Documentation/cciss.txt

   1 This driver is for Compaq's SMART Array Controllers.
   2
   3 Supported Cards:
   4 ----------------
   5
   6 This 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
  20
  21 If nodes are not already created in the /dev/cciss directory, run as root:
  22
  23 # cd /dev
  24 # ./MAKEDEV cciss
  25
  26 Device Naming:
  27 --------------
  28
  29 You need some entries in /dev for the cciss device.  The MAKEDEV script
  30 can make device nodes for you automatically.  Currently the device setup
  31 is as follows:
  32
  33 Major numbers:
  34         104     cciss0
  35         105     cciss1
  36         106     cciss2
  37         105     cciss3
  38         108     cciss4
  39         109     cciss5
  40         110     cciss6
  41         111     cciss7
  42
  43 Minor numbers:
  44         b7 b6 b5 b4 b3 b2 b1 b0
  45         |----+----| |----+----|
  46              |           |
  47              |           +-------- Partition ID (0=wholedev, 1-15 partition)
  48              |
  49              +-------------------- Logical Volume number
  50
  51 The device naming scheme is:
  52 /dev/cciss/c0d0                 Controller 0, disk 0, whole device
  53 /dev/cciss/c0d0p1               Controller 0, disk 0, partition 1
  54 /dev/cciss/c0d0p2               Controller 0, disk 0, partition 2
  55 /dev/cciss/c0d0p3               Controller 0, disk 0, partition 3
  56
  57 /dev/cciss/c1d1                 Controller 1, disk 1, whole device
  58 /dev/cciss/c1d1p1               Controller 1, disk 1, partition 1
  59 /dev/cciss/c1d1p2               Controller 1, disk 1, partition 2
  60 /dev/cciss/c1d1p3               Controller 1, disk 1, partition 3
  61
  62 SCSI tape drive and medium changer support
  63 ------------------------------------------
  64
  65 SCSI sequential access devices and medium changer devices are supported and
  66 appropriate device nodes are automatically created.  (e.g.
  67 /dev/st0, /dev/st1, etc.  See the "st" man page for more details.)
  68 You must enable "SCSI tape drive support for Smart Array 5xxx" and
  69 "SCSI support" in your kernel configuration to be able to use SCSI
  70 tape drives with your Smart Array 5xxx controller.
  71
  72 Additionally, note that the driver will not engage the SCSI core at init
  73 time.  The driver must be directed to dynamically engage the SCSI core via
  74 the /proc filesystem entry which the "block" side of the driver creates as
  75 /proc/driver/cciss/cciss* at runtime.  This is because at driver init time,
  76 the SCSI core may not yet be initialized (because the driver is a block
  77 driver) and attempting to register it with the SCSI core in such a case
  78 would cause a hang.  This is best done via an initialization script
  79 (typically in /etc/init.d, but could vary depending on distibution).
  80 For example:
  81
  82         for x in /proc/driver/cciss/cciss[0-9]*
  83         do
  84                 echo "engage scsi" > $x
  85         done
  86
  87 Once the SCSI core is engaged by the driver, it cannot be disengaged
  88 (except by unloading the driver, if it happens to be linked as a module.)
  89
  90 Note also that if no sequential access devices or medium changers are
  91 detected, the SCSI core will not be engaged by the action of the above
  92 script.
  93
  94 Hot plug support for SCSI tape drives
  95 -------------------------------------
  96
  97 Hot plugging of SCSI tape drives is supported, with some caveats.
  98 The cciss driver must be informed that changes to the SCSI bus
  99 have been made, in addition to and prior to informing the SCSI
 100 mid layer.  This may be done via the /proc filesystem.  For example:
 101
 102         echo "rescan" > /proc/scsi/cciss0/1
 103
 104 This causes the adapter to query the adapter about changes to the
 105 physical SCSI buses and/or fibre channel arbitrated loop and the
 106 driver to make note of any new or removed sequential access devices
 107 or medium changers.  The driver will output messages indicating what
 108 devices have been added or removed and the controller, bus, target and
 109 lun used to address the device.  Once this is done, the SCSI mid layer
 110 can be informed of changes to the virtual SCSI bus which the driver
 111 presents to it in the usual way. For example:
 112
 113         echo scsi add-single-device 3 2 1 0 > /proc/scsi/scsi
 114
 115 to add a device on controller 3, bus 2, target 1, lun 0.   Note that
 116 the driver makes an effort to preserve the devices positions
 117 in the virtual SCSI bus, so if you are only moving tape drives
 118 around on the same adapter and not adding or removing tape drives
 119 from the adapter, informing the SCSI mid layer may not be necessary.
 120
 121 Note that the naming convention of the /proc filesystem entries
 122 contains a number in addition to the driver name.  (E.g. "cciss0"
 123 instead of just "cciss" which you might expect.)
 124
 125 Note: ONLY sequential access devices and medium changers are presented
 126 as SCSI devices to the SCSI mid layer by the cciss driver.  Specifically,
 127 physical SCSI disk drives are NOT presented to the SCSI mid layer.  The
 128 physical SCSI disk drives are controlled directly by the array controller
 129 hardware and it is important to prevent the kernel from attempting to directly
 130 access these devices too, as if the array controller were merely a SCSI
 131 controller in the same way that we are allowing it to access SCSI tape drives.
 132