ia64/linux-2.6.18-xen.hg

view Documentation/README.DAC960 @ 897:329ea0ccb344

balloon: try harder to balloon up under memory pressure.

Currently if the balloon driver is unable to increase the guest's
reservation it assumes the failure was due to reaching its full
allocation, gives up on the ballooning operation and records the limit
it reached as the "hard limit". The driver will not try again until
the target is set again (even to the same value).

However it is possible that ballooning has in fact failed due to
memory pressure in the host and therefore it is desirable to keep
attempting to reach the target in case memory becomes available. The
most likely scenario is that some guests are ballooning down while
others are ballooning up and therefore there is temporary memory
pressure while things stabilise. You would not expect a well behaved
toolstack to ask a domain to balloon to more than its allocation nor
would you expect it to deliberately over-commit memory by setting
balloon targets which exceed the total host memory.

This patch drops the concept of a hard limit and causes the balloon
driver to retry increasing the reservation on a timer in the same
manner as when decreasing the reservation.

Also if we partially succeed in increasing the reservation
(i.e. receive less pages than we asked for) then we may as well keep
those pages rather than returning them to Xen.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
author Keir Fraser <keir.fraser@citrix.com>
date Fri Jun 05 14:01:20 2009 +0100 (2009-06-05)
parents 831230e53067
children
line source
1 Linux Driver for Mylex DAC960/AcceleRAID/eXtremeRAID PCI RAID Controllers
3 Version 2.2.11 for Linux 2.2.19
4 Version 2.4.11 for Linux 2.4.12
6 PRODUCTION RELEASE
8 11 October 2001
10 Leonard N. Zubkoff
11 Dandelion Digital
12 lnz@dandelion.com
14 Copyright 1998-2001 by Leonard N. Zubkoff <lnz@dandelion.com>
17 INTRODUCTION
19 Mylex, Inc. designs and manufactures a variety of high performance PCI RAID
20 controllers. Mylex Corporation is located at 34551 Ardenwood Blvd., Fremont,
21 California 94555, USA and can be reached at 510.796.6100 or on the World Wide
22 Web at http://www.mylex.com. Mylex Technical Support can be reached by
23 electronic mail at mylexsup@us.ibm.com, by voice at 510.608.2400, or by FAX at
24 510.745.7715. Contact information for offices in Europe and Japan is available
25 on their Web site.
27 The latest information on Linux support for DAC960 PCI RAID Controllers, as
28 well as the most recent release of this driver, will always be available from
29 my Linux Home Page at URL "http://www.dandelion.com/Linux/". The Linux DAC960
30 driver supports all current Mylex PCI RAID controllers including the new
31 eXtremeRAID 2000/3000 and AcceleRAID 352/170/160 models which have an entirely
32 new firmware interface from the older eXtremeRAID 1100, AcceleRAID 150/200/250,
33 and DAC960PJ/PG/PU/PD/PL. See below for a complete controller list as well as
34 minimum firmware version requirements. For simplicity, in most places this
35 documentation refers to DAC960 generically rather than explicitly listing all
36 the supported models.
38 Driver bug reports should be sent via electronic mail to "lnz@dandelion.com".
39 Please include with the bug report the complete configuration messages reported
40 by the driver at startup, along with any subsequent system messages relevant to
41 the controller's operation, and a detailed description of your system's
42 hardware configuration. Driver bugs are actually quite rare; if you encounter
43 problems with disks being marked offline, for example, please contact Mylex
44 Technical Support as the problem is related to the hardware configuration
45 rather than the Linux driver.
47 Please consult the RAID controller documentation for detailed information
48 regarding installation and configuration of the controllers. This document
49 primarily provides information specific to the Linux support.
52 DRIVER FEATURES
54 The DAC960 RAID controllers are supported solely as high performance RAID
55 controllers, not as interfaces to arbitrary SCSI devices. The Linux DAC960
56 driver operates at the block device level, the same level as the SCSI and IDE
57 drivers. Unlike other RAID controllers currently supported on Linux, the
58 DAC960 driver is not dependent on the SCSI subsystem, and hence avoids all the
59 complexity and unnecessary code that would be associated with an implementation
60 as a SCSI driver. The DAC960 driver is designed for as high a performance as
61 possible with no compromises or extra code for compatibility with lower
62 performance devices. The DAC960 driver includes extensive error logging and
63 online configuration management capabilities. Except for initial configuration
64 of the controller and adding new disk drives, most everything can be handled
65 from Linux while the system is operational.
