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