Gentoo Archives: gentoo-user

From: Richard Fish <bigfish@××××××××××.org>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] file system problems - what is proper maintanence?
Date: Tue, 27 Jun 2006 01:20:20
In Reply to: [gentoo-user] file system problems - what is proper maintanence? by Mark Knecht
1 On 6/24/06, Mark Knecht <markknecht@×××××.com> wrote:
2 > That said, I seem to have file system problems on my external 1394
3 > hard drives. I do not know if this is due to a recent move to
4 > 2.6.17-rt1, or bad maintenance on my part, or just bad luck. I've
6 Well, I've had various problems with external drives. I have 3
7 1394/USB2 combo drives that I use for backups. If I connect them via
8 1394, they will start to have problems at some point during my
9 backups....sometimes several Gb will transfer fine, and then it will
10 hiccup with various read/write failures. I *never* have a problem
11 with these same drives connected via USB.
13 In another event, I moved a 2.5" drive from a slightly damaged USB2
14 case to a new one. The new case started corrupting data written to
15 it, without any warning or errors. Filesystem checks would always
16 report no errors, but for example I could transfer kernel sources to
17 the drive, but they would fail to extract from there. I eventually
18 replaced the case, (same drive) and that cleared up all problems, but
19 I had to restore the files from backups as they were actually
20 corrupted on write (vs just not being able to read them correctly).
22 So, what I really recommend you do for awhile is to do an md5sum of
23 any files that you transfer to the drive before transferring them.
24 And then periodically do a md5sum -c to verify the file contents.
25 That is really the best way to make sure your drives are working
26 right, and that your data hasn't been corrupted.
28 And if they are combo drives, try the USB2 connection instead.
30 > I wondered if there is really any value to a journaled file system?
31 > Did it protect me? I cannot tell.
33 With one exception, journaled filesystems are designed to protect
34 themselves, not your data. That is, if a crash occurs in the middle
35 of an operation, the filesystem meta-data will not be corrupted. It
36 will know how large all files should be, which blocks are allocated to
37 which files, whether any files should be deleted, and so on. It does
38 not guarantee the actual file data however. But this 'guarantee' is
39 useless if a hardware problem is corrupting the filesystem, which
40 appears to be the problem here.
42 The one exception is ext3 when mounted with the 'data=journal' option.
43 But this makes the filesystem fairly slow, and still doesn't help
44 with hardware problems....
46 -Richard
47 --
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