67 The DAC960 driver is architected to support up to 8 controllers per system.
68 Each DAC960 parallel SCSI controller can support up to 15 disk drives per
69 channel, for a maximum of 60 drives on a four channel controller; the fibre
70 channel eXtremeRAID 3000 controller supports up to 125 disk drives per loop for
71 a total of 250 drives. The drives installed on a controller are divided into
72 one or more "Drive Groups", and then each Drive Group is subdivided further
73 into 1 to 32 "Logical Drives". Each Logical Drive has a specific RAID Level
74 and caching policy associated with it, and it appears to Linux as a single
75 block device. Logical Drives are further subdivided into up to 7 partitions
76 through the normal Linux and PC disk partitioning schemes. Logical Drives are
77 also known as "System Drives", and Drive Groups are also called "Packs". Both
78 terms are in use in the Mylex documentation; I have chosen to standardize on
79 the more generic "Logical Drive" and "Drive Group".
81 DAC960 RAID disk devices are named in the style of the obsolete Device File
82 System (DEVFS). The device corresponding to Logical Drive D on Controller C
83 is referred to as /dev/rd/cCdD, and the partitions are called /dev/rd/cCdDp1
84 through /dev/rd/cCdDp7. For example, partition 3 of Logical Drive 5 on
85 Controller 2 is referred to as /dev/rd/c2d5p3. Note that unlike with SCSI
86 disks the device names will not change in the event of a disk drive failure.
87 The DAC960 driver is assigned major numbers 48 - 55 with one major number per
88 controller. The 8 bits of minor number are divided into 5 bits for the Logical
89 Drive and 3 bits for the partition.
92 SUPPORTED DAC960/AcceleRAID/eXtremeRAID PCI RAID CONTROLLERS
94 The following list comprises the supported DAC960, AcceleRAID, and eXtremeRAID
95 PCI RAID Controllers as of the date of this document. It is recommended that
96 anyone purchasing a Mylex PCI RAID Controller not in the following table
97 contact the author beforehand to verify that it is or will be supported.
99 eXtremeRAID 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
106 eXtremeRAID 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
112 AcceleRAID 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
118 AcceleRAID 170
119 1 Wide Ultra-160 LVD SCSI channel
120 100MHz Intel i960RM RISC Processor
121 16MB/32MB/64MB ECC SDRAM Memory
123 AcceleRAID 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
129 eXtremeRAID 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
135 AcceleRAID 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
141 AcceleRAID 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
147 AcceleRAID 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
153 DAC960PJ 1/2/3 Wide Ultra SCSI-3 Channels
154 66MHz Intel i960RD RISC Processor
155 4MB/8MB/16MB/32MB/64MB/128MB ECC EDO Memory
157 DAC960PG 1/2/3 Wide Ultra SCSI-3 Channels
158 33MHz Intel i960RP RISC Processor
159 4MB/8MB ECC EDO Memory
161 DAC960PU 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
165 DAC960PD 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
169 DAC960PL 1/2/3 Wide Fast SCSI-2 Channels
170 Intel i960 RISC Processor
171 2MB/4MB/8MB/16MB/32MB DRAM Memory
173 DAC960P 1/2/3 Wide Fast SCSI-2 Channels
174 Intel i960 RISC Processor
175 2MB/4MB/8MB/16MB/32MB DRAM Memory
177 For the eXtremeRAID 2000/3000 and AcceleRAID 352/170/160, firmware version
178 6.00-01 or above is required.
180 For the eXtremeRAID 1100, firmware version 5.06-0-52 or above is required.
182 For the AcceleRAID 250, 200, and 150, firmware version 4.06-0-57 or above is
183 required.
