes no onboard SCSI Channels

            66MHz Intel i960RD RISC Processor

            4MB/8MB/16MB/32MB/64MB/128MB ECC EDO Memory

AcceleRAID 150 (DAC960PRL)

            Uses onboard Symbios SCSI chips on certain motherboards

            Also includes one onboard Wide Ultra-2/LVD SCSI Channel

            33MHz Intel i960RP RISC Processor

            4MB Parity EDO Memory

DAC960PJ    1/2/3 Wide Ultra SCSI-3 Channels

            66MHz Intel i960RD RISC Processor

            4MB/8MB/16MB/32MB/64MB/128MB ECC EDO Memory

DAC960PG    1/2/3 Wide Ultra SCSI-3 Channels

            33MHz Intel i960RP RISC Processor

            4MB/8MB ECC EDO Memory

DAC960PU    1/2/3 Wide Ultra SCSI-3 Channels

            Intel i960CF RISC Processor

            4MB/8MB EDRAM or 2MB/4MB/8MB/16MB/32MB DRAM Memory

DAC960PD    1/2/3 Wide Fast SCSI-2 Channels

            Intel i960CF RISC Processor

            4MB/8MB EDRAM or 2MB/4MB/8MB/16MB/32MB DRAM Memory

DAC960PL    1/2/3 Wide Fast SCSI-2 Channels

            Intel i960 RISC Processor

            2MB/4MB/8MB/16MB/32MB DRAM Memory

DAC960P     1/2/3 Wide Fast SCSI-2 Channels

            Intel i960 RISC Processor

            2MB/4MB/8MB/16MB/32MB DRAM Memory

For the eXtremeRAID 2000/3000 and AcceleRAID 352/170/160, firmware version

6.00-01 or above is required.

For the eXtremeRAID 1100, firmware version 5.06-0-52 or above is required.

For the AcceleRAID 250, 200, and 150, firmware version 4.06-0-57 or above is

required.

For the DAC960PJ and DAC960PG, firmware version 4.06-0-00 or above is required.

For the DAC960PU, DAC960PD, DAC960PL, and DAC960P, either firmware version

3.51-0-04 or above is required (for dual Flash ROM controllers), or firmware

version 2.73-0-00 or above is required (for single Flash ROM controllers)

Please note that not all SCSI disk drives are suitable for use with DAC960

controllers, and only particular firmware versions of any given model may

actually function correctly.  Similarly, not all motherboards have a BIOS that

properly initializes the AcceleRAID 250, AcceleRAID 200, AcceleRAID 150,

DAC960PJ, and DAC960PG because the Intel i960RD/RP is a multi-function device.

If in doubt, contact Mylex RAID Technical Support (mylexsup@us.ibm.com) to

verify compatibility.  Mylex makes available a hard disk compatibility list at

http://www.mylex.com/support/hdcomp/hd-lists.html.

                              DRIVER INSTALLATION

This distribution was prepared for Linux kernel version 2.2.19 or 2.4.12.

To install the DAC960 RAID driver, you may use the following commands,

replacing "/usr/src" with wherever you keep your Linux kernel source tree:

  cd /usr/src

  tar -xvzf DAC960-2.2.11.tar.gz (or DAC960-2.4.11.tar.gz)

  mv README.DAC960 linux/Documentation

  mv DAC960.[ch] linux/drivers/block

  patch -p0 < DAC960.patch (if DAC960.patch is included)

  cd linux

  make config

  make bzImage (or zImage)

Then install "arch/i386/boot/bzImage" or "arch/i386/boot/zImage" as your

standard kernel, run lilo if appropriate, and reboot.

To create the necessary devices in /dev, the "make_rd" script included in

"DAC960-Utilities.tar.gz" from http://www.dandelion.com/Linux/ may be used.

LILO 21 and FDISK v2.9 include DAC960 support; also included in this archive

are patches to LILO 20 and FDISK v2.8 that add DAC960 support, along with

statically linked executables of LILO and FDISK.  This modified version of LILO

will allow booting from a DAC960 controller and/or mounting the root file

system from a DAC960.

Red Hat Linux 6.0 and SuSE Linux 6.1 include support for Mylex PCI RAID

controllers.  Installing directly onto a DAC960 may be problematic from other

Linux distributions until their installation utilities are updated.

