Monday, January 23, 2012

Install cProfile on debian 6.0.3 (squeeze)

So you just seen this when tried to profile something on debian squeeze

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.6/", line 36, in run
    result = prof.print_stats(sort)
  File "/usr/lib/python2.6/", line 80, in print_stats
    import pstats
ImportError: No module named pstats

Well all is need to fix it is to enable a repository and then install python-profile

echo 'deb squeeze main non-free' >> /etc/apt/sources.list
# replace .ca. with your country code
apt-get update
aptitude install  python-profiler

>>> import cProfile
>>> def f():
...     print 'called'
         3 function calls in 0.000 CPU seconds

   Ordered by: standard name

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
        1    0.000    0.000    0.000    0.000 :1(f)
        1    0.000    0.000    0.000    0.000 :1()
        1    0.000    0.000    0.000    0.000 {method 'disable' of '_lsprof.Profiler' objects}

Thursday, January 12, 2012

MySQL backup in time

Run mysqldump on master database (needs to have innodb)

# replication point in time
mysqldump --single-transaction --flush-logs \
--master-data=2 --all-databases > backup.sql

# Note the position and the log file from the backup.sql and insert it into the slave</>

shell# mysql -u USER -p PASS
mysql> stop slave;
shell# mysql < backup.sql
shell# mysql -u USER -p PASS 
mysql> CHANGE MASTER TO MASTER_LOG_FILE='the_log_file_written_into_dump',
mysql> MASTER_LOG_POS = xxx ;
mysql> start slave;

Create storage infrastructure with libvirt

Libvirt is defacto library to manage virtual machines. This will show how you can create a storage pool that can be used later to allocate space for vms.

my storage space is located under /storage and the type is a regular directory as i want to store image files in there. this is low performance but will do for my dev machines.

first you need to create the directory

mkdir /storage

# then you need to have an xml file as follow - see type is dir and path is /storage

<pool type="dir">


# than go into virsh and define the new pool - define will make the pool  persistent into the /etc/libvirt/

virsh# pool-list
virsh# pool-autostart pool_name
<capacity unit="T">1</capacity>