185 For the DAC960PJ and DAC960PG, firmware version 4.06-0-00 or above is required.
187 For the DAC960PU, DAC960PD, DAC960PL, and DAC960P, either firmware version
188 3.51-0-04 or above is required (for dual Flash ROM controllers), or firmware
189 version 2.73-0-00 or above is required (for single Flash ROM controllers)
191 Please note that not all SCSI disk drives are suitable for use with DAC960
192 controllers, and only particular firmware versions of any given model may
193 actually function correctly. Similarly, not all motherboards have a BIOS that
194 properly initializes the AcceleRAID 250, AcceleRAID 200, AcceleRAID 150,
195 DAC960PJ, and DAC960PG because the Intel i960RD/RP is a multi-function device.
196 If in doubt, contact Mylex RAID Technical Support (mylexsup@us.ibm.com) to
197 verify compatibility. Mylex makes available a hard disk compatibility list at
198 http://www.mylex.com/support/hdcomp/hd-lists.html.
201 DRIVER INSTALLATION
203 This distribution was prepared for Linux kernel version 2.2.19 or 2.4.12.
205 To install the DAC960 RAID driver, you may use the following commands,
206 replacing "/usr/src" with wherever you keep your Linux kernel source tree:
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)
217 Then install "arch/i386/boot/bzImage" or "arch/i386/boot/zImage" as your
218 standard kernel, run lilo if appropriate, and reboot.
220 To 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.
222 LILO 21 and FDISK v2.9 include DAC960 support; also included in this archive
223 are patches to LILO 20 and FDISK v2.8 that add DAC960 support, along with
224 statically linked executables of LILO and FDISK. This modified version of LILO
225 will allow booting from a DAC960 controller and/or mounting the root file
226 system from a DAC960.
228 Red Hat Linux 6.0 and SuSE Linux 6.1 include support for Mylex PCI RAID
229 controllers. Installing directly onto a DAC960 may be problematic from other
230 Linux distributions until their installation utilities are updated.
233 INSTALLATION NOTES
235 Before installing Linux or adding DAC960 logical drives to an existing Linux
236 system, the controller must first be configured to provide one or more logical
237 drives using the BIOS Configuration Utility or DACCF. Please note that since
238 there are only at most 6 usable partitions on each logical drive, systems
239 requiring more partitions should subdivide a drive group into multiple logical
240 drives, each of which can have up to 6 usable partitions. Also, note that with
241 large disk arrays it is advisable to enable the 8GB BIOS Geometry (255/63)
242 rather than accepting the default 2GB BIOS Geometry (128/32); failing to so do
243 will cause the logical drive geometry to have more than 65535 cylinders which
244 will make it impossible for FDISK to be used properly. The 8GB BIOS Geometry
245 can be enabled by configuring the DAC960 BIOS, which is accessible via Alt-M
246 during the BIOS initialization sequence.
248 For maximum performance and the most efficient E2FSCK performance, it is
249 recommended that EXT2 file systems be built with a 4KB block size and 16 block
250 stride 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
252 large number of small files on the file systems, it is also beneficial to add
253 the "-i 16384" option to increase the bytes per inode parameter thereby
254 reducing the file system metadata. Finally, on systems that will only be run
255 with Linux 2.2 or later kernels it is beneficial to enable sparse superblocks
256 with the "-s 1" option.
259 DAC960 ANNOUNCEMENTS MAILING LIST
261 The DAC960 Announcements Mailing List provides a forum for informing Linux
262 users of new driver releases and other announcements regarding Linux support
263 for 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
265 message body.
268 CONTROLLER CONFIGURATION AND STATUS MONITORING
270 The DAC960 RAID controllers running firmware 4.06 or above include a Background
271 Initialization facility so that system downtime is minimized both for initial
272 installation and subsequent configuration of additional storage. The BIOS
273 Configuration Utility (accessible via Alt-R during the BIOS initialization
274 sequence) is used to quickly configure the controller, and then the logical
275 drives that have been created are available for immediate use even while they
276 are still being initialized by the controller. The primary need for online
277 configuration and status monitoring is then to avoid system downtime when disk
278 drives fail and must be replaced. Mylex's online monitoring and configuration
279 utilities are being ported to Linux and will become available at some point in
280 the future. Note that with a SAF-TE (SCSI Accessed Fault-Tolerant Enclosure)
281 enclosure, the controller is able to rebuild failed drives automatically as
282 soon as a drive replacement is made available.
