Root/Documentation/blockdev/README.DAC960

1   Linux Driver for Mylex DAC960/AcceleRAID/eXtremeRAID PCI RAID Controllers
2
3            Version 2.2.11 for Linux 2.2.19
4            Version 2.4.11 for Linux 2.4.12
5
6                  PRODUCTION RELEASE
7
8                11 October 2001
9
10                   Leonard N. Zubkoff
11                   Dandelion Digital
12                   lnz@dandelion.com
13
14     Copyright 1998-2001 by Leonard N. Zubkoff <lnz@dandelion.com>
15
16
17                 INTRODUCTION
18
19Mylex, Inc. designs and manufactures a variety of high performance PCI RAID
20controllers. Mylex Corporation is located at 34551 Ardenwood Blvd., Fremont,
21California 94555, USA and can be reached at 510.796.6100 or on the World Wide
22Web at http://www.mylex.com. Mylex Technical Support can be reached by
23electronic mail at mylexsup@us.ibm.com, by voice at 510.608.2400, or by FAX at
24510.745.7715. Contact information for offices in Europe and Japan is available
25on their Web site.
26
27The latest information on Linux support for DAC960 PCI RAID Controllers, as
28well as the most recent release of this driver, will always be available from
29my Linux Home Page at URL "http://www.dandelion.com/Linux/". The Linux DAC960
30driver supports all current Mylex PCI RAID controllers including the new
31eXtremeRAID 2000/3000 and AcceleRAID 352/170/160 models which have an entirely
32new firmware interface from the older eXtremeRAID 1100, AcceleRAID 150/200/250,
33and DAC960PJ/PG/PU/PD/PL. See below for a complete controller list as well as
34minimum firmware version requirements. For simplicity, in most places this
35documentation refers to DAC960 generically rather than explicitly listing all
36the supported models.
37
38Driver bug reports should be sent via electronic mail to "lnz@dandelion.com".
39Please include with the bug report the complete configuration messages reported
40by the driver at startup, along with any subsequent system messages relevant to
41the controller's operation, and a detailed description of your system's
42hardware configuration. Driver bugs are actually quite rare; if you encounter
43problems with disks being marked offline, for example, please contact Mylex
44Technical Support as the problem is related to the hardware configuration
45rather than the Linux driver.
46
47Please consult the RAID controller documentation for detailed information
48regarding installation and configuration of the controllers. This document
49primarily provides information specific to the Linux support.
50
51
52                DRIVER FEATURES
53
54The DAC960 RAID controllers are supported solely as high performance RAID
55controllers, not as interfaces to arbitrary SCSI devices. The Linux DAC960
56driver operates at the block device level, the same level as the SCSI and IDE
57drivers. Unlike other RAID controllers currently supported on Linux, the
58DAC960 driver is not dependent on the SCSI subsystem, and hence avoids all the
59complexity and unnecessary code that would be associated with an implementation
60as a SCSI driver. The DAC960 driver is designed for as high a performance as
61possible with no compromises or extra code for compatibility with lower
62performance devices. The DAC960 driver includes extensive error logging and
63online configuration management capabilities. Except for initial configuration
64of the controller and adding new disk drives, most everything can be handled
65from Linux while the system is operational.
66
67The DAC960 driver is architected to support up to 8 controllers per system.
68Each DAC960 parallel SCSI controller can support up to 15 disk drives per
69channel, for a maximum of 60 drives on a four channel controller; the fibre
70channel eXtremeRAID 3000 controller supports up to 125 disk drives per loop for
71a total of 250 drives. The drives installed on a controller are divided into
72one or more "Drive Groups", and then each Drive Group is subdivided further
73into 1 to 32 "Logical Drives". Each Logical Drive has a specific RAID Level
74and caching policy associated with it, and it appears to Linux as a single
75block device. Logical Drives are further subdivided into up to 7 partitions
76through the normal Linux and PC disk partitioning schemes. Logical Drives are
77also known as "System Drives", and Drive Groups are also called "Packs". Both
78terms are in use in the Mylex documentation; I have chosen to standardize on
79the more generic "Logical Drive" and "Drive Group".
80
81DAC960 RAID disk devices are named in the style of the obsolete Device File
82System (DEVFS). The device corresponding to Logical Drive D on Controller C
83is referred to as /dev/rd/cCdD, and the partitions are called /dev/rd/cCdDp1
84through /dev/rd/cCdDp7. For example, partition 3 of Logical Drive 5 on
85Controller 2 is referred to as /dev/rd/c2d5p3. Note that unlike with SCSI
86disks the device names will not change in the event of a disk drive failure.
87The DAC960 driver is assigned major numbers 48 - 55 with one major number per
88controller. The 8 bits of minor number are divided into 5 bits for the Logical
89Drive and 3 bits for the partition.
