在windows操作系统中，硬盘有fat32和ntfs等多种格式。在linux中同样如此。CentOS 6之前，主要是ext4、ext3和ext2等格式。在CentOS 7这个版本开始，默认的磁盘格式变成了xfs格式。
[root@server02~]#cat/etc/filesystems xfs ext4 ext3 ext2 nodevproc nodevdevpts iso9660 vfat hfs hfsplus * [root@server02~]#mount//查看分区的文件系统类型，需要挂载才能看见 sysfson/systypesysfs(rw,nosuid,nodev,noexec,relatime,seclabel) procon/proctypeproc(rw,relatime) devtmpfson/devtypedevtmpfs(rw,seclabel,size=494380k,nr_inodes=123595,mode=755) securityfson/sys/kernel/securitytypesecurityfs(rw,relatime) tmpfson/dev/shmtypetmpfs(rw,seclabel) devptson/dev/ptstypedevpts(rw,gid=5,mode=620,ptmxmode=000) tmpfson/runtypetmpfs(rw,mode=755) tmpfson/sys/fs/cgrouptypetmpfs(ro,mode=755) cgroupon/sys/fs/cgroup/systemdtypecgroup(rw,xattr,release_agent=/usr/lib/systemd/systemd-cgroups-agent,name=systemd) pstoreon/sys/fs/pstoretypepstore(rw,relatime) cgroupon/sys/fs/cgroup/freezertypecgroup(rw,freezer) cgroupon/sys/fs/cgroup/cpu,cpuaccttypecgroup(rw,cpuacct,cpu) cgroupon/sys/fs/cgroup/pidstypecgroup(rw,pids) cgroupon/sys/fs/cgroup/cpusettypecgroup(rw,cpuset) cgroupon/sys/fs/cgroup/net_cls,net_priotypecgroup(rw,net_prio,net_cls) cgroupon/sys/fs/cgroup/memorytypecgroup(rw,memory) cgroupon/sys/fs/cgroup/perf_eventtypecgroup(rw,perf_event) cgroupon/sys/fs/cgroup/devicestypecgroup(rw,devices) cgroupon/sys/fs/cgroup/hugetlbtypecgroup(rw,hugetlb) cgroupon/sys/fs/cgroup/blkiotypecgroup(rw,blkio) configfson/sys/kernel/configtypeconfigfs(rw,relatime) /dev/sda3on/typexfs(rw,attr2,inode64,noquota) selinuxfson/sys/fs/selinuxtypeselinuxfs(rw,relatime) systemd-1on/proc/sys/fs/binfmt_misctypeautofs(rw,fd=26,pgrp=1,timeout=300,minproto=5,maxproto=5,direct) debugfson/sys/kernel/debugtypedebugfs(rw,relatime) hugetlbfson/dev/hugepagestypehugetlbfs(rw,seclabel) mqueueon/dev/mqueuetypemqueue(rw,seclabel) /dev/sda1on/boottypexfs(rw,noquota) tmpfson/run/user/0typetmpfs(rw,size=100840k,mode=700)
一、磁盘格式化
| 命令 | 参数 | 涵义 |
mke2fs |
-t | 指定格式，不支持xfs； mkfs.ext4 = mke2fs -t ext4 |
| -b | 指定块大小 | |
| -m | 指定预留空间比（默认5%预留给超级用户） | |
| -i | 指定每组的inode数，默认4个块对应1个inode | |
| mkfs.xfs | 格式化成xfs |
测试示例：
[root@server02~]#mke2fs-txfs/dev/sdb2 mke2fs1.42.9(28-Dec-2013) Yourmke2fs.conffiledoesnotdefinethexfsfilesystemtype. Aborting... [root@server02~]#mkfs.xfs/dev/sdb2 Meta-data=/dev/sdb2isize=512agcount=4,agsize=131072blks =sectsz=512attr=2,projid32bit=1 =crc=1finobt=0,sparse=0 data=bsize=4096blocks=524288,imaxpct=25 =sunit=0swidth=0blks naming=version2bsize=4096ascii-ci=0ftype=1 log=internallogbsize=4096blocks=2560,version=2 =sectsz=512sunit=0blks,lazy-count=1 realtime=noneextsz=4096blocks=0,rtextents=0 [root@server02~]#blkid/dev/sdb2 /dev/sdb2:UUID="d1873a00-ba11-4635-81af-a1e9bd697f70"TYPE="xfs"
二、磁盘挂载
只有格式化的分区才能被挂载。挂载使用mount命令，卸载使用umount命令。使用“-o”可以跟各种选项。默认选项为rw,suid,dev,exec,auto,nouser,和async。
