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Ka8ws hdh eipame, oi clients moirazontai oloklhro to root-fs me ton
server. Alla, fysika, oi clients mporoun mono na to diabasoyn : Aytos
einai o tropos leitoyrgias toy sygkekrimenoy systhmatos.
Dystyxws, ta pragmata den einai toso apla. Yparxoyn kanadyo problhmata,
poy prepei na jeperasoyme s' ayto to aplo sxhma.
Ka8e ws xreiazetai to (me dynatothta eggrafhs) diko toy antigrafo enos ari8mou apo katalogoys.
Sto synh8ismeno sthsimo, to Linux prepei na mporei na gracei stoys ejhs
katalogoys :
- /dev
- /var
- /tmp
Yparxoyn 3 luseis gi' ayto, apo tis opoies h mia 8a doylecei mono sto
/dev :
- fortwnoyme ena ramdisk kai to gemizoyme me untarring enos tarball,
h antigrafontas ena protypo (template) katalogo.
- Pleonekthmata :
- Ka8arizei me ka8e epanekkinhsh, h opoia sbhnei arxeia .tmp kai
arxeia logs. Den xreiazetai synthrhsh, anti8eta ap' o,ti oi katalogoi
sthn pleyra toy server.
- Den katalambanei xwro ston server, kai de dhmioyrgei kykloforia
sto diktyo. Ena ramdisk xrhsimopoiei ligoteroys poroys toy server kai toy
diktuoy, kai einai taxutero.
- Meionekthmata :
- Katalambanei mnhmh.
- Ta logs den diathrountai meta apo epanekkinhsh. Ean pragmatika
xreiazeste logging gia ola ta clients, peite sto syslog na epanakatey8unei
to logging pros ton server.
- dhmioyrgoume ena dir gia ka8e ws epanw ston server, kai to
fortwnoyme rw epanw sto nfs.
- Pleonekthmata & meionekthmata :
- Gia ta dirs toy server, ta parapanw pleonekthmata-meionekthmata
antistrefontai.
- Ston kernel 2.2, to devfs mporei na xrhsimopoih8ei anti toy /dev .
Ayto einai ena virtual filesystem, san to /proc toy /dev.
-
- Pleonekthmata :
- To devfs xreiazetai elaxisth mnhmh, moiazei me ramdisk /
ka8oloy xwro sklhrou diskoy epanw ston server, kai einai taxutato. Ena
synh8ismeno /dev xreiazetai toylaxiston 1.5 MB, afou to elaxisto mege8os
arxeioy (kai ara enos device) einai 1k, kai yparxoyn peripoy 1200 devices.
Fysika, mporeite na xrhsimopoihsete ena protypo "apogymnwmenoy" /dev, me
mono ta periexomena poy 8elete, gia na ejoikonomhsete kamposo xwro. To
1.5 MB einai polu gia ramdisk, kai epishs den einai wraio epanw ston
server.
- To devfs aytomata dhmioyrgei kataxwrhseis gia tis nees kai tis
anixneymenes syskeyes, synepws den xreiazetai synthrhsh.
- Meionekthmata :
- Xanetai ka8e allagh sto /dev , opws h dhmioyrgia symlinks gia to
pontiki kai to cd-rom. To devfs exei ena script, to rc.devfs, poy swzei
aytes tis allages. Ta scripts, poy sas dinw s' ayto edw to howto,
apoka8istoun aytomata tis ry8miseis twn symlinks, kalwntas to rc.devfs .
An kanete opoiesdhpote allages sto /dev , xreiazetai na kalesete eseis to
rc.devfs, gia na tis swsete, dinontas :
/etc/rc.d/rc.devfs save /etc/sysconfig
Opws blepete, yparxoyn kamposoi tropoi gia na ly8ei ayto to problhma.
Gia to ypoloipo meros aytou toy howto, kratame tis akoloy8es epiloges :
- Anti gia to /dev , 8a xrhsimopoioume to devfs.
- Anti gia ta /var kai /tmp , 8a xrhsimopoioume ena diamoirazomeno
(shared) ramdisk toy enos MB. (To kanoyme shared, gia na xrhsimopoihsoyme
ton xwro toy oso to dynaton apotelesmatikotera.) To /tmp antika8istatai m'
ena symlink pros to /var/tmp , gia na kanoyme efikto ton diamoirasmo.