90
91
92      SUPPORTED DAC960/AcceleRAID/eXtremeRAID PCI RAID CONTROLLERS
93
94The following list comprises the supported DAC960, AcceleRAID, and eXtremeRAID
95PCI RAID Controllers as of the date of this document. It is recommended that
96anyone purchasing a Mylex PCI RAID Controller not in the following table
97contact the author beforehand to verify that it is or will be supported.
98
99eXtremeRAID 3000
100        1 Wide Ultra-2/LVD SCSI channel
101        2 External Fibre FC-AL channels
102        233MHz StrongARM SA 110 Processor
103        64 Bit 33MHz PCI (backward compatible with 32 Bit PCI slots)
104        32MB/64MB ECC SDRAM Memory
105
106eXtremeRAID 2000
107        4 Wide Ultra-160 LVD SCSI channels
108        233MHz StrongARM SA 110 Processor
109        64 Bit 33MHz PCI (backward compatible with 32 Bit PCI slots)
110        32MB/64MB ECC SDRAM Memory
111
112AcceleRAID 352
113        2 Wide Ultra-160 LVD SCSI channels
114        100MHz Intel i960RN RISC Processor
115        64 Bit 33MHz PCI (backward compatible with 32 Bit PCI slots)
116        32MB/64MB ECC SDRAM Memory
117
118AcceleRAID 170
119        1 Wide Ultra-160 LVD SCSI channel
120        100MHz Intel i960RM RISC Processor
121        16MB/32MB/64MB ECC SDRAM Memory
122
123AcceleRAID 160 (AcceleRAID 170LP)
124        1 Wide Ultra-160 LVD SCSI channel
125        100MHz Intel i960RS RISC Processor
126        Built in 16M ECC SDRAM Memory
127        PCI Low Profile Form Factor - fit for 2U height
128
129eXtremeRAID 1100 (DAC1164P)
130        3 Wide Ultra-2/LVD SCSI channels
131        233MHz StrongARM SA 110 Processor
132        64 Bit 33MHz PCI (backward compatible with 32 Bit PCI slots)
133        16MB/32MB/64MB Parity SDRAM Memory with Battery Backup
134
135AcceleRAID 250 (DAC960PTL1)
136        Uses onboard Symbios SCSI chips on certain motherboards
137        Also includes one onboard Wide Ultra-2/LVD SCSI Channel
138        66MHz Intel i960RD RISC Processor
139        4MB/8MB/16MB/32MB/64MB/128MB ECC EDO Memory
140
141AcceleRAID 200 (DAC960PTL0)
142        Uses onboard Symbios SCSI chips on certain motherboards
143        Includes no onboard SCSI Channels
144        66MHz Intel i960RD RISC Processor
145        4MB/8MB/16MB/32MB/64MB/128MB ECC EDO Memory
146
147AcceleRAID 150 (DAC960PRL)
148        Uses onboard Symbios SCSI chips on certain motherboards
149        Also includes one onboard Wide Ultra-2/LVD SCSI Channel
150        33MHz Intel i960RP RISC Processor
151        4MB Parity EDO Memory
152
153DAC960PJ 1/2/3 Wide Ultra SCSI-3 Channels
154        66MHz Intel i960RD RISC Processor
155        4MB/8MB/16MB/32MB/64MB/128MB ECC EDO Memory
156
157DAC960PG 1/2/3 Wide Ultra SCSI-3 Channels
158        33MHz Intel i960RP RISC Processor
159        4MB/8MB ECC EDO Memory
160
161DAC960PU 1/2/3 Wide Ultra SCSI-3 Channels
162        Intel i960CF RISC Processor
163        4MB/8MB EDRAM or 2MB/4MB/8MB/16MB/32MB DRAM Memory
164
165DAC960PD 1/2/3 Wide Fast SCSI-2 Channels
166        Intel i960CF RISC Processor
167        4MB/8MB EDRAM or 2MB/4MB/8MB/16MB/32MB DRAM Memory
168
169DAC960PL 1/2/3 Wide Fast SCSI-2 Channels
170        Intel i960 RISC Processor
171        2MB/4MB/8MB/16MB/32MB DRAM Memory
172
173DAC960P 1/2/3 Wide Fast SCSI-2 Channels
174        Intel i960 RISC Processor
175        2MB/4MB/8MB/16MB/32MB DRAM Memory
176
177For the eXtremeRAID 2000/3000 and AcceleRAID 352/170/160, firmware version
1786.00-01 or above is required.
179
180For the eXtremeRAID 1100, firmware version 5.06-0-52 or above is required.
181
182For the AcceleRAID 250, 200, and 150, firmware version 4.06-0-57 or above is
183required.
184
185For the DAC960PJ and DAC960PG, firmware version 4.06-0-00 or above is required.