                              INSTALLATION NOTES

Before installing Linux or adding DAC960 logical drives to an existing Linux

system, the controller must first be configured to provide one or more logical

drives using the BIOS Configuration Utility or DACCF.  Please note that since

there are only at most 6 usable partitions on each logical drive, systems

requiring more partitions should subdivide a drive group into multiple logical

drives, each of which can have up to 6 usable partitions.  Also, note that with

large disk arrays it is advisable to enable the 8GB BIOS Geometry (255/63)

rather than accepting the default 2GB BIOS Geometry (128/32); failing to so do

will cause the logical drive geometry to have more than 65535 cylinders which

will make it impossible for FDISK to be used properly.  The 8GB BIOS Geometry

can be enabled by configuring the DAC960 BIOS, which is accessible via Alt-M

during the BIOS initialization sequence.

For maximum performance and the most efficient E2FSCK performance, it is

recommended that EXT2 file systems be built with a 4KB block size and 16 block

stride to match the DAC960 controller's 64KB default stripe size.  The command

"mke2fs -b 4096 -R stride=16 " is appropriate.  Unless there will be a

large number of small files on the file systems, it is also beneficial to add

the "-i 16384" option to increase the bytes per inode parameter thereby

reducing the file system metadata.  Finally, on systems that will only be run

with Linux 2.2 or later kernels it is beneficial to enable sparse superblocks

with the "-s 1" option.

                      DAC960 ANNOUNCEMENTS MAILING LIST

The DAC960 Announcements Mailing List provides a forum for informing Linux

users of new driver releases and other announcements regarding Linux support

for DAC960 PCI RAID Controllers.  To join the mailing list, send a message to

"dac960-announce-request@dandelion.com" with the line "subscribe" in the

message body.

                CONTROLLER CONFIGURATION AND STATUS MONITORING

The DAC960 RAID controllers running firmware 4.06 or above include a Background

Initialization facility so that system downtime is minimized both for initial

installation and subsequent configuration of additional storage.  The BIOS

Configuration Utility (accessible via Alt-R during the BIOS initialization

sequence) is used to quickly configure the controller, and then the logical

drives that have been created are available for immediate use even while they

are still being initialized by the controller.  The primary need for online

configuration and status monitoring is then to avoid system downtime when disk

drives fail and must be replaced.  Mylex's online monitoring and configuration

utilities are being ported to Linux and will become available at some point in

the future.  Note that with a SAF-TE (SCSI Accessed Fault-Tolerant Enclosure)

enclosure, the controller is able to rebuild failed drives automatically as

soon as a drive replacement is made available.

The primary interfaces for controller configuration and status monitoring are

special files created in the /proc/rd/... hierarchy along with the normal

system console logging mechanism.  Whenever the system is operating, the DAC960

driver queries each controller for status information every 10 seconds, and

checks for additional conditions every 60 seconds.  The initial status of each

controller is always available for controller N in /proc/rd/cN/initial_status,

and the current status as of the last status monitoring query is available in

/proc/rd/cN/current_status.  In addition, status changes are also logged by the

driver to the system console and will appear in the log files maintained by

syslog.  The progress of asynchronous rebuild or consistency check operations

is also available in /proc/rd/cN/current_status, and progress messages are

logged to the system console at most every 60 seconds.

Starting with the 2.2.3/2.0.3 versions of the driver, the status information

available in /proc/rd/cN/initial_status and /proc/rd/cN/current_status has been

augmented to include the vendor, model, revision, and serial number (if

available) for each physical device found connected to the controller:

***** DAC960 RAID Driver Version 2.2.3 of 19 August 1999 *****

Copyright 1998-1999 by Leonard N. Zubkoff 

Configuring Mylex DAC960PRL PCI RAID Controller

  Firmware Version: 4.07-0-07, Channels: 1, Memory Size: 16MB

  PCI Bus: 1, Device: 4, Function: 1, I/O Address: Unassigned

  PCI Address: 0xFE300000 mapped at 0xA0800000, IRQ Channel: 21

  Controller Queue Depth: 128, Maximum Blocks per Command: 128

  Driver Queue Depth: 127, Maximum Scatter/Gather Segments: 33

  Stripe Size: 64KB, Segment Size: 8KB, BIOS Geometry: 255/63

  SAF-TE Enclosure Management Enabled

  Physical Devices:

