Posts Tagged ‘cause and solution’

Fix “tar: Error exit delayed from previous errors” and its cause and solution

Monday, August 18th, 2014


tar: Error exit delayed from previous errors

error is a very common error encountered when creating archives (or backing up server configurations / websites / sql binary data). The error is quite unexplanatory and whenever creating files verbose in order to see the files added to archve in "real time" with lets say:

tar -czvf /tmp/filename_backup_date-of-backup.tar.gz /home/websites /home/sql

its pretty hard to track on exactly which file is the backup producing the Error exit delayed from previous errors, this is especially the case whenever adding to archive directories containing millions of tiny few kilobyte sized files. Many novice on uncautious Linux admins , might simply ignore the warning if they're in a hurry / are having excessive work to be done as there will be .tar.gz backup produced and whenever uncompressed most of the files are there and the backup error would seem not of a big issue.

However as backuping files is vital stuff, especially when moving the files from a server to be decomissioned you have to be extra careful and make the backup properly, e.g. figure out the cause of the error, to do so log the full output of tar operations with tee command, like so:

tar -czvf /tmp/filename_backup_date-of-backup.tar.gz /home/websites/ /home/sql | tee /tmp/backup_tar_full_output.log

Then you will have to review the file and lookup for errors with less search string – / (slash) – look for "error" and "permission den" keywords and this should point you to what is causing the error. In cases when millions of files are to be archived, the log might grow really big and hard to process, therefore a much quicker way to understand what's happening is to only log and show in shell standard output last file error with > (shell redirect):

tar -czvf /tmp/filename_backup_date-of-backup.tar.gz /home/websites /home/sql > /tmp/backup_failure-cause.log


tar: Cannot open: Permission denied
tar: Removing leading `/' from member names

The error indicates clearly the cause of error is lack of Permissions to read the file tnsnames.ora.20080918 so solution is to either grant permissions to non-root user with (chmod / chown) cmds, in my case grant perms to user hipo with which tar is ran, or run again the website backup with superuser, I usually just run with root user to prevent tampering with original permissions, e.g. to solve the error, either:

$ su root
# tar -czvf /tmp/filename_backup_date-of-backup.tar.gz /home/websites /home/sql

Or even better if sudo is installed and user is added to /etc/sudoers file

$ sudo tar -czvf /tmp/filename_backup_date-of-backup.tar.gz /home/websites /home/sql

Though permission errors is the most often reason for:

tar: Error exit delayed from previous errors, you should keep in mind that in some cases the error might be caused due to failing RAID membered disk drive or single hdd failure on systems that are not in some RAID array


How to solve “[crit] [client] (13)Permission denied: /var/lib/ejabberd/.htaccess pcfg_openfile: unable to check htaccess file, ensure it is readable, referer:” – Error Cause and Solution

Thursday, January 5th, 2012

While configuring JWchat domain, I've come across around an error:

pcfg_openfile: unable to check htaccess file, ensure it is readable

The exact error I got in /var/log/apache2/error.log looked like so:

[crit] [client] (13)Permission denied: /var/lib/ejabberd/.htaccess pcfg_openfile: unable to check htaccess file, ensure it is readable, referer:

The error message suggested /var/lib/ejabberd/.htaccess – is missing or not readable, however after checking i've seen .htaccess existed as well as was readable:

debian:~# ls -al /var/lib/ejabberd/.htaccess
-rw-r--r-- 1 www-data www-data 114 2012-01-05 07:44 /var/lib/ejabberd/.htaccess

At first glimpse it seems like the message is misleading and not true, however when I switched to www-data user (the user with which Apache runs on Debian), I've figured out the error meaning of unreadability is exactly correct:

www-data@debian:$ ls -al /var/lib/ejabberd/.htaccess
ls: cannot access /var/lib/ejabberd/.htaccess: Permission denied

This permission denied was quite strange, especially when considering the .htaccess is readable for all users:

debian:~# ls -al /var/lib/ejabberd/.htaccess
-rw-r--r-- 1 www-data www-data 114 2012-01-05 07:44 /var/lib/ejabberd/.htaccess

After a thorough look on what might go wrong, thanksfully I've figured it out. The all issues were caused by wrong permissions of /var/lib/ejabberd/.htaccess .You can see below the executable flag for all users (including apache's www-data) is missing :

debian:/var/lib# ls -ld /var/lib/ejabberd/drw-r--r-- 3 ejabberd ejabberd 4096 2012-01-05 07:45 /var/lib/ejabberd/

Solving the error, hence is as easy as adding +x flag to /var/lib/ejabberd :

debian:/var/lib# chmod +x /var/lib/ejabberd

Another way to fix the error is to chmod to 755 to the directory which holds .htaccess:

From now onwards pcfg_openfile: unable to check htaccess file, ensure it is readable err is no more 😉

Cause and solution for Qmail sent error “Requested action aborted: error in processing Server replied: 451 qq temporary problem (#4.3.0)”

Friday, October 28th, 2011

One of the qmail servers I manage today has started returning strange errors in Squirrel webmail and via POP3/IMAP connections with Thunderbird.

What was rather strange is if the email doesn’t contain a link to a webpage or and attachment, e.g. mail consists of just plain text the mail was sent properly, if not however it failed to sent with an error message of:

Requested action aborted: error in processing Server replied: 451 qq temporary problem (#4.3.0)

After looking up in the logs and some quick search in Google, I come across some online threads reporting that the whole issues are caused by malfunction of the (script checking mail for viruses).

