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 MD_MULTIPATH 158 tristate "Multipath I/O support" 159 depends on BLK_DEV_MD 160 help 161 MD_MULTIPATH provides a simple multi-path personality for use 162 the MD framework. It is not under active development. New 163 projects should consider using DM_MULTIPATH which has more 164 features and more testing. 165 166 If unsure, say N. 167 168config MD_FAULTY 169 tristate "Faulty test module for MD" 170 depends on BLK_DEV_MD 171 help 172 The "faulty" module allows for a block device that occasionally returns 173 read or write errors. It is useful for testing. 174 175 In unsure, say N. 176 177source "drivers/md/bcache/Kconfig" 178 179config BLK_DEV_DM 180 tristate "Device mapper support" 181 ---help--- 182 Device-mapper is a low level volume manager. It works by allowing 183 people to specify mappings for ranges of logical sectors. Various 184 mapping types are available, in addition people may write their own 185 modules containing custom mappings if they wish. 186 187 Higher level volume managers such as LVM2 use this driver. 188 189 To compile this as a module, choose M here: the module will be 190 called dm-mod. 191 192 If unsure, say N. 193 194config DM_DEBUG 195 boolean "Device mapper debugging support" 196 depends on BLK_DEV_DM 197 ---help--- 198 Enable this for messages that may help debug device-mapper problems. 199 200 If unsure, say N. 201 202config DM_BUFIO 203 tristate 204 depends on BLK_DEV_DM 205 ---help--- 206 This interface allows you to do buffered I/O on a device and acts 207 as a cache, holding recently-read blocks in memory and performing 208 delayed writes. 209 210config DM_BIO_PRISON 211 tristate 212 depends on BLK_DEV_DM 213 ---help--- 214 Some bio locking schemes used by other device-mapper targets 215 including thin provisioning. 216 217source "drivers/md/persistent-data/Kconfig" 218 219config DM_CRYPT 220 tristate "Crypt target support" 221 depends on BLK_DEV_DM 222 select CRYPTO 223 select CRYPTO_CBC 224 ---help--- 225 This device-mapper target allows you to create a device that 226 transparently encrypts the data on it. You'll need to activate 227 the ciphers you're going to use in the cryptoapi configuration. 228 229 Information on how to use dm-crypt can be found on 230 231 <http://www.saout.de/misc/dm-crypt/> 232 233 To compile this code as a module, choose M here: the module will 234 be called dm-crypt. 235 236 If unsure, say N. 237 238config DM_SNAPSHOT 239 tristate "Snapshot target" 240 depends on BLK_DEV_DM 241 ---help--- 242 Allow volume managers to take writable snapshots of a device. 243 244config DM_THIN_PROVISIONING 245 tristate "Thin provisioning target" 246 depends on BLK_DEV_DM 247 select DM_PERSISTENT_DATA 248 select DM_BIO_PRISON 249 ---help--- 250 Provides thin provisioning and snapshots that share a data store. 251 252config DM_DEBUG_BLOCK_STACK_TRACING 253 boolean "Keep stack trace of thin provisioning block lock holders" 254 depends on STACKTRACE_SUPPORT && DM_THIN_PROVISIONING 255 select STACKTRACE 256 ---help--- 257 Enable this for messages that may help debug problems with the 258 block manager locking used by thin provisioning. 259 260 If unsure, say N. 261 262config DM_CACHE 263 tristate "Cache target (EXPERIMENTAL)" 264 depends on BLK_DEV_DM 265 default n 266 select DM_PERSISTENT_DATA 267 select DM_BIO_PRISON 268 ---help--- 269 dm-cache attempts to improve performance of a block device by 270 moving frequently used data to a smaller, higher performance 271 device. Different 'policy' plugins can be used to change the 272 algorithms used to select which blocks are promoted, demoted, 273 cleaned etc. It supports writeback and writethrough modes. 274 275config DM_CACHE_MQ 276 tristate "MQ Cache Policy (EXPERIMENTAL)" 277 depends on DM_CACHE 278 default y 279 ---help--- 280 A cache policy that uses a multiqueue ordered by recent hit 281 count to select which blocks should be promoted and demoted. 282 This is meant to be a general purpose policy. It prioritises 283 reads over writes. 284 285config DM_CACHE_CLEANER 286 tristate "Cleaner Cache Policy (EXPERIMENTAL)" 287 depends on DM_CACHE 288 default y 289 ---help--- 290 A simple cache policy that writes back all data to the 291 origin. Used when decommissioning a dm-cache. 292 293config DM_MIRROR 294 tristate "Mirror target" 295 depends on BLK_DEV_DM 296 ---help--- 297 Allow volume managers to mirror logical volumes, also 298 needed for live data migration tools such as 'pvmove'. 