284 The primary interfaces for controller configuration and status monitoring are
285 special files created in the /proc/rd/... hierarchy along with the normal
286 system console logging mechanism. Whenever the system is operating, the DAC960
287 driver queries each controller for status information every 10 seconds, and
288 checks for additional conditions every 60 seconds. The initial status of each
289 controller is always available for controller N in /proc/rd/cN/initial_status,
290 and 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
292 driver to the system console and will appear in the log files maintained by
293 syslog. The progress of asynchronous rebuild or consistency check operations
294 is also available in /proc/rd/cN/current_status, and progress messages are
295 logged to the system console at most every 60 seconds.
297 Starting with the 2.2.3/2.0.3 versions of the driver, the status information
298 available in /proc/rd/cN/initial_status and /proc/rd/cN/current_status has been
299 augmented to include the vendor, model, revision, and serial number (if
300 available) for each physical device found connected to the controller:
302 ***** DAC960 RAID Driver Version 2.2.3 of 19 August 1999 *****
303 Copyright 1998-1999 by Leonard N. Zubkoff <lnz@dandelion.com>
304 Configuring 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
336 To simplify the monitoring process for custom software, the special file
337 /proc/rd/status returns "OK" when all DAC960 controllers in the system are
338 operating normally and no failures have occurred, or "ALERT" if any logical
339 drives are offline or critical or any non-standby physical drives are dead.
341 Configuration 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
343 special file to initiate a configuration operation, and the results of the
344 operation can then be read back from the special file in addition to being
345 logged to the system console. The shell command sequence
347 echo "<configuration-command>" > /proc/rd/c0/user_command
348 cat /proc/rd/c0/user_command
350 is typically used to execute configuration commands. The configuration
351 commands are:
353 flush-cache
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.
363 kill <channel>:<target-id>
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.
369 make-online <channel>:<target-id>
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.
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.
382 make-standby <channel>:<target-id>
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.
391 rebuild <channel>:<target-id>
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.
397 check-consistency <logical-drive-number>
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.
404 cancel-rebuild
405 cancel-consistency-check
407 The "cancel-rebuild" and "cancel-consistency-check" commands cancel any
408 rebuild or consistency check operations previously initiated.
411 EXAMPLE I - DRIVE FAILURE WITHOUT A STANDBY DRIVE
413 The following annotated logs demonstrate the controller configuration and and
414 online status monitoring capabilities of the Linux DAC960 Driver. The test
415 configuration comprises 6 1GB Quantum Atlas I disk drives on two channels of a
416 DAC960PJ controller. The physical drives are configured into a single drive
417 group without a standby drive, and the drive group has been configured into two
418 logical drives, one RAID-5 and one RAID-6. Note that these logs are from an
419 earlier version of the driver and the messages have changed somewhat with newer
420 releases, but the functionality remains similar. First, here is the current
421 status of the RAID configuration:
423 gwynedd:/u/lnz# cat /proc/rd/c0/current_status
424 ***** DAC960 RAID Driver Version 2.0.0 of 23 March 1999 *****
425 Copyright 1998-1999 by Leonard N. Zubkoff <lnz@dandelion.com>
426 Configuring 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
445 gwynedd:/u/lnz# cat /proc/rd/status
446 OK
448 The above messages indicate that everything is healthy, and /proc/rd/status
449 returns "OK" indicating that there are no problems with any DAC960 controller
450 in the system. For demonstration purposes, while I/O is active Physical Drive
451 1:1 is now disconnected, simulating a drive failure. The failure is noted by
