Tm hiu h thng file v h thng th mc chun ca Linux

Tm hiu h thng file vh thng th mc chunca LinuxNhm 6 Lp LTCNTT04-01 i hc i NamCu trc slide

H thng file v th mc chun trn Linux ngha cc th mc chun ca LinuxPhn 1Phn 21T chc cc tp tin trn Linux/ Root

- Mi mt file v th mc iu bt u t root directory- Ch c user root c quyn trn cc th mc cp bn di- Cn /root l home directory ca user root2. /bin User Binaries

- Cha file thc thi dng binary- Cc lnh s dng thng thng trong linux c s dng single-user mode c t di cu trc th mc ny- Cc cu lnh c s dng bi tt c cc user trong h thng s c t trong y. V d mt s lnh nh ps, ls, ping, grep, cp

1T chc cc tp tin trn Linux3. /sbin System Binaries

- Ging nh /bin, bn trong /sbin cng cha ng cc file thc thi dng binary. Cc lnh bn trong /sbin thng c s dng bi system administrator v dng cho cc mc ch l duy tr qun tr h thng.- Mt s lnh trong y v d nh iptables, reboot, ifconfig...4. /etc Configuration Files

- Thng thng /etc s cha file cu hnh cho cc chng trnh hot ng- /etc cng thng cha cc scripts dng start, stop, kim tra status cho cc chng trnh.- V d: /etc/resolv.conf (cu hnh dns-server ), hay /etc/network dng qun l dch v network

1T chc cc tp tin trn Linux5. /dev Device Files

- Cha cc file device i din cc hardware- V d: /dev/tty1 hay /dev/sda

6. /proc Process Information

- Cha ng thng tin v qu trnh x l ca h thng- y l mt pseudo filesystem cha ng cc thng tin v cc process ang chy- y l mt virtual filesystem cha ng cc thng tin ti nguyn h thng. V d: /proc/cpuinfo cung cp cho ta thng s k thut ca CPU

1T chc cc tp tin trn Linux7. /var Variable Files

- Cha ng cc file c s thay i trong qu trnh hot ng ca h iu hnh- V d system log s c t ti v tr ny+ System log file /var/log+ database file /var/lib+ email /var/mail+ Cc print queue /var/spool+ lock file /var/lock+ Cc file tm thi cn cho qu trnh reboot /var/tmp

8. /tmp Temporary Files

- Th mc ny cha cc file c to ra bi h thng v user- Cc file bn di th mc ny c xa i khi h thng reboot

1T chc cc tp tin trn Linux9. /usr User Programs

- Cha cc file binary, library, ti liu, source-code cho cc chng trnh.- /usr/bin cha file binary cho cc chng trnh ca user. - /usr/sbin cha cc file binary cho system administrator. Nu nh ta khng tm thy cc file system binary bn di /sbin th ta c th tm trong /usr/sbin. V d mt s lnh nh cron, sshd, useradd, userdel.- /usr/lib cha cc file libraries cho /usr/bin v /usr/sbin.- /usr/local dng cha chng trnh ca cc user, cc chng trnh ny c ci t t source. V d khi ta install apache t source th n s nm v tr l /usr/local/apache2

1T chc cc tp tin trn Linux10. /home Home Directories

- Home directory c cha ng thng tin c nhn ca cc user- V d /home/athena , /home/student11. /boot Boot Loader Files

- Cha ng boot loader v cc file cn cho qu trnh boot ty theo cc phin bn ca kernel- Cc file Kernel initrd, vmlinux, grub c t bn di /boot- V d initrd.img-2.6.32-24-generic, vmlinuz-2.6.32-24-generic

1T chc cc tp tin trn Linux12. /lib System Libraries

- Cha cc file library h tr cho cc file thc binary nm bn di /bin v /sbin- Tn ca cc file library thng l ld* or lib*.so.* . V d nh ld-2.11.1.so, libncurses.so.5.713. /opt Optional add-on Applications

- opt i din cho optional- Cha ng cc chng trnh thm vo ca cc hng khc

1T chc cc tp tin trn Linux14. /mnt Mount Directory

- Cha cc th mc dng system admin thc hin qu trnh mount

15. /media Removable Media Devices

- Cha th mc dng mount cho cc thit b removable. V d nh CDROM, Floppy...

16. /srv Service Data

- srv i din cho service- Cha ng cc dch v cho server, n lin quan n d liu. V d /srv/cvs cha ng CVS

2 ngha cc th mc chun trong LinuxH thng file EXTGii thiu:

- Ext Extended file system: l nh dng file h thng u tin c thit k dnh ring cho Linux. C tng cng 4 phin bn v mi phin bn li c 1 tnh nng ni bt. Phin bn u tin ca Ext l phn nng cp t file h thng Minix c s dng ti thi im , nhng li khng p ng c nhiu tnh nng ph bin ngy nay. V ti thi im ny, chng ta khng nn s dng Ext v c nhiu hn ch, khng cn c h tr trn nhiu distribution.

2 ngha cc th mc chun trong LinuxH thng file EXT2Gii thiu:

- Ext2 hay h thng tp tin m rng th hai l mt h thng tp tin dnh cho cc h thng nhn Linux. Lc u n c thit k thay th cho h thng tp tin m rng. N nhanh dng lm tiu chun cng nng ca cc loi h iu hnh Linux. Hn ch chnh ca n l khng phi h thng tp tin nht k.H thng file ext2 c gii thiu vo u nm 1993 v c thit k ring cho Linux. N c nhiu tnh nng tng cng khc phc cc hn ch ca cc h thng file khc.

