Hodne jsem Googloval okolo filesystemu a mam s tim i zkusenosti.
Co rikate tomuhle? :
www.webservertalk.com/archive99-2006-4-1481105.html :
> ... ... ... IMO, "journaling" provides *no* advantage, and some significant
disadvantages for small file systems. For small discs (like
a few 100 GB or so) a full fsck takes very little time anyway, and is
much better than using a journal. Journaling is sometimes touted
as being "atomic action" resulting in an "incorruptible" file
system. This is just UNTRUE, and the journal, if corrupt, can
result in PERMANENT DAMAGE when used. For large file systems,
there can be a significant advantage in speed of recovery from
power fail. This may justify the lesser confidence that using
the journal rather than fsck introduces. ... ... ...
... ... ... ...
> This is not my experience. My experience is that ext2 and ext3 are
similar in corruption, but ext3 HIDES that fact. It comes up fast
and "clean", but sometimes CORRUPT. I've never seen ext2 come up
corrupt after fsck. I've seen ext3 be declared "clean" by the
journal recovery, but be corrupt in a way that fsck could no longer
handle.
> The issue I have is that ext2, when corrupted, is often repairable,
and when it is not you can know that, and often recover information.
OTOH, ext3 when it is corrupted and not repairable by the journal may
*think* that it is and try to repair using the journal, after which,
although it may be declared "clean", it is not even recoverable, let
alone repairable, by fsck or the journal.
> IMO, doing a "repair" which clobbers the file system completely is
worse than not doing a repair and reporting a fatal error.
... ... ...
---
> ... fsck would not run against an ext3 file system no matter what I did.
... ... ... ...
Jde zde krome jineho o to, ze
NELZE SPOJOVAT WRITE CACHE harddisku a JOURNAL !
Kdy si ale koupite novy disk muze a asi i realne bude mit
jako default zapnutou write cache.
A kdo z laiku vi jak to vypnout?!
Prave ted se mi to stalo pri nakupu novych Hitachi 2.5" HDD.
Maji proste jako default zapnutou write cache.
Dle mych zkusenosti prave prime vytrzeni PC ze zasuvky s EXT3
vede velmi rychle po nekolika pokusech k VAZNYM PROBLEMUM s fsck
a s celym filesystemem!
fsck klidne nahlasi neco jako:
"Cannot repair filesystem, run fsck manually without -a -p ... parameters ..."
coz cloveka neprimo odsuzuje k nekolikahodinovemu studiu
"man fsck & spol."
Kdo si lajsne spustit jen tak fsck bez znalosti jak to funguje?!
Myslim ale, ze zhruba to same se mi stavalo i na EXT2.
Uz jsem s experimenty prestal, takze si to uz presne nepamatuji.
Jako maly zaver mi vyplynulo:
Leta pouzivam FAT16, na nem normalne neprijdete o data.
Mel jsem tisice padu systemu a vse OK.
Na vsech techto "modernich" filesystemech EXT2/3, JFS, XFS, ReisserFS,...
MUZETE REALNE PRIJIT o DATA! Spousta lidi o tom pise na WWW sve narky.
Takze pozor na tyhle novejsi filesystemy!
Stavalo se mi, ze byly nejak dotcene i soubory,
ktere jsem uz dlouho nebo vubec nikdy nepouzil.
Takze ted take zatim nevim co realne pouzit.
Téma: Filesystem (Přečteno 10470 krát)
