1# 2# Block device driver configuration 3# 4 5menuconfig MD 6 bool "Multiple devices driver support (RAID and LVM)" 7 depends on BLOCK 8 help 9 Support multiple physical spindles through a single logical device. 10 Required for RAID and logical volume management. 11 12if MD 13 14config BLK_DEV_MD 15 tristate "RAID support" 16 ---help--- 17 This driver lets you combine several hard disk partitions into one 18 logical block device. This can be used to simply append one 19 partition to another one or to combine several redundant hard disks 20 into a RAID1/4/5 device so as to provide protection against hard 21 disk failures. This is called "Software RAID" since the combining of 22 the partitions is done by the kernel. "Hardware RAID" means that the 23 combining is done by a dedicated controller; if you have such a 24 controller, you do not need to say Y here. 25 26 More information about Software RAID on Linux is contained in the 27 Software RAID mini-HOWTO, available from 28 <http://www.tldp.org/docs.html#howto>. There you will also learn 29 where to get the supporting user space utilities raidtools. 30 31 If unsure, say N. 32 33config MD_AUTODETECT 34 bool "Autodetect RAID arrays during kernel boot" 35 depends on BLK_DEV_MD=y 36 default y 37 ---help--- 38 If you say Y here, then the kernel will try to autodetect raid 39 arrays as part of its boot process. 40 41 If you don't use raid and say Y, this autodetection can cause 42 a several-second delay in the boot time due to various 43 synchronisation steps that are part of this step. 44 45 If unsure, say Y. 46 47config MD_LINEAR 48 tristate "Linear (append) mode" 49 depends on BLK_DEV_MD 50 ---help--- 51 If you say Y here, then your multiple devices driver will be able to 52 use the so-called linear mode, i.e. it will combine the hard disk 53 partitions by simply appending one to the other. 54 55 To compile this as a module, choose M here: the module 56 will be called linear. 57 58 If unsure, say Y. 59 60config MD_RAID0 61 tristate "RAID-0 (striping) mode" 62 depends on BLK_DEV_MD 63 ---help--- 64 If you say Y here, then your multiple devices driver will be able to 65 use the so-called raid0 mode, i.e. it will combine the hard disk 66 partitions into one logical device in such a fashion as to fill them 67 up evenly, one chunk here and one chunk there. This will increase 68 the throughput rate if the partitions reside on distinct disks. 69 70 Information about Software RAID on Linux is contained in the 71 Software-RAID mini-HOWTO, available from 72 <http://www.tldp.org/docs.html#howto>. There you will also 73 learn where to get the supporting user space utilities raidtools. 74 75 To compile this as a module, choose M here: the module 76 will be called raid0. 77 78 If unsure, say Y. 79 80config MD_RAID1 81 tristate "RAID-1 (mirroring) mode" 82 depends on BLK_DEV_MD 83 ---help--- 84 A RAID-1 set consists of several disk drives which are exact copies 85 of each other. In the event of a mirror failure, the RAID driver 86 will continue to use the operational mirrors in the set, providing 87 an error free MD (multiple device) to the higher levels of the 88 kernel. In a set with N drives, the available space is the capacity 89 of a single drive, and the set protects against a failure of (N - 1) 90 drives. 91 92 Information about Software RAID on Linux is contained in the 93 Software-RAID mini-HOWTO, available from 94 <http://www.tldp.org/docs.html#howto>. There you will also 95 learn where to get the supporting user space utilities raidtools. 96 97 If you want to use such a RAID-1 set, say Y. To compile this code 98 as a module, choose M here: the module will be called raid1. 99 100 If unsure, say Y. 101 102config MD_RAID10 103 tristate "RAID-10 (mirrored striping) mode" 104 depends on BLK_DEV_MD 105 ---help--- 106 RAID-10 provides a combination of striping (RAID-0) and 107 mirroring (RAID-1) with easier configuration and more flexible 108 layout. 109 Unlike RAID-0, but like RAID-1, RAID-10 requires all devices to 110 be the same size (or at least, only as much as the smallest device 111 will be used). 112 RAID-10 provides a variety of layouts that provide different levels 113 of redundancy and performance. 114 115 RAID-10 requires mdadm-1.7.0 or later, available at: 116 117 ftp://ftp.kernel.org/pub/linux/utils/raid/mdadm/ 118 119 If unsure, say Y. 120 121config MD_RAID456 122 tristate "RAID-4/RAID-5/RAID-6 mode" 123 depends on BLK_DEV_MD 124 select RAID6_PQ 125 select ASYNC_MEMCPY 126 select ASYNC_XOR 127 select ASYNC_PQ 128 select ASYNC_RAID6_RECOV 129 ---help--- 130 A RAID-5 set of N drives with a capacity of C MB per drive provides 131 the capacity of C * (N - 1) MB, and protects against a failure 132 of a single drive. For a given sector (row) number, (N - 1) drives 133 contain data sectors, and one drive contains the parity protection. 