History source of Computer Problem-Solution (Open)(No. 10)

This is a page of "How to" solve some computer problems that may happen.

P = problem;
S = solution

#contents

** P: (2009.07.17) Load average of FLEX is very high. [#ba0d0fa4]
This is due to mounting problem again (mount NFS). After checking mount status, it is found that a network harddisk was not unmounted nicely before turning off.
*** S: Re-mount (turn on) the harddisk, and do some safety procedure. [#l1c8b137]
- check mount status:
 # mount
- umount once (assuming mount point is /mnt/backup):
 # umount -f /mnt/backup
- synchronize several times:
 # sync
 # sync
 # sync
- check df or mount status again
- if the harddisk has been nicely unmounted, then it is safe to turn it off.

** P: (2009.07.02 night, 9:30 PM) Flex problem again [#l21eccff]
I (Nugraha) could not login to flex webmail even using web browser: 
 ERROR: Could not complete request.
and I could not login either to flex work account (ssh).
*** S: ? [#i206d687]

** P: (2009.07.02) Flex is unstable for logining or e-mails. [#ac90f02f]
*** S: mount to tube:/home1-old was not allowed any more. [#e2a3634b]

 comment out one line in /etc/auto.misc 
 # home1    172.17.4.134:/home1-old

 ./S28autofs forcerestart

 I also delete in /etc/exports 

 the requests from 172.17.4.184 (nuguraha) 172.17.4.188 (mahabubu)
 and 172.17.4.127 (furu).

 exportfs -a

 we also need to restart nfs
 /etc/rc5.d/S60nfs restart

** P: (2009.06.03) Today we were failed to run ether-wake command on new-PXE server/client machines using new Hub/router. [#m53007b8]
*** S: We manually turn those on and off. After that ether-wake (wake-on-Lan) command was successful. [#a08cf22e]

** P: PEX (network boot) is now installing 2009.5.1 [#e8f71204]
*** S: finished. status [[PXE Server (Open)]] [#p74ace39]

** P: NIS (network information services) will be moved from tube to flex 2009.5.1 [#mb7aa695]
*** S: not yet finished. status [[Network Information System]] [#t46d19f5]

----
The following problems are solved.
----

** P: We move /etc/passwd then we can not be root. No more even shutdown. [#oaefbc51]
*** S: cntl-alt-del and reboot. Then when OS selection, push any arrow. [#v36584e8]
Then many selection of OS appears. Select one of OS, and press E.
Then select kernel and press E again. Then you can edit the command for starting  kernel and add "single" in the last of the command. Finally select "b" for booting and single user mode appears. Make /etc/passwd files and exit and runlevel 5 is recovers. 

Even if we used NIS, we should not delete /etc/passwd /etc/group and /etc/shadow.

** P: Flex was in a trouble today (2009.06.01). Problem was, we were failed to log-in to the flex. NIS is not running. Finally we solved it. See solution [#e62b9d19]
*** S: We found the graphics card is very unstable on Tube machine (172.17.4.134). May be accidentally we pull the card out and tube machine was failed to boot properly. As Flex uses NIS from Tube that is why we were unable to  log on to Flex. [#l1e69691]


** P: linux emacs ispell error (no language "eu") 2009.4.24 [#xf61128d]
*** S: solved. "M-x ispell-change-dictionary" and select english [#t33f8f93]
*** S: solved. Edit .emacs to add (setq ispell-dictionary "english") [#l1a50648]

** P: How to update the files of remote to the files of local [#lb59159d]
*** S: solved. "rsync -avc -e ssh saito@remote:/home/saito/book09/ /rsaito/book09"[#f25e1654]
History source of Computer Problem-Solution (Open) (No. 10)