186
187For the DAC960PU, DAC960PD, DAC960PL, and DAC960P, either firmware version
1883.51-0-04 or above is required (for dual Flash ROM controllers), or firmware
189version 2.73-0-00 or above is required (for single Flash ROM controllers)
190
191Please note that not all SCSI disk drives are suitable for use with DAC960
192controllers, and only particular firmware versions of any given model may
193actually function correctly. Similarly, not all motherboards have a BIOS that
194properly initializes the AcceleRAID 250, AcceleRAID 200, AcceleRAID 150,
195DAC960PJ, and DAC960PG because the Intel i960RD/RP is a multi-function device.
196If in doubt, contact Mylex RAID Technical Support (mylexsup@us.ibm.com) to
197verify compatibility. Mylex makes available a hard disk compatibility list at
198http://www.mylex.com/support/hdcomp/hd-lists.html.
199
200
201                  DRIVER INSTALLATION
202
203This distribution was prepared for Linux kernel version 2.2.19 or 2.4.12.
204
205To install the DAC960 RAID driver, you may use the following commands,
206replacing "/usr/src" with wherever you keep your Linux kernel source tree:
207
208  cd /usr/src
209  tar -xvzf DAC960-2.2.11.tar.gz (or DAC960-2.4.11.tar.gz)
210  mv README.DAC960 linux/Documentation
211  mv DAC960.[ch] linux/drivers/block
212  patch -p0 < DAC960.patch (if DAC960.patch is included)
213  cd linux
214  make config
215  make bzImage (or zImage)
216
217Then install "arch/x86/boot/bzImage" or "arch/x86/boot/zImage" as your
218standard kernel, run lilo if appropriate, and reboot.
219
220To create the necessary devices in /dev, the "make_rd" script included in
221"DAC960-Utilities.tar.gz" from http://www.dandelion.com/Linux/ may be used.
222LILO 21 and FDISK v2.9 include DAC960 support; also included in this archive
223are patches to LILO 20 and FDISK v2.8 that add DAC960 support, along with
224statically linked executables of LILO and FDISK. This modified version of LILO
225will allow booting from a DAC960 controller and/or mounting the root file
226system from a DAC960.
227
228Red Hat Linux 6.0 and SuSE Linux 6.1 include support for Mylex PCI RAID
229controllers. Installing directly onto a DAC960 may be problematic from other
230Linux distributions until their installation utilities are updated.
231
232
233                  INSTALLATION NOTES
234
235Before installing Linux or adding DAC960 logical drives to an existing Linux
236system, the controller must first be configured to provide one or more logical
237drives using the BIOS Configuration Utility or DACCF. Please note that since
238there are only at most 6 usable partitions on each logical drive, systems
239requiring more partitions should subdivide a drive group into multiple logical
240drives, each of which can have up to 6 usable partitions. Also, note that with
241large disk arrays it is advisable to enable the 8GB BIOS Geometry (255/63)
242rather than accepting the default 2GB BIOS Geometry (128/32); failing to so do
243will cause the logical drive geometry to have more than 65535 cylinders which
244will make it impossible for FDISK to be used properly. The 8GB BIOS Geometry
245can be enabled by configuring the DAC960 BIOS, which is accessible via Alt-M
246during the BIOS initialization sequence.
247
248For maximum performance and the most efficient E2FSCK performance, it is
249recommended that EXT2 file systems be built with a 4KB block size and 16 block
250stride to match the DAC960 controller's 64KB default stripe size. The command
251"mke2fs -b 4096 -R stride=16 <device>" is appropriate. Unless there will be a
252large number of small files on the file systems, it is also beneficial to add
253the "-i 16384" option to increase the bytes per inode parameter thereby
254reducing the file system metadata. Finally, on systems that will only be run
255with Linux 2.2 or later kernels it is beneficial to enable sparse superblocks
256with the "-s 1" option.
257
258
259              DAC960 ANNOUNCEMENTS MAILING LIST
260
261The DAC960 Announcements Mailing List provides a forum for informing Linux
262users of new driver releases and other announcements regarding Linux support
263for DAC960 PCI RAID Controllers. To join the mailing list, send a message to
264"dac960-announce-request@dandelion.com" with the line "subscribe" in the
265message body.
266
267
268        CONTROLLER CONFIGURATION AND STATUS MONITORING
269
270The DAC960 RAID controllers running firmware 4.06 or above include a Background
271Initialization facility so that system downtime is minimized both for initial
272installation and subsequent configuration of additional storage. The BIOS
273Configuration Utility (accessible via Alt-R during the BIOS initialization
274sequence) is used to quickly configure the controller, and then the logical
275drives that have been created are available for immediate use even while they
276are still being initialized by the controller. The primary need for online
277configuration and status monitoring is then to avoid system downtime when disk
278drives fail and must be replaced. Mylex's online monitoring and configuration
279utilities are being ported to Linux and will become available at some point in
280the future. Note that with a SAF-TE (SCSI Accessed Fault-Tolerant Enclosure)
281enclosure, the controller is able to rebuild failed drives automatically as
282soon as a drive replacement is made available.