[root@server02~]#mount/dev/sdb2/mnt/ [root@server02~]#mount/dev/sdb3/mnt/ mount:/dev/sdb3写保护，将以只读方式挂载 mount:未知的文件系统类型“(null)” [root@server02~]#df-h 文件系统容量已用可用已用%挂载点 /dev/sda328G1016M27G4%/ devtmpfs483M0483M0%/dev tmpfs493M0493M0%/dev/shm tmpfs493M6.8M486M2%/run tmpfs493M0493M0%/sys/fs/cgroup /dev/sda1197M109M88M56%/boot tmpfs99M099M0%/run/user/0 /dev/sdb22.0G33M2.0G2%/mnt [root@server02~]#umount/dev/sdb2 [root@server02~]#df-h 文件系统容量已用可用已用%挂载点 /dev/sda328G1016M27G4%/ devtmpfs483M0483M0%/dev tmpfs493M0493M0%/dev/shm tmpfs493M6.8M486M2%/run tmpfs493M0493M0%/sys/fs/cgroup /dev/sda1197M109M88M56%/boot tmpfs99M099M0%/run/user/0
通过mount命令挂载的分区只在当前有效，当系统重启之后，分区将会消失。将分区挂载卸载/etc/fstab文件中，可以使系统启动时默认挂载。可以使用mount -a命令自动加载配置文件里的配置。
[root@server02~]#cat/etc/fstab # #/etc/fstab #CreatedbyanacondaonSatMay2706:10:332017 # #Accessiblefilesystems,byreference,aremaintainedunder'/dev/disk' #Seemanpagesfstab(5),findfs(8),mount(8)and/orblkid(8)formoreinfo # UUID=de480d95-018b-4e0b-a874-083a13d8412d/xfsdefaults00 UUID=82044aec-23c6-4e7f-8f05-51a24c0c956a/bootxfsdefaults00 UUID=be771427-d6c1-4d01-a8ab-a473e8df8ac5swapswapdefaults00 [root@server02~]#manfstab ...... DESCRIPTION ThefilefstabcontainsdescriptiveinformationaboutthevarIoUsfilesystems.fstabisonlyreadbyprograms,andnotwritten;itisthedutyofthesystemadministratortoproperlycreateandmaintainthisfile.Eachfilesystemisdescribedonaseparateline;fieldsoneachlineareseparatedbytabsorspaces.Linesstartingwith'#'arecomments,blanklinesareignored.Theorderofrecordsinfstabisimportantbecausefsck(8),mount(8),andumount(8)sequentiallyiteratethroughfstabdoingtheirthing. Thefirstfield(fs_spec).//UUID或LABEL Thisfielddescribestheblockspecialdeviceorremotefilesystemtobemounted. ...... Thesecondfield(fs_file).//挂载点 Thisfielddescribesthemountpointforthefilesystem.Forswappartitions,thisfieldshouldbespecifiedas`none'.Ifthenameofthemountpointcontainsspacesthesecanbeescapedas`\040'. ...... Thethirdfield(fs_vfstype).//分区格式 Thisfielddescribesthetypeofthefilesystem.Linuxsupportslotsoffilesystemtypes,suchasadfs,affs,autofs,coda,coherent,cramfs,devpts,efs,ext2,ext3,hfs,hpfs,iso9660,jfs,minix,msdos,ncpfs,nfs,ntfs,proc,qnx4,reiserfs,romfs,smbfs,sysv,tmpfs,udf,ufs,umsdos,vfat,xenix,xfs,andpossiblyothers.Formoredetails,seemount(8). ...... Thefourthfield(fs_mntops).//可选选项 Thisfielddescribesthemountoptionsassociatedwiththefilesystem. ...... Thefifthfield(fs_freq).//是否备份 Thisfieldisusedforthesefilesystemsbythedump(8)commandtodeterminewhichfilesystemsneedtobedumped.Ifthefifthfieldisnotpresent,avalueofzeroisreturnedanddumpwillassumethatthefilesystemdoesnotneedtobedumped. ...... Thesixthfield(fs_passno).//是否开机检测，不检查为0，检查为2 Thisfieldisusedbythefsck(8)programtodeterminetheorderinwhichfilesystemchecksaredoneatreboottime.Therootfilesystemshouldbespecifiedwithafs_passnoof1,andotherfilesystemsshouldhaveafs_passnoof2.Filesystemswithinadrivewillbecheckedsequentially,butfilesystemsondifferentdriveswillbecheckedatthesametimetoutilizeparallelismavailableinthehardware.Ifthesixthfieldisnotpresentorzero,avalueofzeroisreturnedandfsckwillassumethatthefilesystemdoesnotneedtobechecked.