299 300config DM_LOG_USERSPACE 301 tristate "Mirror userspace logging" 302 depends on DM_MIRROR && NET 303 select CONNECTOR 304 ---help--- 305 The userspace logging module provides a mechanism for 306 relaying the dm-dirty-log API to userspace. Log designs 307 which are more suited to userspace implementation (e.g. 308 shared storage logs) or experimental logs can be implemented 309 by leveraging this framework. 310 311config DM_RAID 312 tristate "RAID 1/4/5/6/10 target" 313 depends on BLK_DEV_DM 314 select MD_RAID1 315 select MD_RAID10 316 select MD_RAID456 317 select BLK_DEV_MD 318 ---help--- 319 A dm target that supports RAID1, RAID10, RAID4, RAID5 and RAID6 mappings 320 321 A RAID-5 set of N drives with a capacity of C MB per drive provides 322 the capacity of C * (N - 1) MB, and protects against a failure 323 of a single drive. For a given sector (row) number, (N - 1) drives 324 contain data sectors, and one drive contains the parity protection. 325 For a RAID-4 set, the parity blocks are present on a single drive, 326 while a RAID-5 set distributes the parity across the drives in one 327 of the available parity distribution methods. 328 329 A RAID-6 set of N drives with a capacity of C MB per drive 330 provides the capacity of C * (N - 2) MB, and protects 331 against a failure of any two drives. For a given sector 332 (row) number, (N - 2) drives contain data sectors, and two 333 drives contains two independent redundancy syndromes. Like 334 RAID-5, RAID-6 distributes the syndromes across the drives 335 in one of the available parity distribution methods. 336 337config DM_ZERO 338 tristate "Zero target" 339 depends on BLK_DEV_DM 340 ---help--- 341 A target that discards writes, and returns all zeroes for 342 reads. Useful in some recovery situations. 343 344config DM_MULTIPATH 345 tristate "Multipath target" 346 depends on BLK_DEV_DM 347 # nasty syntax but means make DM_MULTIPATH independent 348 # of SCSI_DH if the latter isn't defined but if 349 # it is, DM_MULTIPATH must depend on it. We get a build 350 # error if SCSI_DH=m and DM_MULTIPATH=y 351 depends on SCSI_DH || !SCSI_DH 352 ---help--- 353 Allow volume managers to support multipath hardware. 354 355config DM_MULTIPATH_QL 356 tristate "I/O Path Selector based on the number of in-flight I/Os" 357 depends on DM_MULTIPATH 358 ---help--- 359 This path selector is a dynamic load balancer which selects 360 the path with the least number of in-flight I/Os. 361 362 If unsure, say N. 363 364config DM_MULTIPATH_ST 365 tristate "I/O Path Selector based on the service time" 366 depends on DM_MULTIPATH 367 ---help--- 368 This path selector is a dynamic load balancer which selects 369 the path expected to complete the incoming I/O in the shortest 370 time. 371 372 If unsure, say N. 373 374config DM_DELAY 375 tristate "I/O delaying target" 376 depends on BLK_DEV_DM 377 ---help--- 378 A target that delays reads and/or writes and can send 379 them to different devices. Useful for testing. 380 381 If unsure, say N. 382 383config DM_UEVENT 384 bool "DM uevents" 385 depends on BLK_DEV_DM 386 ---help--- 387 Generate udev events for DM events. 388 389config DM_FLAKEY 390 tristate "Flakey target" 391 depends on BLK_DEV_DM 392 ---help--- 393 A target that intermittently fails I/O for debugging purposes. 394 395config DM_VERITY 396 tristate "Verity target support" 397 depends on BLK_DEV_DM 398 select CRYPTO 399 select CRYPTO_HASH 400 select DM_BUFIO 401 ---help--- 402 This device-mapper target creates a read-only device that 403 transparently validates the data on one underlying device against 404 a pre-generated tree of cryptographic checksums stored on a second 405 device. 406 407 You'll need to activate the digests you're going to use in the 408 cryptoapi configuration. 409 410 To compile this code as a module, choose M here: the module will 411 be called dm-verity. 412 413 If unsure, say N. 414 415config DM_SWITCH 416 tristate "Switch target support (EXPERIMENTAL)" 417 depends on BLK_DEV_DM 418 ---help--- 419 This device-mapper target creates a device that supports an arbitrary 420 mapping of fixed-size regions of I/O across a fixed set of paths. 421 The path used for any specific region can be switched dynamically 422 by sending the target a message. 423 424 To compile this code as a module, choose M here: the module will 425 be called dm-switch. 426 427 If unsure, say N. 428 429endif # MD 430