1# 2# Block device driver configuration 3# 4 5menuconfig MD 6 bool "Multiple devices driver support (RAID and LVM)" 7 depends on BLOCK 8 select SRCU 9 help 10 Support multiple physical spindles through a single logical device. 11 Required for RAID and logical volume management. 12 13if MD 14 15config BLK_DEV_MD 16 tristate "RAID support" 17 ---help--- 18 This driver lets you combine several hard disk partitions into one 19 logical block device. This can be used to simply append one 20 partition to another one or to combine several redundant hard disks 21 into a RAID1/4/5 device so as to provide protection against hard 22 disk failures. This is called "Software RAID" since the combining of 23 the partitions is done by the kernel. "Hardware RAID" means that the 24 combining is done by a dedicated controller; if you have such a 25 controller, you do not need to say Y here. 26 27 More information about Software RAID on Linux is contained in the 28 Software RAID mini-HOWTO, available from 29 <http://www.tldp.org/docs.html#howto>. There you will also learn 30 where to get the supporting user space utilities raidtools. 31 32 If unsure, say N. 33 34config MD_AUTODETECT 35 bool "Autodetect RAID arrays during kernel boot" 36 depends on BLK_DEV_MD=y 37 default y 38 ---help--- 39 If you say Y here, then the kernel will try to autodetect raid 40 arrays as part of its boot process. 41 42 If you don't use raid and say Y, this autodetection can cause 43 a several-second delay in the boot time due to various 44 synchronisation steps that are part of this step. 45 46 If unsure, say Y. 47 48config MD_LINEAR 49 tristate "Linear (append) 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 linear mode, i.e. it will combine the hard disk 54 partitions by simply appending one to the other. 55 56 To compile this as a module, choose M here: the module 57 will be called linear. 58 59 If unsure, say Y. 60 61config MD_RAID0 62 tristate "RAID-0 (striping) mode" 63 depends on BLK_DEV_MD 64 ---help--- 65 If you say Y here, then your multiple devices driver will be able to 66 use the so-called raid0 mode, i.e. it will combine the hard disk 67 partitions into one logical device in such a fashion as to fill them 68 up evenly, one chunk here and one chunk there. This will increase 69 the throughput rate if the partitions reside on distinct disks. 70 71 Information about Software RAID on Linux is contained in the 72 Software-RAID mini-HOWTO, available from 73 <http://www.tldp.org/docs.html#howto>. There you will also 74 learn where to get the supporting user space utilities raidtools. 75 76 To compile this as a module, choose M here: the module 77 will be called raid0. 78 79 If unsure, say Y. 80 81config MD_RAID1 82 tristate "RAID-1 (mirroring) mode" 83 depends on BLK_DEV_MD 84 ---help--- 85 A RAID-1 set consists of several disk drives which are exact copies 86 of each other. In the event of a mirror failure, the RAID driver 87 will continue to use the operational mirrors in the set, providing 88 an error free MD (multiple device) to the higher levels of the 89 kernel. In a set with N drives, the available space is the capacity 90 of a single drive, and the set protects against a failure of (N - 1) 91 drives. 92 93 Information about Software RAID on Linux is contained in the 94 Software-RAID mini-HOWTO, available from 95 <http://www.tldp.org/docs.html#howto>. There you will also 96 learn where to get the supporting user space utilities raidtools. 97 98 If you want to use such a RAID-1 set, say Y. To compile this code 99 as a module, choose M here: the module will be called raid1. 100 101 If unsure, say Y. 102 103config MD_RAID10 104 tristate "RAID-10 (mirrored striping) mode" 105 depends on BLK_DEV_MD 106 ---help--- 107 RAID-10 provides a combination of striping (RAID-0) and 108 mirroring (RAID-1) with easier configuration and more flexible 109 layout. 110 Unlike RAID-0, but like RAID-1, RAID-10 requires all devices to 111 be the same size (or at least, only as much as the smallest device 112 will be used). 113 RAID-10 provides a variety of layouts that provide different levels 114 of redundancy and performance. 115 116 RAID-10 requires mdadm-1.7.0 or later, available at: 117 118 ftp://ftp.kernel.org/pub/linux/utils/raid/mdadm/ 119 120 If unsure, say Y. 121 122config MD_RAID456 123 tristate "RAID-4/RAID-5/RAID-6 mode" 124 depends on BLK_DEV_MD 125 select RAID6_PQ 126 select ASYNC_MEMCPY 127 select ASYNC_XOR 128 select ASYNC_PQ 129 select ASYNC_RAID6_RECOV 130 ---help--- 131 A RAID-5 set of N drives with a capacity of C MB per drive provides 132 the capacity of C * (N - 1) MB, and protects against a failure 133 of a single drive. For a given sector (row) number, (N - 1) drives 134 contain data sectors, and one drive contains the parity protection. 135 For a RAID-4 set, the parity blocks are present on a single drive, 136 while a RAID-5 set distributes the parity across the drives in one 137 of the available parity distribution methods. 