283
284The primary interfaces for controller configuration and status monitoring are
285special files created in the /proc/rd/... hierarchy along with the normal
286system console logging mechanism. Whenever the system is operating, the DAC960
287driver queries each controller for status information every 10 seconds, and
288checks for additional conditions every 60 seconds. The initial status of each
289controller is always available for controller N in /proc/rd/cN/initial_status,
290and the current status as of the last status monitoring query is available in
291/proc/rd/cN/current_status. In addition, status changes are also logged by the
292driver to the system console and will appear in the log files maintained by
293syslog. The progress of asynchronous rebuild or consistency check operations
294is also available in /proc/rd/cN/current_status, and progress messages are
295logged to the system console at most every 60 seconds.
296
297Starting with the 2.2.3/2.0.3 versions of the driver, the status information
298available in /proc/rd/cN/initial_status and /proc/rd/cN/current_status has been
299augmented to include the vendor, model, revision, and serial number (if
300available) for each physical device found connected to the controller:
301
302***** DAC960 RAID Driver Version 2.2.3 of 19 August 1999 *****
303Copyright 1998-1999 by Leonard N. Zubkoff <lnz@dandelion.com>
304Configuring Mylex DAC960PRL PCI RAID Controller
305  Firmware Version: 4.07-0-07, Channels: 1, Memory Size: 16MB
306  PCI Bus: 1, Device: 4, Function: 1, I/O Address: Unassigned
307  PCI Address: 0xFE300000 mapped at 0xA0800000, IRQ Channel: 21
308  Controller Queue Depth: 128, Maximum Blocks per Command: 128
309  Driver Queue Depth: 127, Maximum Scatter/Gather Segments: 33
310  Stripe Size: 64KB, Segment Size: 8KB, BIOS Geometry: 255/63
311  SAF-TE Enclosure Management Enabled
312  Physical Devices:
313    0:0 Vendor: IBM Model: DRVS09D Revision: 0270
314         Serial Number: 68016775HA
315         Disk Status: Online, 17928192 blocks
316    0:1 Vendor: IBM Model: DRVS09D Revision: 0270
317         Serial Number: 68004E53HA
318         Disk Status: Online, 17928192 blocks
319    0:2 Vendor: IBM Model: DRVS09D Revision: 0270
320         Serial Number: 13013935HA
321         Disk Status: Online, 17928192 blocks
322    0:3 Vendor: IBM Model: DRVS09D Revision: 0270
323         Serial Number: 13016897HA
324         Disk Status: Online, 17928192 blocks
325    0:4 Vendor: IBM Model: DRVS09D Revision: 0270
326         Serial Number: 68019905HA
327         Disk Status: Online, 17928192 blocks
328    0:5 Vendor: IBM Model: DRVS09D Revision: 0270
329         Serial Number: 68012753HA
330         Disk Status: Online, 17928192 blocks
331    0:6 Vendor: ESG-SHV Model: SCA HSBP M6 Revision: 0.61
332  Logical Drives:
333    /dev/rd/c0d0: RAID-5, Online, 89640960 blocks, Write Thru
334  No Rebuild or Consistency Check in Progress
335
336To simplify the monitoring process for custom software, the special file
337/proc/rd/status returns "OK" when all DAC960 controllers in the system are
338operating normally and no failures have occurred, or "ALERT" if any logical
339drives are offline or critical or any non-standby physical drives are dead.
340
341Configuration commands for controller N are available via the special file
342/proc/rd/cN/user_command. A human readable command can be written to this
343special file to initiate a configuration operation, and the results of the
344operation can then be read back from the special file in addition to being
345logged to the system console. The shell command sequence
346
347  echo "<configuration-command>" > /proc/rd/c0/user_command
348  cat /proc/rd/c0/user_command
349
350is typically used to execute configuration commands. The configuration
351commands are:
352
353  flush-cache
354
355    The "flush-cache" command flushes the controller's cache. The system
356    automatically flushes the cache at shutdown or if the driver module is
357    unloaded, so this command is only needed to be certain a write back cache
358    is flushed to disk before the system is powered off by a command to a UPS.
359    Note that the flush-cache command also stops an asynchronous rebuild or
360    consistency check, so it should not be used except when the system is being
361    halted.
362
363  kill <channel>:<target-id>
364
365    The "kill" command marks the physical drive <channel>:<target-id> as DEAD.
366    This command is provided primarily for testing, and should not be used
367    during normal system operation.
368
369  make-online <channel>:<target-id>
370
371    The "make-online" command changes the physical drive <channel>:<target-id>
372    from status DEAD to status ONLINE. In cases where multiple physical drives
373    have been killed simultaneously, this command may be used to bring all but
374    one of them back online, after which a rebuild to the final drive is
375    necessary.
376
377    Warning: make-online should only be used on a dead physical drive that is
378    an active part of a drive group, never on a standby drive. The command
379    should never be used on a dead drive that is part of a critical logical
380    drive; rebuild should be used if only a single drive is dead.
