:: Re: [DNG] vdev
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Author: Adam Borowski
Date:  
To: dng
Subject: Re: [DNG] vdev
On Sun, Aug 14, 2016 at 10:15:06AM +0800, Robert Storey wrote:
> =================
> > From: Adam Borowski <kilobyte@???>
> >
> > For anything that can break your system, and for running unstable, btrfs
> is
> > awesome. You can make snapshots at any point (most people have at least a
> > daily cronjob), and then restore or mount live when you want. And when
> you
> > make it unbootable, you append subvol=backups/@2016-08-12 (or whatever
> > you named it) in grub, and there you go.
>
> Wow, wish I'd read that before I installed my test Devuan. I used ext4. Any
> way to change that to btrfs without reinstalling?


Actually, ext[234]->btrfs is the only filesystem combination (not counting
ext* upgrades) I know about that can be converted in-place. However, I'm
not sure I would recommend this. The converter was pretty much orphaned for
a long time, bitrotting to the point of uselessness, until very recently.
It received a bunch of fixes but might still be risky.

If you have a full set of backups, you might try it:
https://btrfs.wiki.kernel.org/index.php/Manpage/btrfs-convert
https://btrfs.wiki.kernel.org/index.php/Conversion_from_Ext3

Note that the conversion can be undone, however, as long as the undo data
isn't deleted, btrfs has to step around any block that holds an ext4 inode
or directory, resulting in quite unoptimal operation.

> =================
>
> > > > On August 13, 2016 at 4:45 AM aitor_czr <aitor_czr@???>
> > > > wrote:
> > >
> > > As you know, today is August 12, not August 13.
> > >
> > > PLEASE FIX YOUR COMPUTER CLOCK!!!!
>
> Funny, after installing my test copy of Devuan, I started running into
> clock issues too. Turned out that I had my original Devuan set up to see
> the clock as UTC rather than local time, while my test Devuan had local
> time for both.
>
> For most users, life is simpler when the hardware clock is set to local
> time. Anyway, if you've got more than one distro installed, at least be
> consistent. So if you haven't discovered it already, check the file
> /etc/adjtime and if necessary, change "UTC" to "LOCAL".


You might get away with hardware clock in local time only if you have only
one installed system. If you have more than one (even of the same distro),
the systems have no way of knowing if another did or not adjust the time on
DST changes, thus every one of them will screw up the clock the first time
you boot them after a change. There's similar joy if you travel to a
different time zone. Having RTC in UTC has no such problems, and even
Windows can do that (although this requires an undocumented regedit
setting):

https://wiki.archlinux.org/index.php/time#UTC_in_Windows

--
An imaginary friend squared is a real enemy.