138 139 A RAID-6 set of N drives with a capacity of C MB per drive 140 provides the capacity of C * (N - 2) MB, and protects 141 against a failure of any two drives. For a given sector 142 (row) number, (N - 2) drives contain data sectors, and two 143 drives contains two independent redundancy syndromes. Like 144 RAID-5, RAID-6 distributes the syndromes across the drives 145 in one of the available parity distribution methods. 146 147 Information about Software RAID on Linux is contained in the 148 Software-RAID mini-HOWTO, available from 149 <http://www.tldp.org/docs.html#howto>. There you will also 150 learn where to get the supporting user space utilities raidtools. 151 152 If you want to use such a RAID-4/RAID-5/RAID-6 set, say Y. To 153 compile this code as a module, choose M here: the module 154 will be called raid456. 155 156 If unsure, say Y. 157 158config MD_MULTIPATH 159 tristate "Multipath I/O support" 160 depends on BLK_DEV_MD 161 help 162 MD_MULTIPATH provides a simple multi-path personality for use 163 the MD framework. It is not under active development. New 164 projects should consider using DM_MULTIPATH which has more 165 features and more testing. 166 167 If unsure, say N. 168 169config MD_FAULTY 170 tristate "Faulty test module for MD" 171 depends on BLK_DEV_MD 172 help 173 The "faulty" module allows for a block device that occasionally returns 174 read or write errors. It is useful for testing. 175 176 In unsure, say N. 177 178source "drivers/md/bcache/Kconfig" 179 180config BLK_DEV_DM_BUILTIN 181 boolean 182 183config BLK_DEV_DM 184 tristate "Device mapper support" 185 select BLK_DEV_DM_BUILTIN 186 ---help--- 187 Device-mapper is a low level volume manager. It works by allowing 188 people to specify mappings for ranges of logical sectors. Various 189 mapping types are available, in addition people may write their own 190 modules containing custom mappings if they wish. 191 192 Higher level volume managers such as LVM2 use this driver. 193 194 To compile this as a module, choose M here: the module will be 195 called dm-mod. 196 197 If unsure, say N. 198 199config DM_DEBUG 200 boolean "Device mapper debugging support" 201 depends on BLK_DEV_DM 202 ---help--- 203 Enable this for messages that may help debug device-mapper problems. 204 205 If unsure, say N. 206 207config DM_BUFIO 208 tristate 209 depends on BLK_DEV_DM 210 ---help--- 211 This interface allows you to do buffered I/O on a device and acts 212 as a cache, holding recently-read blocks in memory and performing 213 delayed writes. 214 215config DM_BIO_PRISON 216 tristate 217 depends on BLK_DEV_DM 218 ---help--- 219 Some bio locking schemes used by other device-mapper targets 220 including thin provisioning. 221 222source "drivers/md/persistent-data/Kconfig" 223 224config DM_CRYPT 225 tristate "Crypt target support" 226 depends on BLK_DEV_DM 227 select CRYPTO 228 select CRYPTO_CBC 229 ---help--- 230 This device-mapper target allows you to create a device that 231 transparently encrypts the data on it. You'll need to activate 232 the ciphers you're going to use in the cryptoapi configuration. 233 234 Information on how to use dm-crypt can be found on 235 236 <http://www.saout.de/misc/dm-crypt/> 237 238 To compile this code as a module, choose M here: the module will 239 be called dm-crypt. 240 241 If unsure, say N. 242 243config DM_SNAPSHOT 244 tristate "Snapshot target" 245 depends on BLK_DEV_DM 246 select DM_BUFIO 247 ---help--- 248 Allow volume managers to take writable snapshots of a device. 249 250config DM_THIN_PROVISIONING 251 tristate "Thin provisioning target" 252 depends on BLK_DEV_DM 253 select DM_PERSISTENT_DATA 254 select DM_BIO_PRISON 255 ---help--- 256 Provides thin provisioning and snapshots that share a data store. 257 258config DM_CACHE 259 tristate "Cache target (EXPERIMENTAL)" 260 depends on BLK_DEV_DM 261 default n 262 select DM_PERSISTENT_DATA 263 select DM_BIO_PRISON 264 ---help--- 265 dm-cache attempts to improve performance of a block device by 266 moving frequently used data to a smaller, higher performance 267 device. Different 'policy' plugins can be used to change the 268 algorithms used to select which blocks are promoted, demoted, 269 cleaned etc. It supports writeback and writethrough modes. 270 271config DM_CACHE_MQ 272 tristate "MQ Cache Policy (EXPERIMENTAL)" 273 depends on DM_CACHE 274 default y 275 ---help--- 276 A cache policy that uses a multiqueue ordered by recent hit 277 count to select which blocks should be promoted and demoted. 278 This is meant to be a general purpose policy. It prioritises 279 reads over writes. 280 281config DM_CACHE_CLEANER 282 tristate "Cleaner Cache Policy (EXPERIMENTAL)" 283 depends on DM_CACHE 284 default y 285 ---help--- 286 A simple cache policy that writes back all data to the 287 origin. Used when decommissioning a dm-cache. 