- Doyleuei ej isoy kala to na gemisoyme to ramdisk me tarballs, h
protypa (template) dirs. Alla me ta protypa directories einai polu
eykolotero na kanoyme allages, ara 8a xrhsimopoihsoyme ayta.
Mporei n' anagkastoume na dwsoyme dikaiwma eggrafhs sto /home
Den einai pragmatiko problhma, afou se ka8e sthsimo client/server se
*nix systhmata to /home fortwnetai rw apo ton server. 'Ara, 8a kanoyme
akribws ayto! ;)
Pws briskei enas ws to ip toy, wste na epikoinwnhsei me ton server;
Eytyxws gia mas, ayto to problhma exei hdh ly8ei, kai o pyrhnas toy
Linux yposthrizei duo tropoys aytomatoy ka8orismou ths dieu8ynshs ip :
- RARP
- Bootp
To rarp einai eykolotero sth ru8mish, to bootp einai to pio eyelikto.
Mia poy oi perissoteres bootroms (ROMs ekkinhshs apo karta diktuoy)
yposthrizoyn mono to bootp, ayto kai 8a xrhsimopoihsoyme.
Ti ginetai me tis ry8miseis gia ka8e ws
Sto RedHat, ta perissotera arxeia ry8misewn poy ejartwntai apo ton
sygkekrimeno H/Y, briskontai hdh sto /etc/sysconfig . Emeis 8a
metakinhsoyme monaxa osa den briskontai ekei, kai 8a baloyme symlinks.
Meta, 8a fortwsoyme ena jexwristo /etc/sysconfig gia ka8e ws. Ki ayto
einai to mono meros twn ry8misewn, poy ejartatai apo th distribution :
Se alles distributions, mporeite apla na ftiajete ena directory ry8misewn,
na metakinhsete ola ta mh diamoirazomena arxeia ry8misewn ekei, kai na
dhmioyrghsete symlinks. Epishs, to /etc/rc.d/rc3.d (h ta paromoia twn
ypoloipwn distributions) mporei na xreiastei na diaforopoih8oun ston
server, ap' o,ti einai stoys workstations. Ypo8etontas oti oloi oi ws
trexoyne tis idies services sto runlevel 3, 8a ftiajoyme jexwrista
runlevels 3 gia toys workstations kai ton server :
- kataskeyh toy /etc/rc.d/rc3.ws kai toy /etc/rc.d/rc3.server
- kanoyme to /etc/rc.d/rc3.d symlink pros to /etc/sysconfig/rc3.d
- kanoyme to /etc/sysconfig/rc3.d symlink pros to katallhlo
/etc/rc.d/rc3.xxx
- antika8istoume to S99local sto rc3.ws m' ena link pros to
/etc/sysconfig/rc.local , wste ka8e ws na exei to diko toy rc.local
Diafora problhmata
Yparxoyn akomh kapoia problhmata :
- To /etc/rc.d/rc.sysinit xreiazetai to /var, ara to /var prepei na
fortw8ei h na dhmioyrgh8ei prin trejei to /etc/rc.d/rc.sysinit . Epishs,
kalo 8a htan to gia ka8e ws /etc/sysconfig na fortw8ei prin trejoyn
opoiadhpote initscripts.
- 8a dwsoyme ton kwdika gia ena script ekkinhshs gia ws, epanw-epanw
sto /etc/rc.d/rc.sysinit . Shmeiwste oti ayto to script 8a to trejei
(fysika) kai o server kata thn ekkinhsh, ara to script prepei na problecei
ayto to endexomeno, kai na mhn kanei tipote epanw ston server.
- Prepei na mporoume na gracoyme sto /etc/mtab :
- Ayto edw mporei na mas kanei kolpa! Apla ftiajte ena link pros to
/proc/mounts , kai epishs ftiajte ena adeio arxeio mounts sto /proc , wste
ta fsck kai mount na mhn parapone8oun oso trexoyn ta initscripts, otan to
/proc den exei fortw8ei akomh. Shmeiwsh : To smb(u)mount den sebetai to
na einai link to mtab, kai grafetai panw toy. Ara, an 8elete na
xrhsimopoihsete to smb(u)mount, ftiajte wrapper scripts, poy apoka8istoun
to symlink.
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