Comprehensive use of RAID and LVM in linux !, Raidlvm

Comprehensive use of RAID and LVM in linux !, Raidlvm

The LVM can elastically adjust the filesystem size, but the disadvantage is that it may not have the acceleration and hardware backup (unlike snapshot) functions. Disk arrays provide performance and backup functions, but cannot provide advantages similar to LVM. In this situation, we want to use the "build LVM on RAID" function to achieve both capabilities.

Objective: To test the architecture of an LVM system on a RAID disk;
Requirement: requires disk management capabilities, including RAID and LVM;
What should we do? The following procedure is a step-by-step implementation:

1. When restoring the system, you must:
Unmount the previously mounted file system with umount;
Modify the data in/etc/fstab so that it will not be automatically mounted upon startup;

Fdisk is used to split the split slot.

In the end, your system should only look like the following: (/dev/sd {B, c, d, e, f} are all formatted as ext3 using mkds)

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Disk/dev/sdb: 8589 MB, 8589934592bytes255heads, 63 sectors/track, 1044 cylinders

Units = cylindersof16065 * 512 = 8225280 bytes

Disk/dev/sdbdoesn 'tcontainavalidpartitiontable

Disk/dev/sdc: 8589 MB, 8589934592bytes255heads, 63 sectors/track, 1044 cylinders

Units = cylindersof16065 * 512 = 8225280 bytes

Disk/dev/sdcdoesn 'tcontainavalidpartitiontable

Disk/dev/sdd: 8589 MB, 8589934592bytes255heads, 63 sectors/track, 1044 cylinders

Units = cylindersof16065 * 512 = 8225280 bytes

Disk/dev/sdddoesn 'tcontainavalidpartitiontable

Disk/dev/sde: 8589 MB, 8589934592bytes255heads, 63 sectors/track, 1044 cylinders

Units = cylindersof16065 * 512 = 8225280 bytes

Disk/dev/sdedoesn 'tcontainavalidpartitiontable

Disk/dev/sdf: 8589 MB, 8589934592bytes255heads, 63 sectors/track, 1044 cylinders

Units = cylindersof16065 * 512 = 8225280 bytes

Disk/dev/sdfdoesn 'tcontainavalidpartitiontable
2. Create a RAID. Assume that we use five (/dev/sd {B, c, d, e, f}) 8 GB split slots to create a RAID-5, and has a spare disk
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[Root @ linux ~] # Mdadm -- create -- auto = yes/dev/md0 -- level = 5 -- raid-devices = 4 -- spare-devices = 1/dev/sd {B, c, d, e, f} mdadm:/dev/sdbappearstocontainanext2fsfilesystem

Size = 8388608 Kmtime = ThuJan108: 00: 001970 mdadm:/dev/sdcappearstocontainanext2fsfilesystem

Size = 8388608 Kmtime = ThuJan108: 00: 001970 mdadm:/dev/sddappearstocontainanext2fsfilesystem

Size = 8388608 Kmtime = ThuJan108: 00: 001970 mdadm:/dev/sdeappearstocontainanext2fsfilesystem

Size = 8388608 Kmtime = ThuJan108: 00: 001970 mdadm:/dev/sdfappearstocontainanext2fsfilesystem

Size = 8388608 Kmtime = ThuJan108: 00: 001970 Continuecreatingarrayy

Mdadm: array/dev/md0started.
3. Start to process LVM. Now we assume that all the parameters use the default value, including PE, and VG is named raidvg and LV is named raidlv. The basic process is as follows:[Cpp]View plain copy

[Root @ linux ~] # Pvcreate/dev/md0Physicalvolume "/dev/md0" successfullycreated

[Root @ linux ~] # Vgcreateraidvg/dev/md0/dev/cdrom: openfailed: Read-Only File System

Attempttoclosedevice '/dev/cdrom' whichisnotopen./dev/cdrom: openfailed: Read-Only File System

Attempttoclosedevice '/dev/cdrom' whichisnotopen. Volumegroup "raidvg" successfullycreated

[Root @ linux ~] # Lvcreate-l6143-nraidlvraidvgLogicalvolume "raidlv" created

[Root @ linux ~] # Lvdisplay --- Logicalvolume ---

LVName/dev/raidvg/raidlvVGNameraidvg

LVUUIDrBySS0-JxZ6-ANYe-Vp8G-xlUd-Rz1x-G6NjnTLVWriteAccessread/write

LVStatusavailable # open0

LVSize24.00GBCurrentLE6143

Segments1Allocationinherit

Readaheadsectorsauto-currentlysetto768

Blockdevice253: 0
4. Mount[Cpp]View plain copy

[Root @ linux ~] # Mkdir/mnt/raidlvm [root @ linux ~] # Mkfs-text3/dev/raidvg/raidlv

Mke2fs1.39 (29-May-2006) Filesystemlabel =

OStype: LinuxBlocksize = 4096 (log = 2)

Fragmentsize = 4096 (log = 2) 3145728 inodes, 6290432 blocks

314521 blocks (5.00%) reservedforthesuperuserFirstdatablock = 0

Maximumfilesystemblocks = 0192 blockgroups

32768 blockspergroup, 32768fragmentspergroup16384inodespergroup

Superblockbackupsstoredonblocks: 32768,98304, 163840,229376, 294912,819200, 884736,1605632, 2654208,

4096000

Writinginodetables: doneCreatingjournal (32768 blocks): done

Writingsuperblocksandfilesystemaccountinginformation: done

Thisfilesystemwillbeautomaticallycheckedevery21mountsor180days, whichevercomesfirst. Usetune2fs-cor-itooverride.