452 the driver within 10 seconds of the controller's having detected it, and the
453 driver logs the following console status messages indicating that Logical
454 Drives 0 and 1 are now CRITICAL as a result of Physical Drive 1:1 being DEAD:
456 DAC960#0: Physical Drive 1:2 Error Log: Sense Key = 6, ASC = 29, ASCQ = 02
457 DAC960#0: Physical Drive 1:3 Error Log: Sense Key = 6, ASC = 29, ASCQ = 02
458 DAC960#0: Physical Drive 1:1 killed because of timeout on SCSI command
459 DAC960#0: Physical Drive 1:1 is now DEAD
460 DAC960#0: Logical Drive 0 (/dev/rd/c0d0) is now CRITICAL
461 DAC960#0: Logical Drive 1 (/dev/rd/c0d1) is now CRITICAL
463 The Sense Keys logged here are just Check Condition / Unit Attention conditions
464 arising from a SCSI bus reset that is forced by the controller during its error
465 recovery procedures. Concurrently with the above, the driver status available
466 from /proc/rd also reflects the drive failure. The status message in
467 /proc/rd/status has changed from "OK" to "ALERT":
469 gwynedd:/u/lnz# cat /proc/rd/status
470 ALERT
472 and /proc/rd/c0/current_status has been updated:
474 gwynedd:/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
488 Since there are no standby drives configured, the system can continue to access
489 the logical drives in a performance degraded mode until the failed drive is
490 replaced and a rebuild operation completed to restore the redundancy of the
491 logical drives. Once Physical Drive 1:1 is replaced with a properly
492 functioning 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
494 controller to initiate a rebuild operation onto the newly replaced drive:
496 gwynedd:/u/lnz# echo "rebuild 1:1" > /proc/rd/c0/user_command
497 gwynedd:/u/lnz# cat /proc/rd/c0/user_command
498 Rebuild of Physical Drive 1:1 Initiated
500 The echo command instructs the controller to initiate an asynchronous rebuild
501 operation onto Physical Drive 1:1, and the status message that results from the
502 operation is then available for reading from /proc/rd/c0/user_command, as well
503 as being logged to the console by the driver.
505 Within 10 seconds of this command the driver logs the initiation of the
506 asynchronous rebuild operation:
508 DAC960#0: Rebuild of Physical Drive 1:1 Initiated
509 DAC960#0: Physical Drive 1:1 Error Log: Sense Key = 6, ASC = 29, ASCQ = 01
510 DAC960#0: Physical Drive 1:1 is now WRITE-ONLY
511 DAC960#0: Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 1% completed
513 and /proc/rd/c0/current_status is updated:
515 gwynedd:/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
529 As the rebuild progresses, the current status in /proc/rd/c0/current_status is
530 updated every 10 seconds:
532 gwynedd:/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
546 and every minute a progress message is logged to the console by the driver:
548 DAC960#0: Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 32% completed
549 DAC960#0: Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 63% completed
550 DAC960#0: Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 94% completed
551 DAC960#0: Rebuild in Progress: Logical Drive 1 (/dev/rd/c0d1) 94% completed
553 Finally, the rebuild completes successfully. The driver logs the status of the
554 logical and physical drives and the rebuild completion:
556 DAC960#0: Rebuild Completed Successfully
557 DAC960#0: Physical Drive 1:1 is now ONLINE
558 DAC960#0: Logical Drive 0 (/dev/rd/c0d0) is now ONLINE
559 DAC960#0: Logical Drive 1 (/dev/rd/c0d1) is now ONLINE
561 /proc/rd/c0/current_status is updated:
563 gwynedd:/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
577 and /proc/rd/status indicates that everything is healthy once again:
579 gwynedd:/u/lnz# cat /proc/rd/status
580 OK
583 EXAMPLE II - DRIVE FAILURE WITH A STANDBY DRIVE
585 The following annotated logs demonstrate the controller configuration and and
586 online status monitoring capabilities of the Linux DAC960 Driver. The test
587 configuration comprises 6 1GB Quantum Atlas I disk drives on two channels of a
588 DAC960PJ controller. The physical drives are configured into a single drive
589 group with a standby drive, and the drive group has been configured into two
590 logical drives, one RAID-5 and one RAID-6. Note that these logs are from an
591 earlier version of the driver and the messages have changed somewhat with newer