    0:0  Vendor: IBM       Model: DRVS09D           Revision: 0270

         Serial Number:       68016775HA

         Disk Status: Online, 17928192 blocks

    0:1  Vendor: IBM       Model: DRVS09D           Revision: 0270

         Serial Number:       68004E53HA

         Disk Status: Online, 17928192 blocks

    0:2  Vendor: IBM       Model: DRVS09D           Revision: 0270

         Serial Number:       13013935HA

         Disk Status: Online, 17928192 blocks

    0:3  Vendor: IBM       Model: DRVS09D           Revision: 0270

         Serial Number:       13016897HA

         Disk Status: Online, 17928192 blocks

    0:4  Vendor: IBM       Model: DRVS09D           Revision: 0270

         Serial Number:       68019905HA

         Disk Status: Online, 17928192 blocks

    0:5  Vendor: IBM       Model: DRVS09D           Revision: 0270

         Serial Number:       68012753HA

         Disk Status: Online, 17928192 blocks

    0:6  Vendor: ESG-SHV   Model: SCA HSBP M6       Revision: 0.61

  Logical Drives:

    /dev/rd/c0d0: RAID-5, Online, 89640960 blocks, Write Thru

  No Rebuild or Consistency Check in Progress

To simplify the monitoring process for custom software, the special file

/proc/rd/status returns "OK" when all DAC960 controllers in the system are

operating normally and no failures have occurred, or "ALERT" if any logical

drives are offline or critical or any non-standby physical drives are dead.

Configuration commands for controller N are available via the special file

/proc/rd/cN/user_command.  A human readable command can be written to this

special file to initiate a configuration operation, and the results of the

operation can then be read back from the special file in addition to being

logged to the system console.  The shell command sequence

  echo "" > /proc/rd/c0/user_command

  cat /proc/rd/c0/user_command

is typically used to execute configuration commands.  The configuration

commands are:

  flush-cache

    The "flush-cache" command flushes the controller's cache.  The system

    automatically flushes the cache at shutdown or if the driver module is

    unloaded, so this command is only needed to be certain a write back cache

    is flushed to disk before the system is powered off by a command to a UPS.

    Note that the flush-cache command also stops an asynchronous rebuild or

    consistency check, so it should not be used except when the system is being

    halted.

  kill :

    The "kill" command marks the physical drive : as DEAD.

    This command is provided primarily for testing, and should not be used

    during normal system operation.

  make-online :

    The "make-online" command changes the physical drive :

    from status DEAD to status ONLINE.  In cases where multiple physical drives

    have been killed simultaneously, this command may be used to bring all but

    one of them back online, after which a rebuild to the final drive is

    necessary.

    Warning: make-online should only be used on a dead physical drive that is

    an active part of a drive group, never on a standby drive.  The command

    should never be used on a dead drive that is part of a critical logical

    drive; rebuild should be used if only a single drive is dead.

  make-standby :

    The "make-standby" command changes physical drive :

    from status DEAD to status STANDBY.  It should only be used in cases where

    a dead drive was replaced after an automatic rebuild was performed onto a

    standby drive.  It cannot be used to add a standby drive to the controller

    configuration if one was not created initially; the BIOS Configuration

    Utility must be used for that currently.

  rebuild :

    The "rebuild" command initiates an asynchronous rebuild onto physical drive

    :.  It should only be used when a dead drive has been

    replaced.

  check-consistency 

    The "check-consistency" command initiates an asynchronous consistency check

    of  with automatic restoration.  It can be used

    whenever it is desired to verify the consistency of the redundancy

    information.

  cancel-rebuild

  cancel-consistency-check

    The "cancel-rebuild" and "cancel-consistency-check" commands cancel any

    rebuild or consistency check operations previously initiated.