381
382  make-standby <channel>:<target-id>
383
384    The "make-standby" command changes physical drive <channel>:<target-id>
385    from status DEAD to status STANDBY. It should only be used in cases where
386    a dead drive was replaced after an automatic rebuild was performed onto a
387    standby drive. It cannot be used to add a standby drive to the controller
388    configuration if one was not created initially; the BIOS Configuration
389    Utility must be used for that currently.
390
391  rebuild <channel>:<target-id>
392
393    The "rebuild" command initiates an asynchronous rebuild onto physical drive
394    <channel>:<target-id>. It should only be used when a dead drive has been
395    replaced.
396
397  check-consistency <logical-drive-number>
398
399    The "check-consistency" command initiates an asynchronous consistency check
400    of <logical-drive-number> with automatic restoration. It can be used
401    whenever it is desired to verify the consistency of the redundancy
402    information.
403
404  cancel-rebuild
405  cancel-consistency-check
406
407    The "cancel-rebuild" and "cancel-consistency-check" commands cancel any
408    rebuild or consistency check operations previously initiated.
409
410
411           EXAMPLE I - DRIVE FAILURE WITHOUT A STANDBY DRIVE
412
413The following annotated logs demonstrate the controller configuration and and
414online status monitoring capabilities of the Linux DAC960 Driver. The test
415configuration comprises 6 1GB Quantum Atlas I disk drives on two channels of a
416DAC960PJ controller. The physical drives are configured into a single drive
417group without a standby drive, and the drive group has been configured into two
418logical drives, one RAID-5 and one RAID-6. Note that these logs are from an
419earlier version of the driver and the messages have changed somewhat with newer
420releases, but the functionality remains similar. First, here is the current
421status of the RAID configuration:
422
423gwynedd:/u/lnz# cat /proc/rd/c0/current_status
424***** DAC960 RAID Driver Version 2.0.0 of 23 March 1999 *****
425Copyright 1998-1999 by Leonard N. Zubkoff <lnz@dandelion.com>
426Configuring Mylex DAC960PJ PCI RAID Controller
427  Firmware Version: 4.06-0-08, Channels: 3, Memory Size: 8MB
428  PCI Bus: 0, Device: 19, Function: 1, I/O Address: Unassigned
429  PCI Address: 0xFD4FC000 mapped at 0x8807000, IRQ Channel: 9
430  Controller Queue Depth: 128, Maximum Blocks per Command: 128
431  Driver Queue Depth: 127, Maximum Scatter/Gather Segments: 33
432  Stripe Size: 64KB, Segment Size: 8KB, BIOS Geometry: 255/63
433  Physical Devices:
434    0:1 - Disk: Online, 2201600 blocks
435    0:2 - Disk: Online, 2201600 blocks
436    0:3 - Disk: Online, 2201600 blocks
437    1:1 - Disk: Online, 2201600 blocks
438    1:2 - Disk: Online, 2201600 blocks
439    1:3 - Disk: Online, 2201600 blocks
440  Logical Drives:
441    /dev/rd/c0d0: RAID-5, Online, 5498880 blocks, Write Thru
442    /dev/rd/c0d1: RAID-6, Online, 3305472 blocks, Write Thru
443  No Rebuild or Consistency Check in Progress
444
445gwynedd:/u/lnz# cat /proc/rd/status
446OK
447
448The above messages indicate that everything is healthy, and /proc/rd/status
449returns "OK" indicating that there are no problems with any DAC960 controller
450in the system. For demonstration purposes, while I/O is active Physical Drive
4511:1 is now disconnected, simulating a drive failure. The failure is noted by
452the driver within 10 seconds of the controller's having detected it, and the
453driver logs the following console status messages indicating that Logical
454Drives 0 and 1 are now CRITICAL as a result of Physical Drive 1:1 being DEAD:
455
456DAC960#0: Physical Drive 1:2 Error Log: Sense Key = 6, ASC = 29, ASCQ = 02
457DAC960#0: Physical Drive 1:3 Error Log: Sense Key = 6, ASC = 29, ASCQ = 02
458DAC960#0: Physical Drive 1:1 killed because of timeout on SCSI command
459DAC960#0: Physical Drive 1:1 is now DEAD
460DAC960#0: Logical Drive 0 (/dev/rd/c0d0) is now CRITICAL
461DAC960#0: Logical Drive 1 (/dev/rd/c0d1) is now CRITICAL
462
463The Sense Keys logged here are just Check Condition / Unit Attention conditions
464arising from a SCSI bus reset that is forced by the controller during its error
465recovery procedures. Concurrently with the above, the driver status available
466from /proc/rd also reflects the drive failure. The status message in
467/proc/rd/status has changed from "OK" to "ALERT":
468
469gwynedd:/u/lnz# cat /proc/rd/status
470ALERT
471
472and /proc/rd/c0/current_status has been updated:
473
474gwynedd:/u/lnz# cat /proc/rd/c0/current_status
475  ...
