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Linus Torvalds1da177e2005-04-16 15:20:36 -07001This driver is for Compaq's SMART Array Controllers.
2
3Supported Cards:
4----------------
5
6This driver is known to work with the following cards:
7
8 * SA 5300
9 * SA 5i
10 * SA 532
11 * SA 5312
12 * SA 641
13 * SA 642
14 * SA 6400
15 * SA 6400 U320 Expansion Module
16 * SA 6i
17 * SA P600
18 * SA P800
19 * SA E400
Mike Miller9dc7a862005-09-13 01:25:19 -070020 * SA P400i
21 * SA E200
22 * SA E200i
Mike Miller1883c5a2006-09-12 20:36:07 -070023 * SA E500
Mike Miller24aac482008-06-12 15:21:34 -070024 * SA P212
25 * SA P410
26 * SA P410i
27 * SA P411
28 * SA P812
Linus Torvalds1da177e2005-04-16 15:20:36 -070029
Stephen M. Cameron6c080f12007-05-08 00:30:05 -070030Detecting drive failures:
31-------------------------
32
33To get the status of logical volumes and to detect physical drive
34failures, you can use the cciss_vol_status program found here:
35http://cciss.sourceforge.net/#cciss_utils
36
37Device Naming:
38--------------
39
Linus Torvalds1da177e2005-04-16 15:20:36 -070040If nodes are not already created in the /dev/cciss directory, run as root:
41
42# cd /dev
43# ./MAKEDEV cciss
44
Linus Torvalds1da177e2005-04-16 15:20:36 -070045You need some entries in /dev for the cciss device. The MAKEDEV script
46can make device nodes for you automatically. Currently the device setup
47is as follows:
48
49Major numbers:
50 104 cciss0
51 105 cciss1
52 106 cciss2
53 105 cciss3
54 108 cciss4
55 109 cciss5
56 110 cciss6
57 111 cciss7
58
59Minor numbers:
60 b7 b6 b5 b4 b3 b2 b1 b0
61 |----+----| |----+----|
62 | |
63 | +-------- Partition ID (0=wholedev, 1-15 partition)
64 |
65 +-------------------- Logical Volume number
66
67The device naming scheme is:
68/dev/cciss/c0d0 Controller 0, disk 0, whole device
69/dev/cciss/c0d0p1 Controller 0, disk 0, partition 1
70/dev/cciss/c0d0p2 Controller 0, disk 0, partition 2
71/dev/cciss/c0d0p3 Controller 0, disk 0, partition 3
72
73/dev/cciss/c1d1 Controller 1, disk 1, whole device
74/dev/cciss/c1d1p1 Controller 1, disk 1, partition 1
75/dev/cciss/c1d1p2 Controller 1, disk 1, partition 2
76/dev/cciss/c1d1p3 Controller 1, disk 1, partition 3
77
78SCSI tape drive and medium changer support
79------------------------------------------
80
81SCSI sequential access devices and medium changer devices are supported and
82appropriate device nodes are automatically created. (e.g.
83/dev/st0, /dev/st1, etc. See the "st" man page for more details.)
84You must enable "SCSI tape drive support for Smart Array 5xxx" and
85"SCSI support" in your kernel configuration to be able to use SCSI
86tape drives with your Smart Array 5xxx controller.
87
88Additionally, note that the driver will not engage the SCSI core at init
89time. The driver must be directed to dynamically engage the SCSI core via
90the /proc filesystem entry which the "block" side of the driver creates as
91/proc/driver/cciss/cciss* at runtime. This is because at driver init time,
92the SCSI core may not yet be initialized (because the driver is a block
93driver) and attempting to register it with the SCSI core in such a case
94would cause a hang. This is best done via an initialization script
Matt LaPlantefff92892006-10-03 22:47:42 +020095(typically in /etc/init.d, but could vary depending on distribution).
