Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 |
Mike Miller | 9dc7a86 | 2005-09-13 01:25:19 -0700 | [diff] [blame] | 20 | * SA P400i |
| 21 | * SA E200 |
| 22 | * SA E200i |
Mike Miller | 1883c5a | 2006-09-12 20:36:07 -0700 | [diff] [blame] | 23 | * SA E500 |
dann frazier | fd96feb | 2008-11-06 12:53:34 -0800 | [diff] [blame] | 24 | * SA P700m |
Mike Miller | 24aac48 | 2008-06-12 15:21:34 -0700 | [diff] [blame] | 25 | * SA P212 |
| 26 | * SA P410 |
| 27 | * SA P410i |
| 28 | * SA P411 |
| 29 | * SA P812 |
Mike Miller | 77ca728 | 2008-11-06 12:53:14 -0800 | [diff] [blame] | 30 | * SA P712m |
| 31 | * SA P711m |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 32 | |
Stephen M. Cameron | 6c080f1 | 2007-05-08 00:30:05 -0700 | [diff] [blame] | 33 | Detecting drive failures: |
| 34 | ------------------------- |
| 35 | |
| 36 | To get the status of logical volumes and to detect physical drive |
| 37 | failures, you can use the cciss_vol_status program found here: |
| 38 | http://cciss.sourceforge.net/#cciss_utils |
| 39 | |
| 40 | Device Naming: |
| 41 | -------------- |
| 42 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 43 | If nodes are not already created in the /dev/cciss directory, run as root: |
| 44 | |
| 45 | # cd /dev |
| 46 | # ./MAKEDEV cciss |
| 47 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 48 | You need some entries in /dev for the cciss device. The MAKEDEV script |
| 49 | can make device nodes for you automatically. Currently the device setup |
| 50 | is as follows: |
| 51 | |
| 52 | Major numbers: |
| 53 | 104 cciss0 |
| 54 | 105 cciss1 |
| 55 | 106 cciss2 |
| 56 | 105 cciss3 |
| 57 | 108 cciss4 |
| 58 | 109 cciss5 |
| 59 | 110 cciss6 |
| 60 | 111 cciss7 |
| 61 | |
| 62 | Minor numbers: |
| 63 | b7 b6 b5 b4 b3 b2 b1 b0 |
| 64 | |----+----| |----+----| |
| 65 | | | |
| 66 | | +-------- Partition ID (0=wholedev, 1-15 partition) |
| 67 | | |
| 68 | +-------------------- Logical Volume number |
| 69 | |
| 70 | The device naming scheme is: |
| 71 | /dev/cciss/c0d0 Controller 0, disk 0, whole device |
| 72 | /dev/cciss/c0d0p1 Controller 0, disk 0, partition 1 |
| 73 | /dev/cciss/c0d0p2 Controller 0, disk 0, partition 2 |
| 74 | /dev/cciss/c0d0p3 Controller 0, disk 0, partition 3 |
| 75 | |
| 76 | /dev/cciss/c1d1 Controller 1, disk 1, whole device |
| 77 | /dev/cciss/c1d1p1 Controller 1, disk 1, partition 1 |
| 78 | /dev/cciss/c1d1p2 Controller 1, disk 1, partition 2 |
| 79 | /dev/cciss/c1d1p3 Controller 1, disk 1, partition 3 |
| 80 | |
| 81 | SCSI tape drive and medium changer support |
| 82 | ------------------------------------------ |
| 83 | |
| 84 | SCSI sequential access devices and medium changer devices are supported and |
| 85 | appropriate device nodes are automatically created. (e.g. |
| 86 | /dev/st0, /dev/st1, etc. See the "st" man page for more details.) |
| 87 | You must enable "SCSI tape drive support for Smart Array 5xxx" and |
| 88 | "SCSI support" in your kernel configuration to be able to use SCSI |
| 89 | tape drives with your Smart Array 5xxx controller. |
| 90 | |
| 91 | Additionally, note that the driver will not engage the SCSI core at init |
| 92 | time. The driver must be directed to dynamically engage the SCSI core via |
| 93 | the /proc filesystem entry which the "block" side of the driver creates as |
| 94 | /proc/driver/cciss/cciss* at runtime. This is because at driver init time, |
| 95 | the SCSI core may not yet be initialized (because the driver is a block |
| 96 | driver) and attempting to register it with the SCSI core in such a case |
| 97 | would cause a hang. This is best done via an initialization script |
Matt LaPlante | fff9289 | 2006-10-03 22:47:42 +0200 | [diff] [blame] | 98 | (typically in /etc/init.d, but could vary depending on distribution). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 99 | For example: |
| 100 | |
| 101 | for x in /proc/driver/cciss/cciss[0-9]* |
| 102 | do |
| 103 | echo "engage scsi" > $x |
| 104 | done |
| 105 | |
| 106 | Once the SCSI core is engaged by the driver, it cannot be disengaged |
| 107 | (except by unloading the driver, if it happens to be linked as a module.) |
| 108 | |
| 109 | Note also that if no sequential access devices or medium changers are |
| 110 | detected, the SCSI core will not be engaged by the action of the above |
| 111 | script. |
| 112 | |
| 113 | Hot plug support for SCSI tape drives |
| 114 | ------------------------------------- |
| 115 | |
| 116 | Hot plugging of SCSI tape drives is supported, with some caveats. |
| 117 | The cciss driver must be informed that changes to the SCSI bus |
Mike Miller | f4a93bc | 2008-08-04 11:54:53 +0200 | [diff] [blame] | 118 | have been made. This may be done via the /proc filesystem. |
| 119 | For example: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 120 | |
| 121 | echo "rescan" > /proc/scsi/cciss0/1 |