288 289config DM_ERA 290 tristate "Era target (EXPERIMENTAL)" 291 depends on BLK_DEV_DM 292 default n 293 select DM_PERSISTENT_DATA 294 select DM_BIO_PRISON 295 ---help--- 296 dm-era tracks which parts of a block device are written to 297 over time. Useful for maintaining cache coherency when using 298 vendor snapshots. 299 300config DM_MIRROR 301 tristate "Mirror target" 302 depends on BLK_DEV_DM 303 ---help--- 304 Allow volume managers to mirror logical volumes, also 305 needed for live data migration tools such as 'pvmove'. 306 307config DM_LOG_USERSPACE 308 tristate "Mirror userspace logging" 309 depends on DM_MIRROR && NET 310 select CONNECTOR 311 ---help--- 312 The userspace logging module provides a mechanism for 313 relaying the dm-dirty-log API to userspace. Log designs 314 which are more suited to userspace implementation (e.g. 315 shared storage logs) or experimental logs can be implemented 316 by leveraging this framework. 317 318config DM_RAID 319 tristate "RAID 1/4/5/6/10 target" 320 depends on BLK_DEV_DM 321 select MD_RAID1 322 select MD_RAID10 323 select MD_RAID456 324 select BLK_DEV_MD 325 ---help--- 326 A dm target that supports RAID1, RAID10, RAID4, RAID5 and RAID6 mappings 327 328 A RAID-5 set of N drives with a capacity of C MB per drive provides 329 the capacity of C * (N - 1) MB, and protects against a failure 330 of a single drive. For a given sector (row) number, (N - 1) drives 331 contain data sectors, and one drive contains the parity protection. 332 For a RAID-4 set, the parity blocks are present on a single drive, 333 while a RAID-5 set distributes the parity across the drives in one 334 of the available parity distribution methods. 335 336 A RAID-6 set of N drives with a capacity of C MB per drive 337 provides the capacity of C * (N - 2) MB, and protects 338 against a failure of any two drives. For a given sector 339 (row) number, (N - 2) drives contain data sectors, and two 340 drives contains two independent redundancy syndromes. Like 341 RAID-5, RAID-6 distributes the syndromes across the drives 342 in one of the available parity distribution methods. 343 344config DM_ZERO 345 tristate "Zero target" 346 depends on BLK_DEV_DM 347 ---help--- 348 A target that discards writes, and returns all zeroes for 349 reads. Useful in some recovery situations. 350 351config DM_MULTIPATH 352 tristate "Multipath target" 353 depends on BLK_DEV_DM 354 # nasty syntax but means make DM_MULTIPATH independent 355 # of SCSI_DH if the latter isn't defined but if 356 # it is, DM_MULTIPATH must depend on it. We get a build 357 # error if SCSI_DH=m and DM_MULTIPATH=y 358 depends on SCSI_DH || !SCSI_DH 359 ---help--- 360 Allow volume managers to support multipath hardware. 361 362config DM_MULTIPATH_QL 363 tristate "I/O Path Selector based on the number of in-flight I/Os" 364 depends on DM_MULTIPATH 365 ---help--- 366 This path selector is a dynamic load balancer which selects 367 the path with the least number of in-flight I/Os. 368 369 If unsure, say N. 370 371config DM_MULTIPATH_ST 372 tristate "I/O Path Selector based on the service time" 373 depends on DM_MULTIPATH 374 ---help--- 375 This path selector is a dynamic load balancer which selects 376 the path expected to complete the incoming I/O in the shortest 377 time. 378 379 If unsure, say N. 380 381config DM_DELAY 382 tristate "I/O delaying target" 383 depends on BLK_DEV_DM 384 ---help--- 385 A target that delays reads and/or writes and can send 386 them to different devices. Useful for testing. 387 388 If unsure, say N. 389 390config DM_UEVENT 391 bool "DM uevents" 392 depends on BLK_DEV_DM 393 ---help--- 394 Generate udev events for DM events. 395 396config DM_FLAKEY 397 tristate "Flakey target" 398 depends on BLK_DEV_DM 399 ---help--- 400 A target that intermittently fails I/O for debugging purposes. 401 402config DM_VERITY 403 tristate "Verity target support" 404 depends on BLK_DEV_DM 405 select CRYPTO 406 select CRYPTO_HASH 407 select DM_BUFIO 408 ---help--- 409 This device-mapper target creates a read-only device that 410 transparently validates the data on one underlying device against 411 a pre-generated tree of cryptographic checksums stored on a second 412 device. 413 414 You'll need to activate the digests you're going to use in the 415 cryptoapi configuration. 416 417 To compile this code as a module, choose M here: the module will 418 be called dm-verity. 419 420 If unsure, say N. 421 422config DM_SWITCH 423 tristate "Switch target support (EXPERIMENTAL)" 424 depends on BLK_DEV_DM 425 ---help--- 426 This device-mapper target creates a device that supports an arbitrary 427 mapping of fixed-size regions of I/O across a fixed set of paths. 428 The path used for any specific region can be switched dynamically 429 by sending the target a message. 430 431 To compile this code as a module, choose M here: the module will 432 be called dm-switch. 433 434 If unsure, say N. 435 436endif # MD 437