476  Physical Devices:
477    0:1 - Disk: Online, 2201600 blocks
478    0:2 - Disk: Online, 2201600 blocks
479    0:3 - Disk: Online, 2201600 blocks
480    1:1 - Disk: Dead, 2201600 blocks
481    1:2 - Disk: Online, 2201600 blocks
482    1:3 - Disk: Online, 2201600 blocks
483  Logical Drives:
484    /dev/rd/c0d0: RAID-5, Critical, 5498880 blocks, Write Thru
485    /dev/rd/c0d1: RAID-6, Critical, 3305472 blocks, Write Thru
486  No Rebuild or Consistency Check in Progress
487
488Since there are no standby drives configured, the system can continue to access
489the logical drives in a performance degraded mode until the failed drive is
490replaced and a rebuild operation completed to restore the redundancy of the
491logical drives. Once Physical Drive 1:1 is replaced with a properly
492functioning drive, or if the physical drive was killed without having failed
493(e.g., due to electrical problems on the SCSI bus), the user can instruct the
494controller to initiate a rebuild operation onto the newly replaced drive:
495
496gwynedd:/u/lnz# echo "rebuild 1:1" > /proc/rd/c0/user_command
497gwynedd:/u/lnz# cat /proc/rd/c0/user_command
498Rebuild of Physical Drive 1:1 Initiated
499
500The echo command instructs the controller to initiate an asynchronous rebuild
501operation onto Physical Drive 1:1, and the status message that results from the
502operation is then available for reading from /proc/rd/c0/user_command, as well
503as being logged to the console by the driver.
504
505Within 10 seconds of this command the driver logs the initiation of the
506asynchronous rebuild operation:
507
508DAC960#0: Rebuild of Physical Drive 1:1 Initiated
509DAC960#0: Physical Drive 1:1 Error Log: Sense Key = 6, ASC = 29, ASCQ = 01
510DAC960#0: Physical Drive 1:1 is now WRITE-ONLY
511DAC960#0: Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 1% completed
512
513and /proc/rd/c0/current_status is updated:
514
515gwynedd:/u/lnz# cat /proc/rd/c0/current_status
516  ...
517  Physical Devices:
518    0:1 - Disk: Online, 2201600 blocks
519    0:2 - Disk: Online, 2201600 blocks
520    0:3 - Disk: Online, 2201600 blocks
521    1:1 - Disk: Write-Only, 2201600 blocks
522    1:2 - Disk: Online, 2201600 blocks
523    1:3 - Disk: Online, 2201600 blocks
524  Logical Drives:
525    /dev/rd/c0d0: RAID-5, Critical, 5498880 blocks, Write Thru
526    /dev/rd/c0d1: RAID-6, Critical, 3305472 blocks, Write Thru
527  Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 6% completed
528
529As the rebuild progresses, the current status in /proc/rd/c0/current_status is
530updated every 10 seconds:
531
532gwynedd:/u/lnz# cat /proc/rd/c0/current_status
533  ...
534  Physical Devices:
535    0:1 - Disk: Online, 2201600 blocks
536    0:2 - Disk: Online, 2201600 blocks
537    0:3 - Disk: Online, 2201600 blocks
538    1:1 - Disk: Write-Only, 2201600 blocks
539    1:2 - Disk: Online, 2201600 blocks
540    1:3 - Disk: Online, 2201600 blocks
541  Logical Drives:
542    /dev/rd/c0d0: RAID-5, Critical, 5498880 blocks, Write Thru
543    /dev/rd/c0d1: RAID-6, Critical, 3305472 blocks, Write Thru
544  Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 15% completed
545
546and every minute a progress message is logged to the console by the driver:
547
548DAC960#0: Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 32% completed
549DAC960#0: Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 63% completed
550DAC960#0: Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 94% completed
551DAC960#0: Rebuild in Progress: Logical Drive 1 (/dev/rd/c0d1) 94% completed
552
553Finally, the rebuild completes successfully. The driver logs the status of the
554logical and physical drives and the rebuild completion:
555
556DAC960#0: Rebuild Completed Successfully
557DAC960#0: Physical Drive 1:1 is now ONLINE
558DAC960#0: Logical Drive 0 (/dev/rd/c0d0) is now ONLINE
559DAC960#0: Logical Drive 1 (/dev/rd/c0d1) is now ONLINE
560
561/proc/rd/c0/current_status is updated:
562
563gwynedd:/u/lnz# cat /proc/rd/c0/current_status
564  ...