134 For a RAID-4 set, the parity blocks are present on a single drive, 135 while a RAID-5 set distributes the parity across the drives in one 136 of the available parity distribution methods. 137 138 A RAID-6 set of N drives with a capacity of C MB per drive 139 provides the capacity of C * (N - 2) MB, and protects 140 against a failure of any two drives. For a given sector 141 (row) number, (N - 2) drives contain data sectors, and two 142 drives contains two independent redundancy syndromes. Like 143 RAID-5, RAID-6 distributes the syndromes across the drives 144 in one of the available parity distribution methods. 145 146 Information about Software RAID on Linux is contained in the 147 Software-RAID mini-HOWTO, available from 148 <http://www.tldp.org/docs.html#howto>. There you will also 149 learn where to get the supporting user space utilities raidtools. 150 151 If you want to use such a RAID-4/RAID-5/RAID-6 set, say Y. To 152 compile this code as a module, choose M here: the module 153 will be called raid456. 154 155 If unsure, say Y. 156 157config MULTICORE_RAID456 158 bool "RAID-4/RAID-5/RAID-6 Multicore processing (EXPERIMENTAL)" 159 depends on MD_RAID456 160 depends on SMP 161 depends on EXPERIMENTAL 162 ---help--- 163 Enable the raid456 module to dispatch per-stripe raid operations to a 164 thread pool. 165 166 If unsure, say N. 167 168config MD_MULTIPATH 169 tristate "Multipath I/O support" 170 depends on BLK_DEV_MD 171 help 172 MD_MULTIPATH provides a simple multi-path personality for use 173 the MD framework. It is not under active development. New 174 projects should consider using DM_MULTIPATH which has more 175 features and more testing. 176 177 If unsure, say N. 178 179config MD_FAULTY 180 tristate "Faulty test module for MD" 181 depends on BLK_DEV_MD 182 help 183 The "faulty" module allows for a block device that occasionally returns 184 read or write errors. It is useful for testing. 185 186 In unsure, say N. 187 188config BLK_DEV_DM_BUILTIN 189 boolean 190 191config BLK_DEV_DM 192 tristate "Device mapper support" 193 select BLK_DEV_DM_BUILTIN 194 ---help--- 195 Device-mapper is a low level volume manager. It works by allowing 196 people to specify mappings for ranges of logical sectors. Various 197 mapping types are available, in addition people may write their own 198 modules containing custom mappings if they wish. 199 200 Higher level volume managers such as LVM2 use this driver. 201 202 To compile this as a module, choose M here: the module will be 203 called dm-mod. 204 205 If unsure, say N. 206 207config DM_DEBUG 208 boolean "Device mapper debugging support" 209 depends on BLK_DEV_DM 210 ---help--- 211 Enable this for messages that may help debug device-mapper problems. 212 213 If unsure, say N. 214 215config DM_BUFIO 216 tristate 217 depends on BLK_DEV_DM && EXPERIMENTAL 218 ---help--- 219 This interface allows you to do buffered I/O on a device and acts 220 as a cache, holding recently-read blocks in memory and performing 221 delayed writes. 222 223source "drivers/md/persistent-data/Kconfig" 224 225config DM_CRYPT 226 tristate "Crypt target support" 227 depends on BLK_DEV_DM 228 select CRYPTO 229 select CRYPTO_CBC 230 ---help--- 231 This device-mapper target allows you to create a device that 232 transparently encrypts the data on it. You'll need to activate 233 the ciphers you're going to use in the cryptoapi configuration. 234 235 Information on how to use dm-crypt can be found on 236 237 <http://www.saout.de/misc/dm-crypt/> 238 239 To compile this code as a module, choose M here: the module will 240 be called dm-crypt. 241 242 If unsure, say N. 243 244config DM_SNAPSHOT 245 tristate "Snapshot target" 246 depends on BLK_DEV_DM 247 ---help--- 248 Allow volume managers to take writable snapshots of a device. 249 250config DM_THIN_PROVISIONING 251 tristate "Thin provisioning target (EXPERIMENTAL)" 252 depends on BLK_DEV_DM && EXPERIMENTAL 253 select DM_PERSISTENT_DATA 254 ---help--- 255 Provides thin provisioning and snapshots that share a data store. 256 257config DM_DEBUG_BLOCK_STACK_TRACING 258 boolean "Keep stack trace of thin provisioning block lock holders" 259 depends on STACKTRACE_SUPPORT && DM_THIN_PROVISIONING 260 select STACKTRACE 261 ---help--- 262 Enable this for messages that may help debug problems with the 263 block manager locking used by thin provisioning. 