Gentoo Archives: gentoo-user

From: Michael Mol <mikemol@×××××.com>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] jbd2 keeps spinning my disk up
Date: Sun, 31 Jul 2011 21:31:11
In Reply to: Re: [gentoo-user] jbd2 keeps spinning my disk up by Peter Humphrey
1 On Sun, Jul 31, 2011 at 1:39 PM, Peter Humphrey
2 <peter@××××××××××××××.org> wrote:
3 > On Sunday 31 July 2011 17:05:39 Michael Mol wrote:
4 >
5 >> However, if it's doing that, then it probably has something it needs to
6 >> write to disk. That might be metadata updates.
7 >
8 > What, at least once a minute? While the system's idling, waiting for
9 > something to do? Doesn't sound likely to me.
10 >
11 >> Have you tried adding things to your mount parameters like 'noatime' or
12 >> 'relatime'?
13 >
14 > I've been specifying 'noatime' on all partitions for several years now; it's
15 > automatic behaviour on my part.
16 >
17 >> What about "data=writeback"?
18 >
19 > I don't like the sound of the warning in the man page.
20 >
21 > Thanks for the ideas. So far I'm inclining to the reformatting I mentioned.
23 Here's what I think is happening:
25 ext3/ext4 is not going to arbitrarily poll writes to disk without
26 there being something to write. Some program, somewhere on your system
27 is doing something that involves modifying a file. Any filesystem that
28 provides guarantees about disk integrity is going to get that data to
29 a physically persistent state ASAP. That's why we have journaled
30 filesystems in the first place: to speed that up.
32 So, with the same application and configuration set, you're going to
33 see the same behavior on any filesystem which provides such
34 guarantees.
36 You're perfectly welcome to reformat if you're so inclined; it really
37 sounds like you're simply more comfortable (or more interested in)
38 reiserfs. If you perceive that that solve your problem, great--but I
39 don't think that would really solve the underlying technical issue.
41 What you really want to do is find some way to log what's actually
42 driving the data writes. If it were a particular app, it'd be as
43 simple as launching the app via strace and analyzing the output. I
44 don't know how one would do that system-wide, though. Perhaps someone
45 else might have ideas.
47 --
48 :wq