565  Physical Devices:
566    0:1 - Disk: Online, 2201600 blocks
567    0:2 - Disk: Online, 2201600 blocks
568    0:3 - Disk: Online, 2201600 blocks
569    1:1 - Disk: Online, 2201600 blocks
570    1:2 - Disk: Online, 2201600 blocks
571    1:3 - Disk: Online, 2201600 blocks
572  Logical Drives:
573    /dev/rd/c0d0: RAID-5, Online, 5498880 blocks, Write Thru
574    /dev/rd/c0d1: RAID-6, Online, 3305472 blocks, Write Thru
575  Rebuild Completed Successfully
576
577and /proc/rd/status indicates that everything is healthy once again:
578
579gwynedd:/u/lnz# cat /proc/rd/status
580OK
581
582
583        EXAMPLE II - DRIVE FAILURE WITH A STANDBY DRIVE
584
585The following annotated logs demonstrate the controller configuration and and
586online status monitoring capabilities of the Linux DAC960 Driver. The test
587configuration comprises 6 1GB Quantum Atlas I disk drives on two channels of a
588DAC960PJ controller. The physical drives are configured into a single drive
589group with a standby drive, and the drive group has been configured into two
590logical drives, one RAID-5 and one RAID-6. Note that these logs are from an
591earlier version of the driver and the messages have changed somewhat with newer
592releases, but the functionality remains similar. First, here is the current
593status of the RAID configuration:
594
595gwynedd:/u/lnz# cat /proc/rd/c0/current_status
596***** DAC960 RAID Driver Version 2.0.0 of 23 March 1999 *****
597Copyright 1998-1999 by Leonard N. Zubkoff <lnz@dandelion.com>
598Configuring Mylex DAC960PJ PCI RAID Controller
599  Firmware Version: 4.06-0-08, Channels: 3, Memory Size: 8MB
600  PCI Bus: 0, Device: 19, Function: 1, I/O Address: Unassigned
601  PCI Address: 0xFD4FC000 mapped at 0x8807000, IRQ Channel: 9
602  Controller Queue Depth: 128, Maximum Blocks per Command: 128
603  Driver Queue Depth: 127, Maximum Scatter/Gather Segments: 33
604  Stripe Size: 64KB, Segment Size: 8KB, BIOS Geometry: 255/63
605  Physical Devices:
606    0:1 - Disk: Online, 2201600 blocks
607    0:2 - Disk: Online, 2201600 blocks
608    0:3 - Disk: Online, 2201600 blocks
609    1:1 - Disk: Online, 2201600 blocks
610    1:2 - Disk: Online, 2201600 blocks
611    1:3 - Disk: Standby, 2201600 blocks
612  Logical Drives:
613    /dev/rd/c0d0: RAID-5, Online, 4399104 blocks, Write Thru
614    /dev/rd/c0d1: RAID-6, Online, 2754560 blocks, Write Thru
615  No Rebuild or Consistency Check in Progress
616
617gwynedd:/u/lnz# cat /proc/rd/status
618OK
619
620The above messages indicate that everything is healthy, and /proc/rd/status
621returns "OK" indicating that there are no problems with any DAC960 controller
622in the system. For demonstration purposes, while I/O is active Physical Drive
6231:2 is now disconnected, simulating a drive failure. The failure is noted by
624the driver within 10 seconds of the controller's having detected it, and the
625driver logs the following console status messages:
626
627DAC960#0: Physical Drive 1:1 Error Log: Sense Key = 6, ASC = 29, ASCQ = 02
628DAC960#0: Physical Drive 1:3 Error Log: Sense Key = 6, ASC = 29, ASCQ = 02
629DAC960#0: Physical Drive 1:2 killed because of timeout on SCSI command
630DAC960#0: Physical Drive 1:2 is now DEAD
631DAC960#0: Physical Drive 1:2 killed because it was removed
632DAC960#0: Logical Drive 0 (/dev/rd/c0d0) is now CRITICAL
633DAC960#0: Logical Drive 1 (/dev/rd/c0d1) is now CRITICAL
634
635Since a standby drive is configured, the controller automatically begins
636rebuilding onto the standby drive:
637
638DAC960#0: Physical Drive 1:3 is now WRITE-ONLY
639DAC960#0: Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 4% completed
640
641Concurrently with the above, the driver status available from /proc/rd also
642reflects the drive failure and automatic rebuild. The status message in
643/proc/rd/status has changed from "OK" to "ALERT":
644
645gwynedd:/u/lnz# cat /proc/rd/status
646ALERT
647
648and /proc/rd/c0/current_status has been updated:
649
650gwynedd:/u/lnz# cat /proc/rd/c0/current_status
651  ...
652  Physical Devices:
653    0:1 - Disk: Online, 2201600 blocks
654    0:2 - Disk: Online, 2201600 blocks
655    0:3 - Disk: Online, 2201600 blocks
656    1:1 - Disk: Online, 2201600 blocks
657    1:2 - Disk: Dead, 2201600 blocks
658    1:3 - Disk: Write-Only, 2201600 blocks
659  Logical Drives:
660    /dev/rd/c0d0: RAID-5, Critical, 4399104 blocks, Write Thru
661    /dev/rd/c0d1: RAID-6, Critical, 2754560 blocks, Write Thru
662  Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 4% completed
663
664As the rebuild progresses, the current status in /proc/rd/c0/current_status is
665updated every 10 seconds:
666
667gwynedd:/u/lnz# cat /proc/rd/c0/current_status
668  ...
