[CentOS] newbie question on installation over existing Linux

Tue Jun 9 16:26:47 UTC 2015
Valeri Galtsev <galtsev at kicp.uchicago.edu>

On Tue, June 9, 2015 10:51 am, Kay Schenk wrote:
> On 06/08/2015 06:29 PM, Peter wrote:
>> On 06/09/2015 12:19 PM, John R Pierce wrote:
>>> On 6/8/2015 5:08 PM, g wrote:
>>>> ie, partition for boot, partition for swap, partition for /,
>>>> home, partition for usr, partition for var, partition for home2,
partition for what ever.
>>> that model is not generally recommended anymore, at least not putting
/usr on its own partition, there's just too many issues with that
nowdays.   I don't like putting /var in its own partition either as
>>> all too intertwined with root.   the problem with lots of little
partitions is your freespace gets fragmented.
>>> /home in a dedicated partition, sure.
>>> /var/lib/${DATABASE_OR_WEB_SERVER}, ditto...
>> The real issue is that you cannot put /usr on a dedicated partition
anymore as of CentOS 7.  This is because /bin, /lib and /lib64 are
symbolic linked in the /usr equivalents now.  The (previous) purposes
>> having a separate /bin and /lib was so that programs and libs required
at boot time could be run before the rest of the fs was mounted up if
/usr were on a separate partition.  Now they've been consolidated and
symlinked so if you put /usr on a separate partition then the system
won't be able to access critical apps during boot.

This change looks awfully unprofessional to me...

>> You can thank Fedora for making that rather pointless change and
breaking that capability.
>> Peter
> Just curious what happens in this case. Do the apps wait and/or retry
until /usr is mounted or does the boot fail?

I for one still have /usr living on separate partition on CentOS 7
workstations which are few (do not and never will run servers under CentOS
7). And I have sixth field (fs_passno) 2 for /usr in /etc/fstab. Didn't
have problems with these boxes so far. Though fs_passno should probably be
changed to 1 (as for /) according to description of new layout (i.e. _all_
libraries and binaries now physically live in /usr).

Just my $0.02


Valeri Galtsev
Sr System Administrator
Department of Astronomy and Astrophysics
Kavli Institute for Cosmological Physics
University of Chicago
Phone: 773-702-4247