| # |
| # Block device driver configuration |
| # |
| |
| menu "Multi-device support (RAID and LVM)" |
| |
| config MD |
| bool "Multiple devices driver support (RAID and LVM)" |
| help |
| Support multiple physical spindles through a single logical device. |
| Required for RAID and logical volume management. |
| |
| config BLK_DEV_MD |
| tristate "RAID support" |
| depends on MD |
| ---help--- |
| This driver lets you combine several hard disk partitions into one |
| logical block device. This can be used to simply append one |
| partition to another one or to combine several redundant hard disks |
| into a RAID1/4/5 device so as to provide protection against hard |
| disk failures. This is called "Software RAID" since the combining of |
| the partitions is done by the kernel. "Hardware RAID" means that the |
| combining is done by a dedicated controller; if you have such a |
| controller, you do not need to say Y here. |
| |
| More information about Software RAID on Linux is contained in the |
| Software RAID mini-HOWTO, available from |
| <http://www.tldp.org/docs.html#howto>. There you will also learn |
| where to get the supporting user space utilities raidtools. |
| |
| If unsure, say N. |
| |
| config MD_LINEAR |
| tristate "Linear (append) mode" |
| depends on BLK_DEV_MD |
| ---help--- |
| If you say Y here, then your multiple devices driver will be able to |
| use the so-called linear mode, i.e. it will combine the hard disk |
| partitions by simply appending one to the other. |
| |
| To compile this as a module, choose M here: the module |
| will be called linear. |
| |
| If unsure, say Y. |
| |
| config MD_RAID0 |
| tristate "RAID-0 (striping) mode" |
| depends on BLK_DEV_MD |
| ---help--- |
| If you say Y here, then your multiple devices driver will be able to |
| use the so-called raid0 mode, i.e. it will combine the hard disk |
| partitions into one logical device in such a fashion as to fill them |
| up evenly, one chunk here and one chunk there. This will increase |
| the throughput rate if the partitions reside on distinct disks. |
| |
| Information about Software RAID on Linux is contained in the |
| Software-RAID mini-HOWTO, available from |
| <http://www.tldp.org/docs.html#howto>. There you will also |
| learn where to get the supporting user space utilities raidtools. |
| |
| To compile this as a module, choose M here: the module |
| will be called raid0. |
| |
| If unsure, say Y. |
| |
| config MD_RAID1 |
| tristate "RAID-1 (mirroring) mode" |
| depends on BLK_DEV_MD |
| ---help--- |
| A RAID-1 set consists of several disk drives which are exact copies |
| of each other. In the event of a mirror failure, the RAID driver |
| will continue to use the operational mirrors in the set, providing |
| an error free MD (multiple device) to the higher levels of the |
| kernel. In a set with N drives, the available space is the capacity |
| of a single drive, and the set protects against a failure of (N - 1) |
| drives. |
| |
| Information about Software RAID on Linux is contained in the |
| Software-RAID mini-HOWTO, available from |
| <http://www.tldp.org/docs.html#howto>. There you will also |
| learn where to get the supporting user space utilities raidtools. |
| |
| If you want to use such a RAID-1 set, say Y. To compile this code |
| as a module, choose M here: the module will be called raid1. |
| |
| If unsure, say Y. |
| |
| config MD_RAID10 |
| tristate "RAID-10 (mirrored striping) mode (EXPERIMENTAL)" |
| depends on BLK_DEV_MD && EXPERIMENTAL |
| ---help--- |
| RAID-10 provides a combination of striping (RAID-0) and |
| mirroring (RAID-1) with easier configuration and more flexable |
| layout. |
| Unlike RAID-0, but like RAID-1, RAID-10 requires all devices to |
| be the same size (or at least, only as much as the smallest device |
| will be used). |
| RAID-10 provides a variety of layouts that provide different levels |
| of redundancy and performance. |
| |
| RAID-10 requires mdadm-1.7.0 or later, available at: |
| |
| ftp://ftp.kernel.org/pub/linux/utils/raid/mdadm/ |
| |
| If unsure, say Y. |
| |
| config MD_RAID5 |
| tristate "RAID-4/RAID-5 mode" |
| depends on BLK_DEV_MD |
| ---help--- |
| A RAID-5 set of N drives with a capacity of C MB per drive provides |
| the capacity of C * (N - 1) MB, and protects against a failure |
| of a single drive. For a given sector (row) number, (N - 1) drives |
| contain data sectors, and one drive contains the parity protection. |
| For a RAID-4 set, the parity blocks are present on a single drive, |
| while a RAID-5 set distributes the parity across the drives in one |
| of the available parity distribution methods. |
| |
| Information about Software RAID on Linux is contained in the |
| Software-RAID mini-HOWTO, available from |
| <http://www.tldp.org/docs.html#howto>. There you will also |
| learn where to get the supporting user space utilities raidtools. |
| |
| If you want to use such a RAID-4/RAID-5 set, say Y. To |
