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Re: Filesystem recommendations

On Monday 26 April 2010 16:34:38 Boyd Stephen Smith Jr. wrote:
> On Monday 26 April 2010 16:05:31 B. Alexander wrote:
> > On Mon, Apr 26, 2010 at 2:22 PM, Boyd Stephen Smith Jr. <
> >
> > bss@iguanasuicide.net> wrote:
> > > I'm also a current reiser3 user.  I find the ability to shrink the
> > > filesystem
> > > to be something I am not willing to do without.
> >
> > You know, I said the same thing, but then as the kernel and GRUB and the
> > like advanced, I noticed that my reiserfs partitions would have to replay
> > the journal every time I rebooted, even after a clean shutdown. I started
> > calculating how many times I shrunk any of my partitions in the last 8
> > years, and I can only recall twice. And since I have several terabytes
> > around the house, I figure I can migrate data and delete/recreate
> >  partitions if I really need to reduce it.
> That doesn't seem right.  I have been using reiser3 since 2005, and my
>  system does not require a journal replay if I do a clean shutdown/reboot. 
>  A forced reboot through Alt+SysRq+B does trigger a journal replay (as it
>  should).
> I also have 4+ tebibytes but most of them are allocated to filesystems. 
>  I've had to shrink filesystems dozens of times since 2005, during or after
>  a data move.
> I don't use partitions (much), having been using LVM happily for everything
> except /boot.  I'm hoping to be able to move that onto LVM once I move to
> GRUB2 and GPT.
> > > I have not read the rest of the thread, but my off-the-cuff
> > > recommendation would be to start migration to btrfs.  Now that the
> > > on-disk format has stabilized, I am going to start testing it for
> > > filesystems other than /usr/local, /var, and /home.  Assuming I can
> > > keep those running well for 6-12
> > > months, I will migrate /usr/local, /var, and then /home, in that order,
> > > with a
> > > 1-3 month gap in between migrations.
> >
> > I might play with it for some non-critical partitions, or ones that I can
> > mirror on an established filesystem, even if it is only to use in an
> > "Archive Island" scenario, where I have a LV that I can mount, sync and
> > umount. However, btrfs is not included in the kernel, is it? As I recall,
> > nilfs2 has kernel support, but that was the only one of the new
> >  filesystems, at the time when I started looking at this.
> btrfs is included in in openSUSE 11.2.  It is also
> included in linux-image-2.6-686 and linux-image-2.6-amd64 for
>  lenny-backports, testing, and sid.  I don't normally deal with other
> architectures/distributions, so it might also be available there.
> > > I've already encountered an issue related to btrfs in my very isolated
> > > deployments.  The initramfs created by update-initramfs does not appear
> > > to mount it properly.  Instead I am given an '(initramfs)' prompt and I
> > > have to
> > > mount the filesystem manually (a simple two-argument mount command
> > > suffices)
> > > and continue the boot process.
> >
> > That is enough to give me pause...
> It doesn't appear to be a file system issue, but rather a problem with the
> initramfs scripts.  It could also be rooted in my configuration.  I know
>  that my "root=" kernel parameter has to differ from the device name in my
>  /etc/fstab in order to get the initramfs to correctly initialize LVM.

I wanted to report that I was able to diagnose and solve this.  The problem 
was that /lib/udev/vol_id in my initramfs could not identify a btrfs file 
system, which caused the scripts to try and mount the root file system using 
'-t unknown' as part of the command-line arguments.

I upgraded initramfs-tools and udev to the Sid versions.  This should cause a 
initramfs rebuild as part of the postinst, but if it doesn't do so on your 
system, be sure to run (update-initramfs -k all -u).  Now my system boots 
unattended with a btrfs '/'.

So, at this time, btrfs can be used for non-'/' file systems with the tools 
from lenny-backports.  However, newer udev/initramfs-tools are required to 
boot with a btrfs '/'.  I hope they are included in the Squeeze release.  I 
have not, and probably will not test a btrfs '/boot'.

I have also been encountering issues with suspend and resume on this new 
install.  I don't currently believe these are btrfs-related, either, but fair 
Boyd Stephen Smith Jr.           	 ,= ,-_-. =.
bss@iguanasuicide.net            	((_/)o o(\_))
ICQ: 514984 YM/AIM: DaTwinkDaddy 	 `-'(. .)`-'
http://iguanasuicide.net/        	     \_/

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