2 ngha cc th mc chun trong LinuxH thng file EXT2Gii thiu:

Tnh nngMinixEXTEXT 2Kch thc h thng file ln nht64MB2GB4TBKch thc file ln nht64MB2GB2GBChiu di tn file ti a30 k t255 k t255 k tKch thc block ty binKhngKhngC2 ngha cc th mc chun trong LinuxH thng file EXT2Nhng c trng:

H thng tp tin Ext2 h tr cc kiu tp tin Unix chun.H thng tp tin Ext2 c kh nng qun l cc h thng tp tin trn nhng phn vng kch c rt ln.H thng tp tin Ext2 cung cp tn tp tin di. y l kh nng ca Linux m trn cc h thng UNIX chun khng h cung cp.H thng tp tin Ext2 d tr mt vi block cho super user (root). H thng tp tin Ext2 cho php truy xut n cc h thng khc nh FAT, FAT32, MSDOS trn Windows 9.x v DOS mt cch d dng.2 ngha cc th mc chun trong LinuxH thng file EXT3Gii thiu:

- c xy dng da trn c s ca h thng file Ext2 nhng Ext3 c thm vo mt tnh nng mi rt quan trng gip chng ta thao tc d liu c an ton hn, l journaling file system.2 ngha cc th mc chun trong LinuxH thng file EXT3Journaling l g?:

- Journaling ch c s dng khi ghi d liu ln cng v ng vai tr nh nhng chic c l ghi thng tin vo phn vng. ng thi, n cng khc phc vn xy ra khi cng gp li trong qu trnh ny, nu khng c journal th h iu hnh s khng th bit c file d liu c c ghi y ti cng hay cha.- Chng ta c th hiu nm na nh sau: trc tin file s c ghi vo journal, y vo bn trong lp qun l d liu, sau journal s ghi file vo phn vng cng khi sn sng. V khi thnh cng, file s c xa b khi journal, y ngc ra bn ngoi v qu trnh hon tt. Nu xy ra li trong khi thc hin th file h thng c th kim tra li journal v tt c cc thao tc cha c hon tt, ng thi ghi nh li ng v tr xy ra li .2 ngha cc th mc chun trong LinuxH thng file EXT3Chi tit:

- Ext3 v cn bn ch l Ext2 i km vi journaling. Mc ch chnh ca Ext3 l tng thch ngc vi Ext2, v do vy nhng a, phn vng c th d dng c chuyn i gia 2 ch m khng cn phi format nh trc kia. Tuy nhin, vn vn cn tn ti y l nhng gii hn ca Ext2 vn cn nguyn trong Ext3, v u im ca Ext3 l hot ng nhanh, n nh hn rt nhiu. Khng thc s ph hp lm file h thng dnh cho my ch bi v khng h tr tnh nng to disk snapshot v file c khi phc s rt kh xa b sau ny.2 ngha cc th mc chun trong LinuxH thng file EXT4Gii thiu:

- Ext4 cng ging nh Ext3, lu gi c nhng u im v tnh tng thch ngc vi phin bn trc . Nh vy, chng ta c th d dng kt hp cc phn vng nh dng Ext2, Ext3 v Ext4 trong cng 1 a trong Ubuntu tng hiu sut hot ng. Trn thc t, Ext4 c th gim bt hin tng phn mnh d liu trong cng, h tr cc file v phn vng c dung lng ln... Thch hp vi SSD so vi Ext3, tc hot ng nhanh hn so vi 2 phin bn Ext trc , cng kh ph hp hot ng trn server, nhng li khng bng Ext3.2 ngha cc th mc chun trong LinuxH thng file ReiserFSGii thiu:

- ReiserFS: c th coi l 1 trong nhng bc tin ln nht ca file h thng Linux, ln u c cng b vo nm 2001 vi nhiu tnh nng mi m file h thng Ext kh c th t c. Nhng n nm 2004, ReiserFS c thay th bi Reiser4 vi nhiu ci tin hn na. Tuy nhin, qu trnh nghin cu, pht trin ca Reiser4 kh chm chp v vn khng h tr y h thng kernel ca Linux. t hiu sut hot ng rt cao i vi nhng file nh nh file log, ph hp vi database v server email.2 ngha cc th mc chun trong LinuxH thng file BtrFSGii thiu:

- BtrFS thng pht m l Butter hoc Better FS, hin ti vn ang trong giai on pht trin bi Oracle v c nhiu tnh nng ging vi ReiserFS. i din cho B-Tree File System, h tr tnh nng pool trn cng, to v lu tr snapshot, nn d liu mc cao, chng phn mnh d liu nhanh chng... c thit k ring bit dnh cho cc doanh nghip c quy m ln.Mc d BtrFS khng hot ng n nh trn 1 s nn tng distro nht nh, nhng cui cng th n vn l s thay th mc nh ca Ext4 v cung cp ch chuyn i nh dng nhanh chng t Ext3/4. Do vy, BtrFS rt ph hp hot ng vi server da vo hiu sut lm vic cao, kh nng to snapshot nhanh chng cng nh h tr nhiu tnh nng a dng khc.2 ngha cc th mc chun trong LinuxH thng file JFS v ZFSGii thiu:

JFS c IBM pht trin ln u tin nm 1990, sau chuyn sang Linux. im mnh rt d nhn thy ca JFS l tiu tn t ti nguyn h thng, t hiu sut hot ng tt vi nhiu file dung lng ln v nh khc nhau. Cc phn vng JFS c th thay i kch thc c nhng li khng th shrink nh ReiserFS v XFS, tuy nhin n li c tc kim tra a nhanh nht so vi cc phin bn Ext.ZFS hin ti vn ang trong giai on pht trin bi Oracle vi nhiu tnh nng tng t nh Btrfs v ReiserFS. Mi xut hin trong nhng nm gn y v c tin n rng Apple s dng n lm file h thng mc nh. V d cy th mc ca h thng file Ext2:

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