After a close examination on what is happening I found out /usr/sbin/clamd was not running at all?!
Then I remembered a bit earlier I applied some updates on the server with apt-get update && apt-get upgrade , some of the packages which were updated were exactly clamav-daemon and clamav-freshclam .
Hence, the reason for the error:

451 qq temporary problem (#4.3.0)

was pretty obvious which is using the clamd daemon to check incoming and outgoing mail for viruses failed to respond, so any mail which contained any content which needed to go through clamd for a check and returned back to did not make it and therefore qmail returned the weird error message.
Apparently for some reason apparently the earlier update of clamav-daemon failed to properly restart, the init script /etc/init.d/clamav-daemon .

Following fix was very simple all I had to do is launch clamav-daemon again:

linux:~# /etc/inid.d/clamav-daemon restart

Afterwards the error is gone and all mails worked just fine 😉

swap_pager_getswapspace: failed, MySQL troubles on FreeBSD 7.2 cause and solution

Tuesday, May 3rd, 2011

Every now and then my FreeBSD router dmesg ( /var/log/ ) logs, gets filled with error messages like:

pid 86369 (httpd), uid 80, was killed: out of swap space
swap_pager_getswapspace(14): failed
swap_pager_getswapspace(16): failed
swap_pager_getswapspace(11): failed
swap_pager_getswapspace(12): failed
swap_pager_getswapspace(16): failed
swap_pager_getswapspace(16): failed
swap_pager_getswapspace(16): failed
swap_pager_getswapspace(16): failed
swap_pager_getswapspace(14): failed
swap_pager_getswapspace(16): failed
swap_pager_getswapspace(8): failed

Using swapinfo during the swap_pager_getswapspace(16): failed messages were logged in, I figured out that definitely the swap memory over-use is the bottleneck for the troubles, to find this I used the command:

freebsd# swapinfo
Device 1K-blocks Used Avail Capacity Type
/dev/ad0s1b 49712 45920 3792 92% Interleaved

After some investigation, I’ve figured out that the MySQL server is causing the kernel exceeded swap troubles.

My current MySQL server version is installed from the ports tree, whether I’m using the bsd port /usr/ports/databases/mysql51-server/ and it appears to work just fine.

However I have noticed that the mysql-server is missing a my.cnf file!, which means the mysql server is running under a mode with some kind of default configurations.

Strangely in the system process list it appeared it is using a default my.cnf file located in /var/db/mysql/my.cnf

Below you see the paste from the ps command:

ps axuww freebsd# ps axuww | grep -i my.cnf | grep -v grep
mysql 7557 0.0 0.1 3464 1268 p1 I 12:03PM 0:00.01 /bin/sh /usr/local/bin/mysqld_safe --defaults-extra-file=/var/db/mysql/my.cnf --user=mysql --datadir=/var/db/mysql --pid-file=/var/db/mysql/pcfreak.pidmysql 7589 0.0 5.1 93284 52852 p1 I 12:03PM 0:59.01 /usr/local/libexec/mysqld --defaults-extra-file=/var/db/mysql/my.cnf --basedir=/usr/local --datadir=/var/db/mysql --user=mysql --pid-file=/var/db/mysql/ --port=3306 --socket=/tmp/mysql.sock

Nevertheless it appeared the sql server is running the file /var/db/mysql/my.cnf conf was not existing! This was really weird for me as I’m used to have the default my.cnf from my previous experience with Linux servers!

Thus the next logical thing I did was to create my.cnf conf file in order to be able to have a proper limiting configuration for the sql server.

The FreeBSD my.cnf skele files are found in /usr/local/share/mysql/, here are the 4 files one can use as a starting basis for further configuration of the mysql-server.

freebsd# ls -al /usr/local/share/mysql/my-*.cnf
-r--r--r-- 1 root wheel 4948 Aug 12 2009 /usr/local/share/mysql/my-huge.cnf
-r--r--r-- 1 root wheel 20949 Aug 12 2009 /usr/local/share/mysql/my-innodb-heavy-4G.cnf
-r--r--r-- 1 root wheel 4924 Aug 12 2009 /usr/local/share/mysql/my-large.cnf
-r--r--r-- 1 root wheel 4931 Aug 12 2009 /usr/local/share/mysql/my-medium.cnf
-r--r--r-- 1 root wheel 2502 Aug 12 2009 /usr/local/share/mysql/my-small.cnf

I have chosen to use the my-medium.cnf as a skele to tune up, as my server is not high iron one e.g. the host I run the mysql is a (simple dual core 1.2Ghz system).

Further on I copied the /usr/local/share/mysql/my-medium.cnf to /var/db/mysql/my.cnf e.g.:

freebsd# cp -rpf /usr/local/share/mysql/my-medium.cnf /var/db/mysql/my.cnf

As a next step to properly tune up the default values of the newly copied my.cnf to my specific server I used the Tuning-Primer MySQL tuning script

Using is really easy as all I did is download, launch it and follow the script suggestions to correct some of the values already in my.cnf

I have finally ended up with the following my.cnf after using to optimize mysql server to work with my bsd host

Now I really hope the shitty swap_pager_getswapspace: failed errors would not haunt me once again by crashing my server and causing mem overheads.

Still I wonder why the port developer Alex Dupre – choose not to provide the default mysql51-server conf with some kind of my.cnf file? I hope he had a good reason.