               EXAMPLE I - DRIVE FAILURE WITHOUT A STANDBY DRIVE

The following annotated logs demonstrate the controller configuration and and

online status monitoring capabilities of the Linux DAC960 Driver.  The test

configuration comprises 6 1GB Quantum Atlas I disk drives on two channels of a

DAC960PJ controller.  The physical drives are configured into a single drive

group without a standby drive, and the drive group has been configured into two

logical drives, one RAID-5 and one RAID-6.  Note that these logs are from an

earlier version of the driver and the messages have changed somewhat with newer

releases, but the functionality remains similar.  First, here is the current

status of the RAID configuration:

gwynedd:/u/lnz# cat /proc/rd/c0/current_status

***** DAC960 RAID Driver Version 2.0.0 of 23 March 1999 *****

Copyright 1998-1999 by Leonard N. Zubkoff 

Configuring Mylex DAC960PJ PCI RAID Controller

  Firmware Version: 4.06-0-08, Channels: 3, Memory Size: 8MB

  PCI Bus: 0, Device: 19, Function: 1, I/O Address: Unassigned

  PCI Address: 0xFD4FC000 mapped at 0x8807000, IRQ Channel: 9

  Controller Queue Depth: 128, Maximum Blocks per Command: 128

  Driver Queue Depth: 127, Maximum Scatter/Gather Segments: 33

  Stripe Size: 64KB, Segment Size: 8KB, BIOS Geometry: 255/63

  Physical Devices:

    0:1 - Disk: Online, 2201600 blocks

    0:2 - Disk: Online, 2201600 blocks

    0:3 - Disk: Online, 2201600 blocks

    1:1 - Disk: Online, 2201600 blocks

    1:2 - Disk: Online, 2201600 blocks

    1:3 - Disk: Online, 2201600 blocks

  Logical Drives:

    /dev/rd/c0d0: RAID-5, Online, 5498880 blocks, Write Thru

    /dev/rd/c0d1: RAID-6, Online, 3305472 blocks, Write Thru

  No Rebuild or Consistency Check in Progress

gwynedd:/u/lnz# cat /proc/rd/status

OK

The above messages indicate that everything is healthy, and /proc/rd/status

returns "OK" indicating that there are no problems with any DAC960 controller

in the system.  For demonstration purposes, while I/O is active Physical Drive

1:1 is now disconnected, simulating a drive failure.  The failure is noted by

the driver within 10 seconds of the controller's having detected it, and the

driver logs the following console status messages indicating that Logical

Drives 0 and 1 are now CRITICAL as a result of Physical Drive 1:1 being DEAD:

DAC960#0: Physical Drive 1:2 Error Log: Sense Key = 6, ASC = 29, ASCQ = 02

DAC960#0: Physical Drive 1:3 Error Log: Sense Key = 6, ASC = 29, ASCQ = 02

DAC960#0: Physical Drive 1:1 killed because of timeout on SCSI command

DAC960#0: Physical Drive 1:1 is now DEAD

DAC960#0: Logical Drive 0 (/dev/rd/c0d0) is now CRITICAL

DAC960#0: Logical Drive 1 (/dev/rd/c0d1) is now CRITICAL

The Sense Keys logged here are just Check Condition / Unit Attention conditions

arising from a SCSI bus reset that is forced by the controller during its error

recovery procedures.  Concurrently with the above, the driver status available

from /proc/rd also reflects the drive failure.  The status message in

/proc/rd/status has changed from "OK" to "ALERT":

gwynedd:/u/lnz# cat /proc/rd/status

ALERT

and /proc/rd/c0/current_status has been updated:

gwynedd:/u/lnz# cat /proc/rd/c0/current_status

  ...

  Physical Devices:

    0:1 - Disk: Online, 2201600 blocks

    0:2 - Disk: Online, 2201600 blocks

    0:3 - Disk: Online, 2201600 blocks

    1:1 - Disk: Dead, 2201600 blocks

    1:2 - Disk: Online, 2201600 blocks

    1:3 - Disk: Online, 2201600 blocks

  Logical Drives:

    /dev/rd/c0d0: RAID-5, Critical, 5498880 blocks, Write Thru

    /dev/rd/c0d1: RAID-6, Critical, 3305472 blocks, Write Thru

  No Rebuild or Consistency Check in Progress

Since there are no standby drives configured, the system can continue to access

the logical drives in a performance degraded mode until the failed drive is

replaced and a rebuild operation completed to restore the redundancy of the

logical drives.  Once Physical Drive 1:1 is replaced with a properly

functioning drive, or if the physical drive was killed without having failed

(e.g., due to electrical problems on the SCSI bus), the user can instruct the

controller to initiate a rebuild operation onto the newly replaced drive:

gwynedd:/u/lnz# echo "rebuild 1:1" > /proc/rd/c0/user_command

gwynedd:/u/lnz# cat /proc/rd/c0/user_command

Rebuild of Physical Drive 1:1 Initiated

The echo command instructs the controller to initiate an asynchronous rebuild

operation onto Physical Drive 1:1, and the status message that results from the

operation is then available for reading from /proc/rd/c0/user_command, as well

as being logged to the console by the driver.