592 releases, but the functionality remains similar. First, here is the current
593 status of the RAID configuration:
595 gwynedd:/u/lnz# cat /proc/rd/c0/current_status
596 ***** DAC960 RAID Driver Version 2.0.0 of 23 March 1999 *****
597 Copyright 1998-1999 by Leonard N. Zubkoff <lnz@dandelion.com>
598 Configuring 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
617 gwynedd:/u/lnz# cat /proc/rd/status
618 OK
620 The above messages indicate that everything is healthy, and /proc/rd/status
621 returns "OK" indicating that there are no problems with any DAC960 controller
622 in the system. For demonstration purposes, while I/O is active Physical Drive
623 1:2 is now disconnected, simulating a drive failure. The failure is noted by
624 the driver within 10 seconds of the controller's having detected it, and the
625 driver logs the following console status messages:
627 DAC960#0: Physical Drive 1:1 Error Log: Sense Key = 6, ASC = 29, ASCQ = 02
628 DAC960#0: Physical Drive 1:3 Error Log: Sense Key = 6, ASC = 29, ASCQ = 02
629 DAC960#0: Physical Drive 1:2 killed because of timeout on SCSI command
630 DAC960#0: Physical Drive 1:2 is now DEAD
631 DAC960#0: Physical Drive 1:2 killed because it was removed
632 DAC960#0: Logical Drive 0 (/dev/rd/c0d0) is now CRITICAL
633 DAC960#0: Logical Drive 1 (/dev/rd/c0d1) is now CRITICAL
635 Since a standby drive is configured, the controller automatically begins
636 rebuilding onto the standby drive:
638 DAC960#0: Physical Drive 1:3 is now WRITE-ONLY
639 DAC960#0: Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 4% completed
641 Concurrently with the above, the driver status available from /proc/rd also
642 reflects the drive failure and automatic rebuild. The status message in
643 /proc/rd/status has changed from "OK" to "ALERT":
645 gwynedd:/u/lnz# cat /proc/rd/status
646 ALERT
648 and /proc/rd/c0/current_status has been updated:
650 gwynedd:/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
664 As the rebuild progresses, the current status in /proc/rd/c0/current_status is
665 updated every 10 seconds:
667 gwynedd:/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
681 and every minute a progress message is logged on the console by the driver:
683 DAC960#0: Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 40% completed
684 DAC960#0: Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 76% completed
685 DAC960#0: Rebuild in Progress: Logical Drive 1 (/dev/rd/c0d1) 66% completed
686 DAC960#0: Rebuild in Progress: Logical Drive 1 (/dev/rd/c0d1) 84% completed
688 Finally, the rebuild completes successfully. The driver logs the status of the
689 logical and physical drives and the rebuild completion:
691 DAC960#0: Rebuild Completed Successfully
692 DAC960#0: Physical Drive 1:3 is now ONLINE
693 DAC960#0: Logical Drive 0 (/dev/rd/c0d0) is now ONLINE
694 DAC960#0: Logical Drive 1 (/dev/rd/c0d1) is now ONLINE
696 /proc/rd/c0/current_status is updated:
698 ***** DAC960 RAID Driver Version 2.0.0 of 23 March 1999 *****
699 Copyright 1998-1999 by Leonard N. Zubkoff <lnz@dandelion.com>
700 Configuring 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
719 and /proc/rd/status indicates that everything is healthy once again:
721 gwynedd:/u/lnz# cat /proc/rd/status
722 OK
724 Note that the absence of a viable standby drive does not create an "ALERT"
725 status. Once dead Physical Drive 1:2 has been replaced, the controller must be
726 told that this has occurred and that the newly replaced drive should become the
727 new standby drive:
729 gwynedd:/u/lnz# echo "make-standby 1:2" > /proc/rd/c0/user_command
730 gwynedd:/u/lnz# cat /proc/rd/c0/user_command
731 Make Standby of Physical Drive 1:2 Succeeded
733 The echo command instructs the controller to make Physical Drive 1:2 into a
734 standby drive, and the status message that results from the operation is then
735 available for reading from /proc/rd/c0/user_command, as well as being logged to
736 the console by the driver. Within 60 seconds of this command the driver logs:
738 DAC960#0: Physical Drive 1:2 Error Log: Sense Key = 6, ASC = 29, ASCQ = 01
739 DAC960#0: Physical Drive 1:2 is now STANDBY
740 DAC960#0: Make Standby of Physical Drive 1:2 Succeeded
742 and /proc/rd/c0/current_status is updated:
744 gwynedd:/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