1Redhat Linux04-磁盘管理1

Disk管理,5,InternalDisksDeviceNames,Theillustrationshowsthedisksstaticudevnames,whicharebasedonthesloteachdiskoccupies.YoucanusetheseudevnameswithstandardLinuxcommands,butdiskkernelnamesappearinfilessuchas/var/log/messagesand/proc/mdstat.,2,InternalDisksMirroringConventions,Tostandardizeandsimplifydiskadministration,mirroradiskfromoneenclosurewiththediskinthesamerelativelocationfromtheotherenclosure(forexample):/dev/sdawith/dev/sdi/dev/sdfwith/dev/sdn,3,InternalDiskManagement,UsesLinuxsoftwareRAIDforfaulttoleranceManagetheRAIDarrayswithmdadmMultipleDevicesAdminCreates,manages,andmonitorsRAIDarraysRAIDarraysare/dev/mdXXCansupportRAIDlevels1and“10”Systemssupporthotsparedisks,4,OverviewofmdadmCommand,UsedtoconfigureandmanageRAIDvolumesHasargumentstosupportthefollowingoperations:CreateRAIDarraysQueryRAIDarraysStart/stopaRAIDarrayMarkadiskasfaultyConfigurationfileis/etc/mdadm.conf,5,MirroredBootDisk,BootdiskpartitionsaremirroredatinstallationtimeBothdisksarebootableBothdiskscontaintheGRUBbootloaderDiskmirroringisperformedbyLinuxsoftware,6,DefaultBootDiskPartitionsonInternalDisks,7,ManagingPartitions,Youcanusethefdiskorsfdiskutilitiestodisplayandchangeadiskspartitiontableandgeometry(seefdisk(8)andsfdisk(8)fordetails).DuringtheLinuxoperatingsysteminstallation,allofthemirroredbootpartitionsarecreatedastype0 xfd(LinuxRAIDautodetect).Aftertheinstallation,usethefdiskcommandtoadddatadiskswiththetype0 x83(Linux).BothdisksofaRAIDpairmusthavethesamegeometry,partitiontable,andtype.,8,ThefdiskCommand,UsetocreatepartitionsondisksPartitiontablestoredinsector0ofdiskMaximumof15partitionsperdiskInternalSASdisksare/dev/sda-pPartitiondevicesare/dev/sda-p1-15Obtainsdiskgeometryautomatically,9,fdiskCommandOptions,10,fdiskCommandArguments,11,StepstoCreatingaRAID-1Array,Selectthedisks.Createanewpartitiontableandaddapartitionusingfdisk.ZerotheRAIDsuperblocks.CreateandstartaRAIDarraybyusingthemdadmcommandEnsurethattheRAIDarraysstartateachreboot.Otheractions:MakeandmountafilesystemontheRAIDarray.Addthemountpointentryto/etc/fstab.,12,Step1SelectingtheDisks,Selectapairofsame-sizeddisksandinsertthemintotwocorrespondingslotsindifferentCPU-I/Oenclosures.Thestepsinthisprocedureuse,asanexample,thediskintheleft-mostslotofthesecondrowoftheupperCPU-I/Oenclosure(theudevnameoftheslotissdb)andthelowerCPU-I/Oenclosure(theudevnameoftheslotissdj).,13,Step2CreatingaPartition,Thisexampleshowsthefdiskcommandoptionsandargumentsusedtocreateapartitiontableandaddapartition.#fdisk/dev/sdbOCreatesanewemptyDOSpartitiontable.NCreateanewpartition.Enterthefollowingactions:PCreatesaprimarypartition(useeforextendedpartition).1Specifiesthepartitionnumberyouwanttoassign.Specifiesdefaultstartingcylinder(pressEnterfordefaultvalueof1.Specifiesthelastcylindernumber(pressEnterfordefaultvalueof8924).,14,Step2CreatingaPartition(Continued),tTypethetcommand.EnterorfdEnteracceptsthedefaultID83(Linuxtype).fdselectsthetype(LinuxRAIDautodetect).pOptionally,printthepartitiontabletoverify.WWritepartitiontabletothediskandexitfsdisk.,15,Step3ZeroingtheRAIDSuperblocks,ZerotheRAIDsuperblocksoneachdisktobepairedbytypingacommandsuchasthefollowingforeachpartitiononthedisk:#mdadm-zero-superblock/dev/sdb1,16,Step4CreateandStartaRAID-1ArrayUsingmdadm,CreateandstarttheRAID-1array#mdadm-C/dev/md20-binternal-level=1-raid-devices=2/dev/sdb1/dev/sdj1The-binternaloptionimplementsRedHatLinuxRAID-1fastresync.Topreventsysteminstability,usethisoptionwhencreatingthearrayanddonotusethe-growoptionatalatertime.ViewthestatusofthenewRAID-