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<div class="moz-cite-prefix">On 2016-04-22 10:45 PM, Alan W. Irwin
wrote:<br>
</div>
<blockquote
cite="mid:alpine.DEB.2.11.1604222218290.698@enira.zlyna.ubzr"
type="cite">On 2016-04-22 19:56-0700 Murray Strome wrote:
<br>
<br>
<blockquote type="cite">When I reboot into Ubuntu (16.04) on at
least one computer, first it will not boot. If I chose Advanced
Options, and Upstart I get a message saying something like
"Serious error in /usr", which is a separate partition.
<br>
<br>
I am given a few options, but if I chose "I" to ignore the
error, it does boot OK, and I have several options for Windows
managers. In the past, Icewm was often the best, but right now,
Plasma (i.e. KDE) seems to be working the best.
<br>
<br>
What I would like to know is:
<br>
How can I find out what the "serious errors" might be, and how
can I fix them? I really do not want to have to go through the
pain of reinstalling Ubuntu if I don't have to do so.
<br>
<br>
Any help would be greatly appreciated.
<br>
</blockquote>
<br>
Hi Murray:
<br>
<br>
One obvious possibility for a serious error is you have some
<br>
bad memory. To check memory, I suggest you install and use the
<br>
memtest86+ Ubuntu package (if you haven't installed that
<br>
already). That will create an extra grub option to run
<br>
that memory test every time you get concerned about system
<br>
integrity.
<br>
</blockquote>
<b>No errors reported by memtest (it takes several hours to check my
16G RAM)</b><br>
<blockquote
cite="mid:alpine.DEB.2.11.1604222218290.698@enira.zlyna.ubzr"
type="cite">
<br>
Assuming that test gives good results, then another possibility is
<br>
your disk is dying (i.e., ran out of spare blocks to replace the
bad
<br>
ones that modern disks self detect). To check for that
possibility, I
<br>
suggest you umount your /usr partition, then do a file system
check on
<br>
that unmounted partition to see if your file system is consistent
or
<br>
not.
<br>
<br>
</blockquote>
<b>fsck on that partition reports no errors, says file system is
clean</b><br>
<blockquote
cite="mid:alpine.DEB.2.11.1604222218290.698@enira.zlyna.ubzr"
type="cite">man fsck
<br>
<br>
Also, if you are using rsync for backups to an external disk, then
if
<br>
you have ever experimented by repeating the rsync command for a
<br>
filesystem you will find that second rsync to be extremely fast
and it
<br>
should show no changes for the second rsync assuming there have
been
<br>
no writes to the internal filesystem in the interval between the
two
<br>
rsync commands. In addition from time to time you might also want
to
<br>
try using the --checksum option (man rsync) for a third rsync
command.
<br>
That effectively runs a checksum on every file on the internal
<br>
filesystem and the external filesystem and updates the external
<br>
filesystem if there are any checksum differences. So it is quite
slow
<br>
compared to normal rsync operations, but it does constitute a
complete
<br>
end-to-end check that both internal disk and external disk have
<br>
identical files. So assuming your external disk is healthy, that
tests
<br>
that your internal disk is being read consistently without random
bit
<br>
flips between the particual rsync command that wrote each of the
<br>
external files and the last rsync command. So it is a fairly good
<br>
check that all is well with both the internal and external disks,
and
<br>
I have formed the habit of using this check (which typically takes
<br>
several hours) whenever there is any question concerning system
<br>
integrity.
<br>
</blockquote>
<b>I have not been using rsync for backups</b><br>
<blockquote
cite="mid:alpine.DEB.2.11.1604222218290.698@enira.zlyna.ubzr"
type="cite">
<br>
Alan
<br>
</blockquote>
<b>I have also run some of the things in the advanced options for
ubuntu, like the one to check for broken packages, etc. I still
get this message, however most things do seem to work OK after I
say to ignore the errors in /usr when booting in upstart. The only
thing that I noticed not to be working properly was Synaptic.
However, after the latest reboot (I had just finished running
memtest and fsck from a live DVD), it is working again.<br>
<br>
Murray<br>
</b>
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