1# 2# Block device driver configuration 3# 4 5if BLOCK 6 7menu "Multi-device support (RAID and LVM)" 8 9config MD 10 bool "Multiple devices driver support (RAID and LVM)" 11 help 12 Support multiple physical spindles through a single logical device. 13 Required for RAID and logical volume management. 14 15config BLK_DEV_MD 16 tristate "RAID support" 17 depends on MD 18 ---help--- 19 This driver lets you combine several hard disk partitions into one 20 logical block device. This can be used to simply append one 21 partition to another one or to combine several redundant hard disks 22 into a RAID1/4/5 device so as to provide protection against hard 23 disk failures. This is called "Software RAID" since the combining of 24 the partitions is done by the kernel. "Hardware RAID" means that the 25 combining is done by a dedicated controller; if you have such a 26 controller, you do not need to say Y here. 27 28 More information about Software RAID on Linux is contained in the 29 Software RAID mini-HOWTO, available from 30 <http://www.tldp.org/docs.html#howto>. There you will also learn 31 where to get the supporting user space utilities raidtools. 32 33 If unsure, say N. 34 35config MD_LINEAR 36 tristate "Linear (append) mode" 37 depends on BLK_DEV_MD 38 ---help--- 39 If you say Y here, then your multiple devices driver will be able to 40 use the so-called linear mode, i.e. it will combine the hard disk 41 partitions by simply appending one to the other. 42 43 To compile this as a module, choose M here: the module 44 will be called linear. 45 46 If unsure, say Y. 47 48config MD_RAID0 49 tristate "RAID-0 (striping) mode" 50 depends on BLK_DEV_MD 51 ---help--- 52 If you say Y here, then your multiple devices driver will be able to 53 use the so-called raid0 mode, i.e. it will combine the hard disk 54 partitions into one logical device in such a fashion as to fill them 55 up evenly, one chunk here and one chunk there. This will increase 56 the throughput rate if the partitions reside on distinct disks. 57 58 Information about Software RAID on Linux is contained in the 59 Software-RAID mini-HOWTO, available from 60 <http://www.tldp.org/docs.html#howto>. There you will also 61 learn where to get the supporting user space utilities raidtools. 62 63 To compile this as a module, choose M here: the module 64 will be called raid0. 65 66 If unsure, say Y. 67 68config MD_RAID1 69 tristate "RAID-1 (mirroring) mode" 70 depends on BLK_DEV_MD 71 ---help--- 72 A RAID-1 set consists of several disk drives which are exact copies 73 of each other. In the event of a mirror failure, the RAID driver 74 will continue to use the operational mirrors in the set, providing 75 an error free MD (multiple device) to the higher levels of the 76 kernel. In a set with N drives, the available space is the capacity 77 of a single drive, and the set protects against a failure of (N - 1) 78 drives. 79 80 Information about Software RAID on Linux is contained in the 81 Software-RAID mini-HOWTO, available from 82 <http://www.tldp.org/docs.html#howto>. There you will also 83 learn where to get the supporting user space utilities raidtools. 84 85 If you want to use such a RAID-1 set, say Y. To compile this code 86 as a module, choose M here: the module will be called raid1. 87 88 If unsure, say Y. 89 90config MD_RAID10 91 tristate "RAID-10 (mirrored striping) mode (EXPERIMENTAL)" 92 depends on BLK_DEV_MD && EXPERIMENTAL 93 ---help--- 94 RAID-10 provides a combination of striping (RAID-0) and 95 mirroring (RAID-1) with easier configuration and more flexible 96 layout. 97 Unlike RAID-0, but like RAID-1, RAID-10 requires all devices to 98 be the same size (or at least, only as much as the smallest device 99 will be used). 100 RAID-10 provides a variety of layouts that provide different levels 101 of redundancy and performance. 102 103 RAID-10 requires mdadm-1.7.0 or later, available at: 104 105 ftp://ftp.kernel.org/pub/linux/utils/raid/mdadm/ 106 107 If unsure, say Y. 108 109config MD_RAID456 110 tristate "RAID-4/RAID-5/RAID-6 mode" 111 depends on BLK_DEV_MD 112 ---help--- 113 A RAID-5 set of N drives with a capacity of C MB per drive provides 114 the capacity of C * (N - 1) MB, and protects against a failure 115 of a single drive. For a given sector (row) number, (N - 1) drives 116 contain data sectors, and one drive contains the parity protection. 117 For a RAID-4 set, the parity blocks are present on a single drive, 118 while a RAID-5 set distributes the parity across the drives in one 119 of the available parity distribution methods. 120 121 A RAID-6 set of N drives with a capacity of C MB per drive 122 provides the capacity of C * (N - 2) MB, and protects 123 against a failure of any two drives. For a given sector 124 (row) number, (N - 2) drives contain data sectors, and two 125 drives contains two independent redundancy syndromes. Like 126 RAID-5, RAID-6 distributes the syndromes across the drives 127 in one of the available parity distribution methods. 