Within 10 seconds of this command the driver logs the initiation of the

asynchronous rebuild operation:

DAC960#0: Rebuild of Physical Drive 1:1 Initiated

DAC960#0: Physical Drive 1:1 Error Log: Sense Key = 6, ASC = 29, ASCQ = 01

DAC960#0: Physical Drive 1:1 is now WRITE-ONLY

DAC960#0: Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 1% completed

and /proc/rd/c0/current_status is updated:

gwynedd:/u/lnz# cat /proc/rd/c0/current_status

  ...

  Physical Devices:

    0:1 - Disk: Online, 2201600 blocks

    0:2 - Disk: Online, 2201600 blocks

    0:3 - Disk: Online, 2201600 blocks

    1:1 - Disk: Write-Only, 2201600 blocks

    1:2 - Disk: Online, 2201600 blocks

    1:3 - Disk: Online, 2201600 blocks

  Logical Drives:

    /dev/rd/c0d0: RAID-5, Critical, 5498880 blocks, Write Thru

    /dev/rd/c0d1: RAID-6, Critical, 3305472 blocks, Write Thru

  Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 6% completed

As the rebuild progresses, the current status in /proc/rd/c0/current_status is

updated every 10 seconds:

gwynedd:/u/lnz# cat /proc/rd/c0/current_status

  ...

  Physical Devices:

    0:1 - Disk: Online, 2201600 blocks

    0:2 - Disk: Online, 2201600 blocks

    0:3 - Disk: Online, 2201600 blocks

    1:1 - Disk: Write-Only, 2201600 blocks

    1:2 - Disk: Online, 2201600 blocks

    1:3 - Disk: Online, 2201600 blocks

  Logical Drives:

    /dev/rd/c0d0: RAID-5, Critical, 5498880 blocks, Write Thru

    /dev/rd/c0d1: RAID-6, Critical, 3305472 blocks, Write Thru

  Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 15% completed

and every minute a progress message is logged to the console by the driver:

DAC960#0: Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 32% completed

DAC960#0: Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 63% completed

DAC960#0: Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 94% completed

DAC960#0: Rebuild in Progress: Logical Drive 1 (/dev/rd/c0d1) 94% completed

Finally, the rebuild completes successfully.  The driver logs the status of the

logical and physical drives and the rebuild completion:

DAC960#0: Rebuild Completed Successfully

DAC960#0: Physical Drive 1:1 is now ONLINE

DAC960#0: Logical Drive 0 (/dev/rd/c0d0) is now ONLINE

DAC960#0: Logical Drive 1 (/dev/rd/c0d1) is now ONLINE

/proc/rd/c0/current_status is updated:

gwynedd:/u/lnz# cat /proc/rd/c0/current_status

  ...

  Physical Devices:

    0:1 - Disk: Online, 2201600 blocks

    0:2 - Disk: Online, 2201600 blocks

    0:3 - Disk: Online, 2201600 blocks

    1:1 - Disk: Online, 2201600 blocks

    1:2 - Disk: Online, 2201600 blocks

    1:3 - Disk: Online, 2201600 blocks

  Logical Drives:

    /dev/rd/c0d0: RAID-5, Online, 5498880 blocks, Write Thru

    /dev/rd/c0d1: RAID-6, Online, 3305472 blocks, Write Thru

  Rebuild Completed Successfully

and /proc/rd/status indicates that everything is healthy once again:

gwynedd:/u/lnz# cat /proc/rd/status

OK

                EXAMPLE II - DRIVE FAILURE WITH A STANDBY DRIVE

The following annotated logs demonstrate the controller configuration and and

online status monitoring capabilities of the Linux DAC960 Driver.  The test

configuration comprises 6 1GB Quantum Atlas I disk drives on two channels of a

DAC960PJ controller.  The physical drives are configured into a single drive

group with a standby drive, and the drive group has been configured into two

logical drives, one RAID-5 and one RAID-6.  Note that these logs are from an

earlier version of the driver and the messages have changed somewhat with newer

releases, but the functionality remains similar.  First, here is the current

status of the RAID configuration:

