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author | Neil Brown <neilb@suse.de> | 2002-03-15 05:21:36 +0000 |
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committer | Neil Brown <neilb@suse.de> | 2002-03-15 05:21:36 +0000 |
commit | 56eb10c0b6e8f21540af444c8a28aa9e8f138ce6 (patch) | |
tree | 3b791ce573cca8c746f318411cb63d8c677678a1 /md.man | |
parent | 9a9dab3670110c2db7fe6f716977b72adedbf855 (diff) | |
download | mdadm-56eb10c0b6e8f21540af444c8a28aa9e8f138ce6.tar.gz mdadm-56eb10c0b6e8f21540af444c8a28aa9e8f138ce6.tar.xz mdadm-56eb10c0b6e8f21540af444c8a28aa9e8f138ce6.zip |
mdadm-0.7.1mdadm-0.7.1
Diffstat (limited to 'md.man')
-rw-r--r-- | md.man | 89 |
1 files changed, 89 insertions, 0 deletions
@@ -0,0 +1,89 @@ +MD(4) MD(4) + + + +NNAAMMEE + md - Multiple Device driver aka Linux Software Raid + +SSYYNNOOPPSSIISS + //ddeevv//mmdd_n + //ddeevv//mmdd//_n + +DDEESSCCRRIIPPTTIIOONN + The mmdd driver provides virtual devices that are created + from one or more independant underlying devices. This + array of devices often contains redundancy, and hence the + acronym RAID which stands for a Redundant Array of Inde- + pendant Devices. + + mmdd support RAID levels 1 (mirroring) 4 (striped array with + parity device) and 5 (striped array with distributed par- + ity information. If a single underlying device fails + while using one of these level, they array will continue + to function. + + mmdd also supports a number of pseudo RAID (non-redundant) + configuations including RAID0 (striped array), LINEAR + (catenated array) and MULTIPATH (a set of different inter- + faces to the same device). + + + RRAAIIDD SSUUPPEERR BBLLOOCCKK + With the exception of Legacy Arrays described below, each + device that is incorportated into an MD array has a _s_u_p_e_r + _b_l_o_c_k written towards the end of the device. This + superblock records information about the structure and + state of the array so that the array an be reliably re- + assembled after a shutdown. + + The superblock is 4K long and is written into a 64K + aligned block that start at least 64K and less than 128K + from the end of the device (i.e. to get the address of the + superblock round the size of the device down to a multiple + of 64K and then subtract 64K). The available size of each + device is the ammount of space before the super block, so + between 64K and 128K is lost when a device in incorporated + into an MD array. + + The superblock contains, among other things: + + LEVEL The + + UUID a 128 bit Universally Unique Identifier that iden- + tifies the array that this device is part of. + + + LLIINNEEAARR + RRAAIIDD00 + RRAAIIDD11 + RRAAIIDD44 + RRAAIIDD55 + RREEBBUUIILLDD//RREESSYYNNCC +FFIILLEESS + //pprroocc//mmddssttaatt + Contains information about the status of currently + running array. + + //pprroocc//ssyyss//ddeevv//rraaiidd//ssppeeeedd__lliimmiitt__mmiinn + A readable and writable file that reflects the cur- + rent goal rebuild speed for times when non-rebuild + activity is current on an array. The speed is in + Kibibytes per second, and is a per-device rate, not + a per-array rate (which means that an array with + more disc will shuffle more data for a given + speed). The default is 100. + + + //pprroocc//ssyyss//ddeevv//rraaiidd//ssppeeeedd__lliimmiitt__mmaaxx + A readable and writable file that reflects the cur- + rent goal rebuild speed for times when no non- + rebuild activity is current on an array. The + default is 100,000. + + +SSEEEE AALLSSOO + mmddaaddmm(8), mmkkrraaiidd(8). + + + + MD(4) |