128 129 Information about Software RAID on Linux is contained in the 130 Software-RAID mini-HOWTO, available from 131 <http://www.tldp.org/docs.html#howto>. There you will also 132 learn where to get the supporting user space utilities raidtools. 133 134 If you want to use such a RAID-4/RAID-5/RAID-6 set, say Y. To 135 compile this code as a module, choose M here: the module 136 will be called raid456. 137 138 If unsure, say Y. 139 140config MD_RAID5_RESHAPE 141 bool "Support adding drives to a raid-5 array" 142 depends on MD_RAID456 143 default y 144 ---help--- 145 A RAID-5 set can be expanded by adding extra drives. This 146 requires "restriping" the array which means (almost) every 147 block must be written to a different place. 148 149 This option allows such restriping to be done while the array 150 is online. 151 152 You will need mdadm version 2.4.1 or later to use this 153 feature safely. During the early stage of reshape there is 154 a critical section where live data is being over-written. A 155 crash during this time needs extra care for recovery. The 156 newer mdadm takes a copy of the data in the critical section 157 and will restore it, if necessary, after a crash. 158 159 The mdadm usage is e.g. 160 mdadm --grow /dev/md1 --raid-disks=6 161 to grow '/dev/md1' to having 6 disks. 162 163 Note: The array can only be expanded, not contracted. 164 There should be enough spares already present to make the new 165 array workable. 166 167 If unsure, say Y. 168 169config MD_MULTIPATH 170 tristate "Multipath I/O support" 171 depends on BLK_DEV_MD 172 help 173 Multipath-IO is the ability of certain devices to address the same 174 physical disk over multiple 'IO paths'. The code ensures that such 175 paths can be defined and handled at runtime, and ensures that a 176 transparent failover to the backup path(s) happens if a IO errors 177 arrives on the primary path. 178 179 If unsure, say N. 180 181config MD_FAULTY 182 tristate "Faulty test module for MD" 183 depends on BLK_DEV_MD 184 help 185 The "faulty" module allows for a block device that occasionally returns 186 read or write errors. It is useful for testing. 187 188 In unsure, say N. 189 190config BLK_DEV_DM 191 tristate "Device mapper support" 192 depends on MD 193 ---help--- 194 Device-mapper is a low level volume manager. It works by allowing 195 people to specify mappings for ranges of logical sectors. Various 196 mapping types are available, in addition people may write their own 197 modules containing custom mappings if they wish. 198 199 Higher level volume managers such as LVM2 use this driver. 200 201 To compile this as a module, choose M here: the module will be 202 called dm-mod. 203 204 If unsure, say N. 205 206config DM_DEBUG 207 boolean "Device mapper debugging support" 208 depends on BLK_DEV_DM && EXPERIMENTAL 209 ---help--- 210 Enable this for messages that may help debug device-mapper problems. 211 212 If unsure, say N. 213 214config DM_CRYPT 215 tristate "Crypt target support" 216 depends on BLK_DEV_DM && EXPERIMENTAL 217 select CRYPTO 218 select CRYPTO_CBC 219 ---help--- 220 This device-mapper target allows you to create a device that 221 transparently encrypts the data on it. You'll need to activate 222 the ciphers you're going to use in the cryptoapi configuration. 223 224 Information on how to use dm-crypt can be found on 225 226 <http://www.saout.de/misc/dm-crypt/> 227 228 To compile this code as a module, choose M here: the module will 229 be called dm-crypt. 230 231 If unsure, say N. 232 233config DM_SNAPSHOT 234 tristate "Snapshot target (EXPERIMENTAL)" 235 depends on BLK_DEV_DM && EXPERIMENTAL 236 ---help--- 237 Allow volume managers to take writable snapshots of a device. 238 239config DM_MIRROR 240 tristate "Mirror target (EXPERIMENTAL)" 241 depends on BLK_DEV_DM && EXPERIMENTAL 242 ---help--- 243 Allow volume managers to mirror logical volumes, also 244 needed for live data migration tools such as 'pvmove'. 245 246config DM_ZERO 247 tristate "Zero target (EXPERIMENTAL)" 248 depends on BLK_DEV_DM && EXPERIMENTAL 249 ---help--- 250 A target that discards writes, and returns all zeroes for 251 reads. Useful in some recovery situations. 252 253config DM_MULTIPATH 254 tristate "Multipath target (EXPERIMENTAL)" 255 depends on BLK_DEV_DM && EXPERIMENTAL 256 ---help--- 257 Allow volume managers to support multipath hardware. 258 259config DM_MULTIPATH_EMC 260 tristate "EMC CX/AX multipath support (EXPERIMENTAL)" 261 depends on DM_MULTIPATH && BLK_DEV_DM && EXPERIMENTAL 262 ---help--- 263 Multipath support for EMC CX/AX series hardware. 264 265config DM_DELAY 266 tristate "I/O delaying target (EXPERIMENTAL)" 267 depends on BLK_DEV_DM && EXPERIMENTAL 268 ---help--- 269 A target that delays reads and/or writes and can send 270 them to different devices. Useful for testing. 271 272 If unsure, say N. 273 274endmenu 275 276endif 277