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 (EXPERIMENTAL)" 104 depends on BLK_DEV_MD && EXPERIMENTAL 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 MD_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_RAID6_PQ 169 tristate 170 171config ASYNC_RAID6_TEST 172 tristate "Self test for hardware accelerated raid6 recovery" 173 depends on MD_RAID6_PQ 174 select ASYNC_RAID6_RECOV 175 ---help--- 176 This is a one-shot self test that permutes through the 177 recovery of all the possible two disk failure scenarios for a 178 N-disk array. Recovery is performed with the asynchronous 179 raid6 recovery routines, and will optionally use an offload 180 engine if one is available. 181 182 If unsure, say N. 183 184config MD_MULTIPATH 185 tristate "Multipath I/O support" 186 depends on BLK_DEV_MD 187 help 188 MD_MULTIPATH provides a simple multi-path personality for use 189 the MD framework. It is not under active development. New 190 projects should consider using DM_MULTIPATH which has more 191 features and more testing. 192 193 If unsure, say N. 194 195config MD_FAULTY 196 tristate "Faulty test module for MD" 197 depends on BLK_DEV_MD 198 help 199 The "faulty" module allows for a block device that occasionally returns 200 read or write errors. It is useful for testing. 201 202 In unsure, say N. 203 204config BLK_DEV_DM 205 tristate "Device mapper support" 206 ---help--- 207 Device-mapper is a low level volume manager. It works by allowing 208 people to specify mappings for ranges of logical sectors. Various 209 mapping types are available, in addition people may write their own 210 modules containing custom mappings if they wish. 211 212 Higher level volume managers such as LVM2 use this driver. 213 214 To compile this as a module, choose M here: the module will be 215 called dm-mod. 216 217 If unsure, say N. 218 219config DM_DEBUG 220 boolean "Device mapper debugging support" 221 depends on BLK_DEV_DM 222 ---help--- 223 Enable this for messages that may help debug device-mapper problems. 224 225 If unsure, say N. 226 227config DM_CRYPT 228 tristate "Crypt target support" 229 depends on BLK_DEV_DM 230 select CRYPTO 231 select CRYPTO_CBC 232 ---help--- 233 This device-mapper target allows you to create a device that 234 transparently encrypts the data on it. You'll need to activate 235 the ciphers you're going to use in the cryptoapi configuration. 236 237 Information on how to use dm-crypt can be found on 238 239 <http://www.saout.de/misc/dm-crypt/> 240 241 To compile this code as a module, choose M here: the module will 242 be called dm-crypt. 243 244 If unsure, say N. 245 246config DM_SNAPSHOT 247 tristate "Snapshot target" 248 depends on BLK_DEV_DM 249 ---help--- 250 Allow volume managers to take writable snapshots of a device. 251 252config DM_MIRROR 253 tristate "Mirror target" 254 depends on BLK_DEV_DM 255 ---help--- 256 Allow volume managers to mirror logical volumes, also 257 needed for live data migration tools such as 'pvmove'. 258 259config DM_LOG_USERSPACE 260 tristate "Mirror userspace logging (EXPERIMENTAL)" 261 depends on DM_MIRROR && EXPERIMENTAL && NET 262 select CONNECTOR 263 ---help--- 264 The userspace logging module provides a mechanism for 265 relaying the dm-dirty-log API to userspace. Log designs 266 which are more suited to userspace implementation (e.g. 267 shared storage logs) or experimental logs can be implemented 268 by leveraging this framework. 269 270config DM_ZERO 271 tristate "Zero target" 272 depends on BLK_DEV_DM 273 ---help--- 274 A target that discards writes, and returns all zeroes for 275 reads. Useful in some recovery situations. 276 277config DM_MULTIPATH 278 tristate "Multipath target" 279 depends on BLK_DEV_DM 280 # nasty syntax but means make DM_MULTIPATH independent 281 # of SCSI_DH if the latter isn't defined but if 282 # it is, DM_MULTIPATH must depend on it. We get a build 283 # error if SCSI_DH=m and DM_MULTIPATH=y 284 depends on SCSI_DH || !SCSI_DH 285 ---help--- 286 Allow volume managers to support multipath hardware. 287 288config DM_MULTIPATH_QL 289 tristate "I/O Path Selector based on the number of in-flight I/Os" 290 depends on DM_MULTIPATH 291 ---help--- 292 This path selector is a dynamic load balancer which selects 293 the path with the least number of in-flight I/Os. 294 295 If unsure, say N. 296 297config DM_MULTIPATH_ST 298 tristate "I/O Path Selector based on the service time" 299 depends on DM_MULTIPATH 300 ---help--- 301 This path selector is a dynamic load balancer which selects 302 the path expected to complete the incoming I/O in the shortest 303 time. 304 305 If unsure, say N. 306 307config DM_DELAY 308 tristate "I/O delaying target (EXPERIMENTAL)" 309 depends on BLK_DEV_DM && EXPERIMENTAL 310 ---help--- 311 A target that delays reads and/or writes and can send 312 them to different devices. Useful for testing. 313 314 If unsure, say N. 315 316config DM_UEVENT 317 bool "DM uevents (EXPERIMENTAL)" 318 depends on BLK_DEV_DM && EXPERIMENTAL 319 ---help--- 320 Generate udev events for DM events. 321 322endif # MD 323