264 265 If unsure, say N. 266 267config DM_DEBUG_SPACE_MAPS 268 boolean "Extra validation for thin provisioning space maps" 269 depends on DM_THIN_PROVISIONING 270 ---help--- 271 Enable this for messages that may help debug problems with the 272 space maps used by thin provisioning. 273 274 If unsure, say N. 275 276config DM_MIRROR 277 tristate "Mirror target" 278 depends on BLK_DEV_DM 279 ---help--- 280 Allow volume managers to mirror logical volumes, also 281 needed for live data migration tools such as 'pvmove'. 282 283config DM_RAID 284 tristate "RAID 1/4/5/6 target" 285 depends on BLK_DEV_DM 286 select MD_RAID1 287 select MD_RAID456 288 select BLK_DEV_MD 289 ---help--- 290 A dm target that supports RAID1, RAID4, RAID5 and RAID6 mappings 291 292 A RAID-5 set of N drives with a capacity of C MB per drive provides 293 the capacity of C * (N - 1) MB, and protects against a failure 294 of a single drive. For a given sector (row) number, (N - 1) drives 295 contain data sectors, and one drive contains the parity protection. 296 For a RAID-4 set, the parity blocks are present on a single drive, 297 while a RAID-5 set distributes the parity across the drives in one 298 of the available parity distribution methods. 299 300 A RAID-6 set of N drives with a capacity of C MB per drive 301 provides the capacity of C * (N - 2) MB, and protects 302 against a failure of any two drives. For a given sector 303 (row) number, (N - 2) drives contain data sectors, and two 304 drives contains two independent redundancy syndromes. Like 305 RAID-5, RAID-6 distributes the syndromes across the drives 306 in one of the available parity distribution methods. 307 308config DM_LOG_USERSPACE 309 tristate "Mirror userspace logging (EXPERIMENTAL)" 310 depends on DM_MIRROR && EXPERIMENTAL && NET 311 select CONNECTOR 312 ---help--- 313 The userspace logging module provides a mechanism for 314 relaying the dm-dirty-log API to userspace. Log designs 315 which are more suited to userspace implementation (e.g. 316 shared storage logs) or experimental logs can be implemented 317 by leveraging this framework. 318 319config DM_ZERO 320 tristate "Zero target" 321 depends on BLK_DEV_DM 322 ---help--- 323 A target that discards writes, and returns all zeroes for 324 reads. Useful in some recovery situations. 325 326config DM_MULTIPATH 327 tristate "Multipath target" 328 depends on BLK_DEV_DM 329 # nasty syntax but means make DM_MULTIPATH independent 330 # of SCSI_DH if the latter isn't defined but if 331 # it is, DM_MULTIPATH must depend on it. We get a build 332 # error if SCSI_DH=m and DM_MULTIPATH=y 333 depends on SCSI_DH || !SCSI_DH 334 ---help--- 335 Allow volume managers to support multipath hardware. 336 337config DM_MULTIPATH_QL 338 tristate "I/O Path Selector based on the number of in-flight I/Os" 339 depends on DM_MULTIPATH 340 ---help--- 341 This path selector is a dynamic load balancer which selects 342 the path with the least number of in-flight I/Os. 343 344 If unsure, say N. 345 346config DM_MULTIPATH_ST 347 tristate "I/O Path Selector based on the service time" 348 depends on DM_MULTIPATH 349 ---help--- 350 This path selector is a dynamic load balancer which selects 351 the path expected to complete the incoming I/O in the shortest 352 time. 353 354 If unsure, say N. 355 356config DM_DELAY 357 tristate "I/O delaying target (EXPERIMENTAL)" 358 depends on BLK_DEV_DM && EXPERIMENTAL 359 ---help--- 360 A target that delays reads and/or writes and can send 361 them to different devices. Useful for testing. 362 363 If unsure, say N. 364 365config DM_UEVENT 366 bool "DM uevents" 367 depends on BLK_DEV_DM 368 ---help--- 369 Generate udev events for DM events. 370 371config DM_FLAKEY 372 tristate "Flakey target (EXPERIMENTAL)" 373 depends on BLK_DEV_DM && EXPERIMENTAL 374 ---help--- 375 A target that intermittently fails I/O for debugging purposes. 376 377config DM_VERITY 378 tristate "Verity target support (EXPERIMENTAL)" 379 depends on BLK_DEV_DM && EXPERIMENTAL 380 select CRYPTO 381 select CRYPTO_HASH 382 select DM_BUFIO 383 ---help--- 384 This device-mapper target creates a read-only device that 385 transparently validates the data on one underlying device against 386 a pre-generated tree of cryptographic checksums stored on a second 387 device. 388 389 You'll need to activate the digests you're going to use in the 390 cryptoapi configuration. 391 392 To compile this code as a module, choose M here: the module will 393 be called dm-verity. 394 395 If unsure, say N. 396 397endif # MD 398