Bug#652275: Guided partitioning should not offer separate /usr, /var, and /tmp partitions; leave that to manual partitioning
On Sun, 18 Dec 2011, Josselin Mouette <joss@debian.org> wrote:
> > Doing this has many advantage. Like, if your laptop has to unexpectedly
> > reboot (like when you inadvertently removed power cord when batteries
> > were not plugged, which happens often in real life), having separated
> > partitions usually makes the fsck faster.
>
> This is complete bullshit. With a journaled filesystem, the boot time
> will greatly increase with the number of filesystems to check. If no
> files were modified in /usr, they won’t be mentioned in the journal, and
> that’s all. But having one journal to parse for all the system is
> definitely a measurable improvement.
If we want to improve fsck time then the best thing to do would be to consider
a different default value for the -i option of mke2fs.
The current default is to have one Inode per 16K of disk space. Of the
Maildir format mail servers that I run the one with the smallest disk space
used per Inode has 307G and 4773821 Inodes in use for an average of 67K per
Inode. A randomly selected Debian workstation with a lot of packages
installed has for it's root filesystem 9.1G and 191111 Inodes for an average
of 49K.
As it seems quite unlikely that any non-root filesystem is going to have a
smaller average Inode space usage than the root filesystem (I had expected
Maildir to be the pathological case of small files) it seems quite safe to
make the default be -i 49152 for non-root filesystems and be -i 32768 for root
filesystems.
Finally using ext4 features either through "mke2fs -t ext4" or "mke4fs" will
give you better fsck performance. Are we doing ext4 by default nowadays?
As an aside "mke2fs -t ext4" includes huge_file, dir_nlink, and extra_isize
while mke4fs doesn't. This difference seems wrong to me.
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