Linus Torvalds1da177e2005-04-16 15:20:36 -070096For example:
97
98 for x in /proc/driver/cciss/cciss[0-9]*
99 do
100 echo "engage scsi" > $x
101 done
102
103Once the SCSI core is engaged by the driver, it cannot be disengaged
104(except by unloading the driver, if it happens to be linked as a module.)
105
106Note also that if no sequential access devices or medium changers are
107detected, the SCSI core will not be engaged by the action of the above
108script.
109
110Hot plug support for SCSI tape drives
111-------------------------------------
112
113Hot plugging of SCSI tape drives is supported, with some caveats.
114The cciss driver must be informed that changes to the SCSI bus
115have been made, in addition to and prior to informing the SCSI
116mid layer. This may be done via the /proc filesystem. For example:
117
118 echo "rescan" > /proc/scsi/cciss0/1
119
120This causes the adapter to query the adapter about changes to the
121physical SCSI buses and/or fibre channel arbitrated loop and the
122driver to make note of any new or removed sequential access devices
123or medium changers. The driver will output messages indicating what
124devices have been added or removed and the controller, bus, target and
125lun used to address the device. Once this is done, the SCSI mid layer
126can be informed of changes to the virtual SCSI bus which the driver
127presents to it in the usual way. For example:
128
129 echo scsi add-single-device 3 2 1 0 > /proc/scsi/scsi
130
131to add a device on controller 3, bus 2, target 1, lun 0. Note that
132the driver makes an effort to preserve the devices positions
133in the virtual SCSI bus, so if you are only moving tape drives
134around on the same adapter and not adding or removing tape drives
135from the adapter, informing the SCSI mid layer may not be necessary.
136
137Note that the naming convention of the /proc filesystem entries
138contains a number in addition to the driver name. (E.g. "cciss0"
139instead of just "cciss" which you might expect.)
140
141Note: ONLY sequential access devices and medium changers are presented
142as SCSI devices to the SCSI mid layer by the cciss driver. Specifically,
143physical SCSI disk drives are NOT presented to the SCSI mid layer. The
144physical SCSI disk drives are controlled directly by the array controller
145hardware and it is important to prevent the kernel from attempting to directly
146access these devices too, as if the array controller were merely a SCSI
147controller in the same way that we are allowing it to access SCSI tape drives.
148
mike.miller@hp.com3da8b712005-11-04 12:30:37 -0600149SCSI error handling for tape drives and medium changers
150-------------------------------------------------------
151
152The linux SCSI mid layer provides an error handling protocol which
153kicks into gear whenever a SCSI command fails to complete within a
154certain amount of time (which can vary depending on the command).
155The cciss driver participates in this protocol to some extent. The
156normal protocol is a four step process. First the device is told
157to abort the command. If that doesn't work, the device is reset.
158If that doesn't work, the SCSI bus is reset. If that doesn't work
159the host bus adapter is reset. Because the cciss driver is a block
160driver as well as a SCSI driver and only the tape drives and medium
161changers are presented to the SCSI mid layer, and unlike more
162straightforward SCSI drivers, disk i/o continues through the block
163side during the SCSI error recovery process, the cciss driver only
164implements the first two of these actions, aborting the command, and
165resetting the device. Additionally, most tape drives will not oblige
166in aborting commands, and sometimes it appears they will not even
Matt LaPlante6c28f2c2006-10-03 22:46:31 +0200167obey a reset command, though in most circumstances they will. In
mike.miller@hp.com3da8b712005-11-04 12:30:37 -0600168the case that the command cannot be aborted and the device cannot be
169reset, the device will be set offline.
170
171In the event the error handling code is triggered and a tape drive is
172successfully reset or the tardy command is successfully aborted, the
173tape drive may still not allow i/o to continue until some command
174is issued which positions the tape to a known position. Typically you
175must rewind the tape (by issuing "mt -f /dev/st0 rewind" for example)
176before i/o can proceed again to a tape drive which was reset.
177