| compile this code as a module, choose M here: the module |
| will be called raid5. |
| |
| If unsure, say Y. |
| |
| config MD_RAID5_RESHAPE |
| bool "Support adding drives to a raid-5 array (experimental)" |
| depends on MD_RAID5 && EXPERIMENTAL |
| ---help--- |
| A RAID-5 set can be expanded by adding extra drives. This |
| requires "restriping" the array which means (almost) every |
| block must be written to a different place. |
| |
| This option allows such restriping to be done while the array |
| is online. However it is still EXPERIMENTAL code. It should |
| work, but please be sure that you have backups. |
| |
| You will need a version of mdadm newer than 2.3.1. During the |
| early stage of reshape there is a critical section where live data |
| is being over-written. A crash during this time needs extra care |
| for recovery. The newer mdadm takes a copy of the data in the |
| critical section and will restore it, if necessary, after a crash. |
| |
| The mdadm usage is e.g. |
| mdadm --grow /dev/md1 --raid-disks=6 |
| to grow '/dev/md1' to having 6 disks. |
| |
| Note: The array can only be expanded, not contracted. |
| There should be enough spares already present to make the new |
| array workable. |
| |
| config MD_RAID6 |
| tristate "RAID-6 mode" |
| depends on BLK_DEV_MD |
| ---help--- |
| A RAID-6 set of N drives with a capacity of C MB per drive |
| provides the capacity of C * (N - 2) MB, and protects |
| against a failure of any two drives. For a given sector |
| (row) number, (N - 2) drives contain data sectors, and two |
| drives contains two independent redundancy syndromes. Like |
| RAID-5, RAID-6 distributes the syndromes across the drives |
| in one of the available parity distribution methods. |
| |
| RAID-6 requires mdadm-1.5.0 or later, available at: |
| |
| ftp://ftp.kernel.org/pub/linux/utils/raid/mdadm/ |
| |
| If you want to use such a RAID-6 set, say Y. To compile |
| this code as a module, choose M here: the module will be |
| called raid6. |
| |
| If unsure, say Y. |
| |
| config MD_MULTIPATH |
| tristate "Multipath I/O support" |
| depends on BLK_DEV_MD |
| help |
| Multipath-IO is the ability of certain devices to address the same |
| physical disk over multiple 'IO paths'. The code ensures that such |
| paths can be defined and handled at runtime, and ensures that a |
| transparent failover to the backup path(s) happens if a IO errors |
| arrives on the primary path. |
| |
| If unsure, say N. |
| |
| config MD_FAULTY |
| tristate "Faulty test module for MD" |
| depends on BLK_DEV_MD |
| help |
| The "faulty" module allows for a block device that occasionally returns |
| read or write errors. It is useful for testing. |
| |
| In unsure, say N. |
| |
| config BLK_DEV_DM |
| tristate "Device mapper support" |
| depends on MD |
| ---help--- |
| Device-mapper is a low level volume manager. It works by allowing |
| people to specify mappings for ranges of logical sectors. Various |
| mapping types are available, in addition people may write their own |
| modules containing custom mappings if they wish. |
| |
| Higher level volume managers such as LVM2 use this driver. |
| |
| To compile this as a module, choose M here: the module will be |
| called dm-mod. |
| |
| If unsure, say N. |
| |
| config DM_CRYPT |
| tristate "Crypt target support" |
| depends on BLK_DEV_DM && EXPERIMENTAL |
| select CRYPTO |
| ---help--- |
| This device-mapper target allows you to create a device that |
| transparently encrypts the data on it. You'll need to activate |
| the ciphers you're going to use in the cryptoapi configuration. |
| |
| Information on how to use dm-crypt can be found on |
| |
| <http://www.saout.de/misc/dm-crypt/> |
| |
| To compile this code as a module, choose M here: the module will |
| be called dm-crypt. |
| |
| If unsure, say N. |
| |
| config DM_SNAPSHOT |
| tristate "Snapshot target (EXPERIMENTAL)" |
| depends on BLK_DEV_DM && EXPERIMENTAL |
| ---help--- |
| Allow volume managers to take writeable snapshots of a device. |
| |
| config DM_MIRROR |
| tristate "Mirror target (EXPERIMENTAL)" |
| depends on BLK_DEV_DM && EXPERIMENTAL |
| ---help--- |
| Allow volume managers to mirror logical volumes, also |
| needed for live data migration tools such as 'pvmove'. |
| |
| config DM_ZERO |
| tristate "Zero target (EXPERIMENTAL)" |
| depends on BLK_DEV_DM && EXPERIMENTAL |
| ---help--- |
| A target that discards writes, and returns all zeroes for |
| reads. Useful in some recovery situations. |
| |
| config DM_MULTIPATH |
| tristate "Multipath target (EXPERIMENTAL)" |
| depends on BLK_DEV_DM && EXPERIMENTAL |
| ---help--- |
| Allow volume managers to support multipath hardware. |
| |
| config DM_MULTIPATH_EMC |
| tristate "EMC CX/AX multipath support (EXPERIMENTAL)" |
| depends on DM_MULTIPATH && BLK_DEV_DM && EXPERIMENTAL |
| ---help--- |
| Multipath support for EMC CX/AX series hardware. |
| |
| endmenu |
| |