[Root @ linux ~] # Mount/dev/raidvg/raidlv/mnt/raidlvm/
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[Root @ linuxraidlvm] # mdadm -- detail/dev/md0 | grepUUIDUUID: 99de722a: bfd56556: 7b4248e1: 3bf3f4f9

[Root @ linuxraidlvm] # cat/etc/mdadm. confARRAY/dev/md0UUID = 99de722a: bfd56556: 7b4248e1: 3bf3f4f9

[Root @ linuxraidlvm] # cat/etc/fstab | grep/mnt/raidlvm/dev/raidvg/raidlv/mnt/raidlvmext3defaults126, check[Cpp]View plain copy

[Root @ linuxraidlvm] # mdadm -- detail/dev/md0/dev/md0:

Version: 0.90 CreationTime: FriFeb1722: 26: 442012

RaidLevel: raid5ArraySize: 25165632 (24.00GiB25.77GB)

UsedDevSize: 8388544 (8.00GiB8.59GB) RaidDevices: 4

TotalDevices: 5 PreferredMinor: 0

Persistence: Superblockispersistent

UpdateTime: Maid: 39: 112012 State: clean

ActiveDevices: 4 WorkingDevices: 5

FailedDevices: 0 SpareDevices: 1

Layout: left-lateral ric

ChunkSize: 64 K

UUID: 99de722a: bfd56556: 7b4248e1: 3bf3f4f9Events: 0.2

NumberMajorMinorRaidDeviceState

08160 activesync/dev/sdb18321activesync/dev/sdc

28482 activesync/dev/sdd38643activesync/dev/sde

4880-spare/dev/sdf

[Root @ linuxraidlvm] # cat/proc/mdstatPersonalities: [raid6] [raid5] [raid4]

Md0: activeraid5sde [3] sdf [4] (S) sdd [2] sdc [1] sdb [0] 25165632blockslevel5, 64 kchunk, algorithm2 [4/4] [UUUU]

Unuseddevices:

[Root @ linuxraidlvm] # pvscan/dev/cdrom: openfailed: Read-Only File System

Attempttoclosedevice '/dev/cdrom' whichisnotopen. PV/dev/md0VGraidvglvm2 [24.00 GB/0 free]

Total: 1 [24.00 GB]/inuse: 1 [24.00 GB]/innoVG: 0 [0] [root @ linuxraidlvm] # pvdisplay

--- Physicalvolume --- PVName/dev/md0

VGNameraidvgPVSize24.00GB/notusable3.81MB

Allocatableyes (butfull) PESize (KByte) 4096

TotalPE6143FreePE0

AllocatedPE6143PVUUIDKgwVH9-HwTG-q4it-z0Ps-ACac-Si1y-8RxTkx

[Root @ linuxraidlvm] # vgscan

Readingallphysicalvolumes. Thismaytakeawhile.../dev/cdrom: openfailed: Read-Only File System

Attempttoclosedevice '/dev/cdrom' whichisnotopen. Foundvolumegroup "raidvg" usingmetadatatypelvm2

[Root @ linuxraidlvm] # vgdisplay --- Volumegroup ---

VGNameraidvgSystemID

Formatlvm2MetadataAreas1

MetadataSequenceNo2VGAccessread/write

VGStatusresizableMAXLV0

CurLV1OpenLV1

MaxPV0CurPV1

ActPV1VGSize24.00GB

PESize4.00MBTotalPE6143

AllocPE/Size6143/24.00 GBFreePE/Size0/0

VGUUIDzlM0TJ-fjR0-b2kO-rCpO-D6L9-zw0m-W3SVzp

[Root @ linuxraidlvm] # lvscanACTIVE '/dev/raidvg/raidlv' [24.00 GB] inherit

[Root @ linuxraidlvm] # lvdisplay --- Logicalvolume ---

LVName/dev/raidvg/raidlvVGNameraidvg

LVUUIDrBySS0-JxZ6-ANYe-Vp8G-xlUd-Rz1x-G6NjnTLVWriteAccessread/write

LVStatusavailable # open1

LVSize24.00GBCurrentLE6143

Segments1Allocationinherit

Readaheadsectorsauto-currentlysetto768

Blockdevice253: 0 [root @ linux ~] # Df

File System 1 K-available block used % mount point/dev/sda359912322662984301900047 %/

/Dev/sda1101086113738449412 %/boottmpfs51754805175480 %/dev/shm

/Dev/mapper/raidvg-raidlv24766844176204233325561 %/mnt/raidlvm

[Root @ linux ~] # Cd/mnt/raidlvm/[root @ linuxraidlvm] # ll

Total 20drwx ------ 2rootroot1638402-1722: 37 lost + found

-Rw-r -- 1rootroot602-1722: 38tt [root @ linuxraidlvm] # cattt