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 * SA P700m 25 * SA P212 26 * SA P410 27 * SA P410i 28 * SA P411 29 * SA P812 30 * SA P712m 31 * SA P711m 32 33Detecting drive failures: 34------------------------- 35 36To get the status of logical volumes and to detect physical drive 37failures, you can use the cciss_vol_status program found here: 38http://cciss.sourceforge.net/#cciss_utils 39 40Device Naming: 41-------------- 42 43If nodes are not already created in the /dev/cciss directory, run as root: 44 45# cd /dev 46# ./MAKEDEV cciss 47 48You need some entries in /dev for the cciss device. The MAKEDEV script 49can make device nodes for you automatically. Currently the device setup 50is as follows: 51 52Major 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 62Minor 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 70The 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 81SCSI tape drive and medium changer support 82------------------------------------------ 83 84SCSI sequential access devices and medium changer devices are supported and 85appropriate device nodes are automatically created. (e.g. 86/dev/st0, /dev/st1, etc. See the "st" man page for more details.) 87You must enable "SCSI tape drive support for Smart Array 5xxx" and 88"SCSI support" in your kernel configuration to be able to use SCSI 89tape drives with your Smart Array 5xxx controller. 90 91Additionally, note that the driver will not engage the SCSI core at init 92time. The driver must be directed to dynamically engage the SCSI core via 93the /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, 95the SCSI core may not yet be initialized (because the driver is a block 96driver) and attempting to register it with the SCSI core in such a case 97would cause a hang. This is best done via an initialization script 98(typically in /etc/init.d, but could vary depending on distribution). 99For example: 100 101 for x in /proc/driver/cciss/cciss[0-9]* 102 do 103 echo "engage scsi" > $x 104 done 105 106Once 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 109Note also that if no sequential access devices or medium changers are 110detected, the SCSI core will not be engaged by the action of the above 111script. 112 113Hot plug support for SCSI tape drives 114------------------------------------- 115 116Hot plugging of SCSI tape drives is supported, with some caveats. 117The cciss driver must be informed that changes to the SCSI bus 118have been made. This may be done via the /proc filesystem. 119For example: 120 121 echo "rescan" > /proc/scsi/cciss0/1 122 123This causes the driver to query the adapter about changes to the 124physical SCSI buses and/or fibre channel arbitrated loop and the 125driver to make note of any new or removed sequential access devices 126or medium changers. The driver will output messages indicating what 127devices have been added or removed and the controller, bus, target and 128lun used to address the device. It then notifies the SCSI mid layer 129of these changes. 130 131Note that the naming convention of the /proc filesystem entries 132contains a number in addition to the driver name. (E.g. "cciss0" 133instead of just "cciss" which you might expect.) 134 135Note: ONLY sequential access devices and medium changers are presented 136as SCSI devices to the SCSI mid layer by the cciss driver. Specifically, 137physical SCSI disk drives are NOT presented to the SCSI mid layer. The 138physical SCSI disk drives are controlled directly by the array controller 139hardware and it is important to prevent the kernel from attempting to directly 140access these devices too, as if the array controller were merely a SCSI 141controller in the same way that we are allowing it to access SCSI tape drives. 142 143SCSI error handling for tape drives and medium changers 144------------------------------------------------------- 145 146The linux SCSI mid layer provides an error handling protocol which 147kicks into gear whenever a SCSI command fails to complete within a 148certain amount of time (which can vary depending on the command). 149The cciss driver participates in this protocol to some extent. The 150normal protocol is a four step process. First the device is told 151to abort the command. If that doesn't work, the device is reset. 152If that doesn't work, the SCSI bus is reset. If that doesn't work 153the host bus adapter is reset. Because the cciss driver is a block 154driver as well as a SCSI driver and only the tape drives and medium 155changers are presented to the SCSI mid layer, and unlike more 156straightforward SCSI drivers, disk i/o continues through the block 157side during the SCSI error recovery process, the cciss driver only 158implements the first two of these actions, aborting the command, and 159resetting the device. Additionally, most tape drives will not oblige 160in aborting commands, and sometimes it appears they will not even 161obey a reset command, though in most circumstances they will. In 162the case that the command cannot be aborted and the device cannot be 163reset, the device will be set offline. 164 165In the event the error handling code is triggered and a tape drive is 166successfully reset or the tardy command is successfully aborted, the 167tape drive may still not allow i/o to continue until some command 168is issued which positions the tape to a known position. Typically you 169must rewind the tape (by issuing "mt -f /dev/st0 rewind" for example) 170before i/o can proceed again to a tape drive which was reset. 171 172