1array#mdadm-detail/dev/md20,17,Step5EnsuringthattheRAIDArraysStartatEachReboot,Themdadm.conffilespecifieswhichRAIDarraysloadatboottime.Bydefault,itcontainsonelineforeachRAIDarraythatwascreatedduringinitialsoftwareinstallation.Addnewentriesfordatadisksthatyouadd.EachlinethatdefinesaRAIDdevicebeginswiththeARRAYkeywordOutputofthefollowingcommandprovidesthetexttoadd:#mdadm-detail-scan-verbose|grepARRAY/etc/mdadm.confSpecifyinggrepARRAYensuresthatonlytheARRAYlinesarewrittentothemdadm.conffile.,18,Step5(bandc),Youneedtoremovetheduplicateentriessothatonlyoneentryappearsforeacharray.Inatexteditor,openthe/etc/mdadm.conffileandremoveanyduplicateARRAYlines.Saveandclosethe/etc/mdadm.conffile.Executethefollowingcommandtobackuptheinitramfsramdisk,whichpreloadskernelmodulesthatarenecessarytosupporttheRAIDarraysinyoursystem.#cp/boot/initramfs-uname-r.img/boot/initramfs-uname-r-backup.imgTheuname-rcommandpassesthecurrentkernelbuildnumbertothecpcommandstring.,19,Step5(dthroughg),ExecutethefollowingcommandtorebuildtheinitramfsramdiskandmaketheRAIDarraysandmountpointspersistentacrossreboots:#dracut-force/boot/initramfs-uname-r.imguname-rExecutethefollowingcommandtorestartthekdumpservice:#servicekdumprestartExecutethefollowingcommandtoconfirmthatthekdumpserviceisrunning:#servicekdumpstatusVerifythatthekernelcommandlinedoesnotcontainrd_NO_MD.Examinetheetc/grub.conffileandifnecessaryremoverd_NO_MD.,20,Step5(h),Optionally,beforecreatingafilesystemontheRAIDarraysandcommittingdatatothem,youcanrebootthesystemtoensurethatRAIDarraysareautomaticallyassembledatboottime.Afterrebootingthesystemexecutethefollowingcommand:#mdadm-detail-scanverboseThiscommandshowsonlythecurrentlyoperationalarrays.Ifanarrayismissing,youmustrepeatthestepstocreatethearray,includingthesteptozerotheRAIDsuperblocksbeforecreatingthearray.,21,Samplemdadm.confFile,#cat/etc/mdadm.confMAILADDRrootAUTO+imsm+1.x-allARRAY/dev/md0level=raid1num-devices=2UUID=21816c38:798ab0c5:6daa9cbf:2f31005bARRAY/dev/md1level=raid1num-devices=2UUID=3a41b04c:849ca5e0:2baa1db0:1c1aaf32ARRAY/dev/md2level=raid1num-devices=2UUID=372b6dac:39b48f97:a856aad0:f58ce806ARRAY/dev/md3level=raid1num-devices=2UUID=32dcc665:fc6c02c2:4332a227:9ffc6d72ARRAY/dev/md20level=raid1num-devices=2metadata=1.2name=sys01.domain-:20UUID=9ffa9666:2212e568:498c0b6e:7e6047d0,22,MakeandMountaFileSysteminaRAIDArray,Makethefilesystemajournalingfilesystem(forexample,EXT4):#mkfs.ext4/dev/md20Makeamountpointdirectory:#mkdir/big_dataMountthefilesystem:#mount/dev/md20/mnt/big_dataAddthemounttothe/etc/fstabfile,tomountthisfilesystemeachtimethesystemboots.,23,StoppingandStartingaRAIDArray,TostopusingaRAIDarray:#umount/dev/md30#mdadm-stop/dev/md30TobeginusingaRAIDarrayagain:#mdadm-A/dev/md20#mount/dev/md30,24,ConfiguringaRAID“10”Array,RAID“10”isaRAID-0arraycomposedofRAID-1arrays.CreatetheRAID-1arrays/dev/md13,consistingofthepartitionssdb1andsdj1;and/dev/md14,consistingofthepartitionssdc1andsdk1.CreatetheRAID10array/dev/md30withthefollowingcommand:#mdadm-C/dev/md30level=0-raid-devices=2/dev/md13/dev/md14Createafilesystemofyourchoice.Addentriestothemdadm.conffile,inthefollowingorder:1stRAID-1array(forexample,md13usingsdb1andsdj1)2ndRAID-1array(forexample,md14usingsdc1andsdk1)RAID-0array(forexample,md30usingmd13andmd14)Backuptheinitramfsramdisk,executethedracutcommandandtheservicecommands.SeeslidesStep5(bandc)andStep5(dthroughg).,25,ExaminingaRAIDArray,Usemdadmcommand#mdadm-Q-detail/dev/md20ReturnsinformationaboutRAIDlevelArrayanddevicesizesNumberofdevicesSuperblockpersistenceState