| 122 | |
Mike Miller | f4a93bc | 2008-08-04 11:54:53 +0200 | [diff] [blame] | 123 | This causes the driver to query the adapter about changes to the |
| 124 | physical SCSI buses and/or fibre channel arbitrated loop and the |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 125 | driver to make note of any new or removed sequential access devices |
| 126 | or medium changers. The driver will output messages indicating what |
| 127 | devices have been added or removed and the controller, bus, target and |
Mike Miller | f4a93bc | 2008-08-04 11:54:53 +0200 | [diff] [blame] | 128 | lun used to address the device. It then notifies the SCSI mid layer |
| 129 | of these changes. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 130 | |
| 131 | Note that the naming convention of the /proc filesystem entries |
| 132 | contains a number in addition to the driver name. (E.g. "cciss0" |
| 133 | instead of just "cciss" which you might expect.) |
| 134 | |
| 135 | Note: ONLY sequential access devices and medium changers are presented |
| 136 | as SCSI devices to the SCSI mid layer by the cciss driver. Specifically, |
| 137 | physical SCSI disk drives are NOT presented to the SCSI mid layer. The |
| 138 | physical SCSI disk drives are controlled directly by the array controller |
| 139 | hardware and it is important to prevent the kernel from attempting to directly |
| 140 | access these devices too, as if the array controller were merely a SCSI |
| 141 | controller in the same way that we are allowing it to access SCSI tape drives. |
| 142 | |
mike.miller@hp.com | 3da8b71 | 2005-11-04 12:30:37 -0600 | [diff] [blame] | 143 | SCSI error handling for tape drives and medium changers |
| 144 | ------------------------------------------------------- |
| 145 | |
| 146 | The linux SCSI mid layer provides an error handling protocol which |
| 147 | kicks into gear whenever a SCSI command fails to complete within a |
| 148 | certain amount of time (which can vary depending on the command). |
| 149 | The cciss driver participates in this protocol to some extent. The |
| 150 | normal protocol is a four step process. First the device is told |
| 151 | to abort the command. If that doesn't work, the device is reset. |
| 152 | If that doesn't work, the SCSI bus is reset. If that doesn't work |
| 153 | the host bus adapter is reset. Because the cciss driver is a block |
| 154 | driver as well as a SCSI driver and only the tape drives and medium |
| 155 | changers are presented to the SCSI mid layer, and unlike more |
| 156 | straightforward SCSI drivers, disk i/o continues through the block |
| 157 | side during the SCSI error recovery process, the cciss driver only |
| 158 | implements the first two of these actions, aborting the command, and |
| 159 | resetting the device. Additionally, most tape drives will not oblige |
| 160 | in aborting commands, and sometimes it appears they will not even |
Matt LaPlante | 6c28f2c | 2006-10-03 22:46:31 +0200 | [diff] [blame] | 161 | obey a reset command, though in most circumstances they will. In |
mike.miller@hp.com | 3da8b71 | 2005-11-04 12:30:37 -0600 | [diff] [blame] | 162 | the case that the command cannot be aborted and the device cannot be |
| 163 | reset, the device will be set offline. |
| 164 | |
| 165 | In the event the error handling code is triggered and a tape drive is |
| 166 | successfully reset or the tardy command is successfully aborted, the |
| 167 | tape drive may still not allow i/o to continue until some command |
| 168 | is issued which positions the tape to a known position. Typically you |
| 169 | must rewind the tape (by issuing "mt -f /dev/st0 rewind" for example) |
| 170 | before i/o can proceed again to a tape drive which was reset. |
| 171 | |
Stephen M. Cameron | 8a4ec67 | 2011-05-03 14:54:12 -0500 | [diff] [blame^] | 172 | There is a cciss_tape_cmds module parameter which can be used to make cciss |
| 173 | allocate more commands for use by tape drives. Ordinarily only a few commands |
| 174 | (6) are allocated for tape drives because tape drives are slow and |
| 175 | infrequently used and the primary purpose of Smart Array controllers is to |
| 176 | act as a RAID controller for disk drives, so the vast majority of commands |
| 177 | are allocated for disk devices. However, if you have more than a few tape |
| 178 | drives attached to a smart array, the default number of commands may not be |
| 179 | enought (for example, if you have 8 tape drives, you could only rewind 6 |
| 180 | at one time with the default number of commands.) The cciss_tape_cmds module |
| 181 | parameter allows more commands (up to 16 more) to be allocated for use by |
| 182 | tape drives. For example: |
| 183 | |
| 184 | insmod cciss.ko cciss_tape_cmds=16 |
| 185 | |
| 186 | Or, as a kernel boot parameter passed in via grub: cciss.cciss_tape_cmds=8 |