he1ix' blog

as usually, we took tons of pictures during our last vacation, so eventually the memory card (a SD card) ran out of space. luckily, I had another SD within reach, so we just swapped them and went on…
arriving at home, I started downloading the pictures. when I plugged in the second card, loads of error-messages appeared, indicating a badly broken FAT32 filesystem. none of the newly taken pictures was there Continue reading ‘recovering JPGs from a corrupted filesystem’ »

to restore a dump from a MySQL database created on a debianish Linux system, just feed the dumped SQL to the command-line mysql client like this:

mysql -u root -p < mysql-all-2010-03-28-0515.sql

since the whole content of all MySQL databases are overwritten with that stored in the dump, credentials are affected as well. that’s the reason why debian’s system tools won’t work any more after restoring the old dump, since debian creates a maintenance-user called “debian-sys-maint” during the installation and stores the randomly generated credentials in “/etc/mysql/debian.cnf” so it’s sufficient to just copy the “password” values from the old file into the new one and restart mysql. otherwise, you will run into an error like this:

/etc/mysql/debian-start[3181]: Running 'mysqlcheck'...
/etc/mysql/debian-start[3181]: /usr/bin/mysqlcheck: Got error: 1045: Access denied for user 'debian-sys-maint'@'localhost' (using password: YES) when trying to connect
/etc/mysql/debian-start[3181]: FATAL ERROR: Upgrade failed

That’s just a few records on my personal experience regarding the hot-swapping/hot-plugging capabilities of SATA… Continue reading ‘hotplugging SATA harddisks in Linux’ »

want to know which files in /etc have been changed on your debian-like Linux system?

one part can be done with the package debsums, which compares the md5sums delivered with a debian-package with those of the current files:

$ sudo debsums -a -s
.
.
debsums: checksum mismatch apache2.2-common file /etc/apache2/sites-available/default
debsums: checksum mismatch apache2.2-common file /etc/apache2/ports.conf
.
.

Note 1: this does NOT cover configuration files that are not part of the .deb-package itself, e.g. those manually created by a user AND as well those built by a package’s configuration/post-install scripts. You have been warned!

Note 2: debsums can give hints about a compromised system, but it’s absolutely no guarantee that a non-suspicious output comes from a clean system – if the system’s compromised, an attacker could as well change the md5sums-database of a package (residing in /var/lib/dpkg/info/PKGNAME.md5sums)

wow, note this difference:

/opt/tivoli/tsm/client/ba/bin/dsmc incr /home/backups/
.
.
Total number of objects inspected:    2.314
.
.
Elapsed processing time:           00:00:01

and the same command without the trailing slash:

/opt/tivoli/tsm/client/ba/bin/dsmc incr /home/backups
.
.
Total number of objects inspected:   32.378
.
.
Elapsed processing time:           00:00:28

ever wondered where TSM stores its passwords? Documentation and lots of websites are talking about the file TSM.PWD, but where is it?

Voilà: /etc/adsm/TSM.PWD

just to remember how to test if a certain directory and its files are included in the backup using the TSM commandline interface:

./dsmc preview backup -console /path/to/dir/

delete one or more files from your backup (NOTE: the quotes in the second command are important, otherwise bash will expand the pattern and produce a list of files, which will confuse the TSM-client):

./dsmc delete backup /backups/mysql/mysqldump-complete-2010-01-20-1823.sql.gz
./dsmc delete backup '/backups/mysql/*.gz'

to create a user for doing automated backups of a MySQL installation that doesn’t have more than the necessary privileges, use the following statement:

GRANT RELOAD, SELECT, LOCK TABLES ON *.* TO 'backup'@'localhost' IDENTIFIED BY 'some_reasonable_password';