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