669  Physical Devices:
670    0:1 - Disk: Online, 2201600 blocks
671    0:2 - Disk: Online, 2201600 blocks
672    0:3 - Disk: Online, 2201600 blocks
673    1:1 - Disk: Online, 2201600 blocks
674    1:2 - Disk: Dead, 2201600 blocks
675    1:3 - Disk: Write-Only, 2201600 blocks
676  Logical Drives:
677    /dev/rd/c0d0: RAID-5, Critical, 4399104 blocks, Write Thru
678    /dev/rd/c0d1: RAID-6, Critical, 2754560 blocks, Write Thru
679  Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 40% completed
680
681and every minute a progress message is logged on the console by the driver:
682
683DAC960#0: Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 40% completed
684DAC960#0: Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 76% completed
685DAC960#0: Rebuild in Progress: Logical Drive 1 (/dev/rd/c0d1) 66% completed
686DAC960#0: Rebuild in Progress: Logical Drive 1 (/dev/rd/c0d1) 84% completed
687
688Finally, the rebuild completes successfully. The driver logs the status of the
689logical and physical drives and the rebuild completion:
690
691DAC960#0: Rebuild Completed Successfully
692DAC960#0: Physical Drive 1:3 is now ONLINE
693DAC960#0: Logical Drive 0 (/dev/rd/c0d0) is now ONLINE
694DAC960#0: Logical Drive 1 (/dev/rd/c0d1) is now ONLINE
695
696/proc/rd/c0/current_status is updated:
697
698***** DAC960 RAID Driver Version 2.0.0 of 23 March 1999 *****
699Copyright 1998-1999 by Leonard N. Zubkoff <lnz@dandelion.com>
700Configuring Mylex DAC960PJ PCI RAID Controller
701  Firmware Version: 4.06-0-08, Channels: 3, Memory Size: 8MB
702  PCI Bus: 0, Device: 19, Function: 1, I/O Address: Unassigned
703  PCI Address: 0xFD4FC000 mapped at 0x8807000, IRQ Channel: 9
704  Controller Queue Depth: 128, Maximum Blocks per Command: 128
705  Driver Queue Depth: 127, Maximum Scatter/Gather Segments: 33
706  Stripe Size: 64KB, Segment Size: 8KB, BIOS Geometry: 255/63
707  Physical Devices:
708    0:1 - Disk: Online, 2201600 blocks
709    0:2 - Disk: Online, 2201600 blocks
710    0:3 - Disk: Online, 2201600 blocks
711    1:1 - Disk: Online, 2201600 blocks
712    1:2 - Disk: Dead, 2201600 blocks
713    1:3 - Disk: Online, 2201600 blocks
714  Logical Drives:
715    /dev/rd/c0d0: RAID-5, Online, 4399104 blocks, Write Thru
716    /dev/rd/c0d1: RAID-6, Online, 2754560 blocks, Write Thru
717  Rebuild Completed Successfully
718
719and /proc/rd/status indicates that everything is healthy once again:
720
721gwynedd:/u/lnz# cat /proc/rd/status
722OK
723
724Note that the absence of a viable standby drive does not create an "ALERT"
725status. Once dead Physical Drive 1:2 has been replaced, the controller must be
726told that this has occurred and that the newly replaced drive should become the
727new standby drive:
728
729gwynedd:/u/lnz# echo "make-standby 1:2" > /proc/rd/c0/user_command
730gwynedd:/u/lnz# cat /proc/rd/c0/user_command
731Make Standby of Physical Drive 1:2 Succeeded
732
733The echo command instructs the controller to make Physical Drive 1:2 into a
734standby drive, and the status message that results from the operation is then
735available for reading from /proc/rd/c0/user_command, as well as being logged to
736the console by the driver. Within 60 seconds of this command the driver logs:
737
738DAC960#0: Physical Drive 1:2 Error Log: Sense Key = 6, ASC = 29, ASCQ = 01
739DAC960#0: Physical Drive 1:2 is now STANDBY
740DAC960#0: Make Standby of Physical Drive 1:2 Succeeded
741
742and /proc/rd/c0/current_status is updated:
743
744gwynedd:/u/lnz# cat /proc/rd/c0/current_status
745  ...
746  Physical Devices:
747    0:1 - Disk: Online, 2201600 blocks
748    0:2 - Disk: Online, 2201600 blocks
749    0:3 - Disk: Online, 2201600 blocks
750    1:1 - Disk: Online, 2201600 blocks
751    1:2 - Disk: Standby, 2201600 blocks
752    1:3 - Disk: Online, 2201600 blocks
753  Logical Drives:
754    /dev/rd/c0d0: RAID-5, Online, 4399104 blocks, Write Thru
755    /dev/rd/c0d1: RAID-6, Online, 2754560 blocks, Write Thru
756  Rebuild Completed Successfully
757

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