gwynedd:/u/lnz# cat /proc/rd/c0/current_status

***** DAC960 RAID Driver Version 2.0.0 of 23 March 1999 *****

Copyright 1998-1999 by Leonard N. Zubkoff 

Configuring Mylex DAC960PJ PCI RAID Controller

  Firmware Version: 4.06-0-08, Channels: 3, Memory Size: 8MB

  PCI Bus: 0, Device: 19, Function: 1, I/O Address: Unassigned

  PCI Address: 0xFD4FC000 mapped at 0x8807000, IRQ Channel: 9

  Controller Queue Depth: 128, Maximum Blocks per Command: 128

  Driver Queue Depth: 127, Maximum Scatter/Gather Segments: 33

  Stripe Size: 64KB, Segment Size: 8KB, BIOS Geometry: 255/63

  Physical Devices:

    0:1 - Disk: Online, 2201600 blocks

    0:2 - Disk: Online, 2201600 blocks

    0:3 - Disk: Online, 2201600 blocks

    1:1 - Disk: Online, 2201600 blocks

    1:2 - Disk: Online, 2201600 blocks

    1:3 - Disk: Standby, 2201600 blocks

  Logical Drives:

    /dev/rd/c0d0: RAID-5, Online, 4399104 blocks, Write Thru

    /dev/rd/c0d1: RAID-6, Online, 2754560 blocks, Write Thru

  No Rebuild or Consistency Check in Progress

gwynedd:/u/lnz# cat /proc/rd/status

OK

The above messages indicate that everything is healthy, and /proc/rd/status

returns "OK" indicating that there are no problems with any DAC960 controller

in the system.  For demonstration purposes, while I/O is active Physical Drive

1:2 is now disconnected, simulating a drive failure.  The failure is noted by

the driver within 10 seconds of the controller's having detected it, and the

driver logs the following console status messages:

DAC960#0: Physical Drive 1:1 Error Log: Sense Key = 6, ASC = 29, ASCQ = 02

DAC960#0: Physical Drive 1:3 Error Log: Sense Key = 6, ASC = 29, ASCQ = 02

DAC960#0: Physical Drive 1:2 killed because of timeout on SCSI command

DAC960#0: Physical Drive 1:2 is now DEAD

DAC960#0: Physical Drive 1:2 killed because it was removed

DAC960#0: Logical Drive 0 (/dev/rd/c0d0) is now CRITICAL

DAC960#0: Logical Drive 1 (/dev/rd/c0d1) is now CRITICAL

Since a standby drive is configured, the controller automatically begins

rebuilding onto the standby drive:

DAC960#0: Physical Drive 1:3 is now WRITE-ONLY

DAC960#0: Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 4% completed

Concurrently with the above, the driver status available from /proc/rd also

reflects the drive failure and automatic rebuild.  The status message in

/proc/rd/status has changed from "OK" to "ALERT":

gwynedd:/u/lnz# cat /proc/rd/status

ALERT

and /proc/rd/c0/current_status has been updated:

gwynedd:/u/lnz# cat /proc/rd/c0/current_status

  ...

  Physical Devices:

    0:1 - Disk: Online, 2201600 blocks

    0:2 - Disk: Online, 2201600 blocks

    0:3 - Disk: Online, 2201600 blocks

    1:1 - Disk: Online, 2201600 blocks

    1:2 - Disk: Dead, 2201600 blocks

    1:3 - Disk: Write-Only, 2201600 blocks

  Logical Drives:

    /dev/rd/c0d0: RAID-5, Critical, 4399104 blocks, Write Thru

    /dev/rd/c0d1: RAID-6, Critical, 2754560 blocks, Write Thru

  Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 4% completed

As the rebuild progresses, the current status in /proc/rd/c0/current_status is

updated every 10 seconds:

gwynedd:/u/lnz# cat /proc/rd/c0/current_status

  ...

