X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=drivers%2Fmd%2FKconfig;h=bf869ed03eed33c9b61c7c4c46d78e621b0e1b0e;hb=16c70f8c1b54b61c3b951b6fb220df250fe09b32;hp=a86569d2816805295bcfde08fde104e09179121c;hpb=6a77f38946aaee1cd85eeec6cf4229b204c15071;p=linux-2.6.git diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig index a86569d28..bf869ed03 100644 --- a/drivers/md/Kconfig +++ b/drivers/md/Kconfig @@ -90,10 +90,10 @@ config MD_RAID10 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 + mirroring (RAID-1) with easier configuration and more flexible layout. Unlike RAID-0, but like RAID-1, RAID-10 requires all devices to - be the same size (or atleast, only as much as the smallest device + 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. @@ -102,9 +102,10 @@ config MD_RAID10 ftp://ftp.kernel.org/pub/linux/utils/raid/mdadm/ + If unsure, say Y. -config MD_RAID5 - tristate "RAID-4/RAID-5 mode" +config MD_RAID456 + tristate "RAID-4/RAID-5/RAID-6 mode" depends on BLK_DEV_MD ---help--- A RAID-5 set of N drives with a capacity of C MB per drive provides @@ -115,42 +116,51 @@ config MD_RAID5 while a RAID-5 set distributes the parity across the drives in one of the available parity distribution methods. + 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. + Information about Software RAID on Linux is contained in the Software-RAID mini-HOWTO, available from . 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 you want to use such a RAID-4/RAID-5/RAID-6 set, say Y. To + compile this code as a module, choose M here: the module + will be called raid456. If unsure, say Y. -config MD_RAID6 - tristate "RAID-6 mode (EXPERIMENTAL)" - depends on BLK_DEV_MD && EXPERIMENTAL +config MD_RAID5_RESHAPE + bool "Support adding drives to a raid-5 array (experimental)" + depends on MD_RAID456 && EXPERIMENTAL ---help--- - WARNING: RAID-6 is currently highly experimental. If you - use it, there is no guarantee whatsoever that it won't - destroy your data, eat your disk drives, insult your mother, - or re-appoint George W. Bush. + 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. - 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: + 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. - ftp://ftp.kernel.org/pub/linux/utils/raid/mdadm/ + You will need mdadm version 2.4.1 or later to use this + feature safely. 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. - 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. + The mdadm usage is e.g. + mdadm --grow /dev/md1 --raid-disks=6 + to grow '/dev/md1' to having 6 disks. - If unsure, say N. + Note: The array can only be expanded, not contracted. + There should be enough spares already present to make the new + array workable. config MD_MULTIPATH tristate "Multipath I/O support" @@ -211,7 +221,7 @@ config DM_SNAPSHOT tristate "Snapshot target (EXPERIMENTAL)" depends on BLK_DEV_DM && EXPERIMENTAL ---help--- - Allow volume managers to take writeable snapshots of a device. + Allow volume managers to take writable snapshots of a device. config DM_MIRROR tristate "Mirror target (EXPERIMENTAL)" @@ -227,5 +237,17 @@ config DM_ZERO 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