  Physical Devices:

    0:1 - Disk: Online, 2201600 blocks

    0:2 - Disk: Online, 2201600 blocks

    0:3 - Disk: Online, 2201600 blocks

    1:1 - Disk: Online, 2201600 blocks

    1:2 - Disk: Dead, 2201600 blocks

    1:3 - Disk: Write-Only, 2201600 blocks

  Logical Drives:

    /dev/rd/c0d0: RAID-5, Critical, 4399104 blocks, Write Thru

    /dev/rd/c0d1: RAID-6, Critical, 2754560 blocks, Write Thru

  Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 40% completed

and every minute a progress message is logged on the console by the driver:

DAC960#0: Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 40% completed

DAC960#0: Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 76% completed

DAC960#0: Rebuild in Progress: Logical Drive 1 (/dev/rd/c0d1) 66% completed

DAC960#0: Rebuild in Progress: Logical Drive 1 (/dev/rd/c0d1) 84% completed

Finally, the rebuild completes successfully.  The driver logs the status of the

logical and physical drives and the rebuild completion:

DAC960#0: Rebuild Completed Successfully

DAC960#0: Physical Drive 1:3 is now ONLINE

DAC960#0: Logical Drive 0 (/dev/rd/c0d0) is now ONLINE

DAC960#0: Logical Drive 1 (/dev/rd/c0d1) is now ONLINE

/proc/rd/c0/current_status is updated:

***** DAC960 RAID Driver Version 2.0.0 of 23 March 1999 *****

Copyright 1998-1999 by Leonard N. Zubkoff 

Configuring Mylex DAC960PJ PCI RAID Controller

  Firmware Version: 4.06-0-08, Channels: 3, Memory Size: 8MB

  PCI Bus: 0, Device: 19, Function: 1, I/O Address: Unassigned

  PCI Address: 0xFD4FC000 mapped at 0x8807000, IRQ Channel: 9

  Controller Queue Depth: 128, Maximum Blocks per Command: 128

  Driver Queue Depth: 127, Maximum Scatter/Gather Segments: 33

  Stripe Size: 64KB, Segment Size: 8KB, BIOS Geometry: 255/63

  Physical Devices:

    0:1 - Disk: Online, 2201600 blocks

    0:2 - Disk: Online, 2201600 blocks

    0:3 - Disk: Online, 2201600 blocks

    1:1 - Disk: Online, 2201600 blocks

    1:2 - Disk: Dead, 2201600 blocks

    1:3 - Disk: Online, 2201600 blocks

  Logical Drives:

    /dev/rd/c0d0: RAID-5, Online, 4399104 blocks, Write Thru

    /dev/rd/c0d1: RAID-6, Online, 2754560 blocks, Write Thru

  Rebuild Completed Successfully

and /proc/rd/status indicates that everything is healthy once again:

gwynedd:/u/lnz# cat /proc/rd/status

OK

Note that the absence of a viable standby drive does not create an "ALERT"

status.  Once dead Physical Drive 1:2 has been replaced, the controller must be

told that this has occurred and that the newly replaced drive should become the

new standby drive:

gwynedd:/u/lnz# echo "make-standby 1:2" > /proc/rd/c0/user_command

gwynedd:/u/lnz# cat /proc/rd/c0/user_command

Make Standby of Physical Drive 1:2 Succeeded

The echo command instructs the controller to make Physical Drive 1:2 into a

standby drive, and the status message that results from the operation is then

available for reading from /proc/rd/c0/user_command, as well as being logged to

the console by the driver.  Within 60 seconds of this command the driver logs:

DAC960#0: Physical Drive 1:2 Error Log: Sense Key = 6, ASC = 29, ASCQ = 01

DAC960#0: Physical Drive 1:2 is now STANDBY

DAC960#0: Make Standby of Physical Drive 1:2 Succeeded

and /proc/rd/c0/current_status is updated:

gwynedd:/u/lnz# cat /proc/rd/c0/current_status

  ...

  Physical Devices:

    0:1 - Disk: Online, 2201600 blocks

    0:2 - Disk: Online, 2201600 blocks

    0:3 - Disk: Online, 2201600 blocks

    1:1 - Disk: Online, 2201600 blocks

    1:2 - Disk: Standby, 2201600 blocks

    1:3 - Disk: Online, 2201600 blocks

  Logical Drives:

    /dev/rd/c0d0: RAID-5, Online, 4399104 blocks, Write Thru

    /dev/rd/c0d1: RAID-6, Online, 2754560 blocks, Write Thru

  Rebuild Completed Successfully