Speedup FreeNET Startup (entropy)

fbarriga — Sun, 29 Nov 2009 17:08:04 +0000

FreeNET needs some good random data to startup.
When the node start it can take some time getting this data and this message is going to appear:

Freenet is starting up
Not enough entropy is available!
There isn’t enough entropy available on your system… Freenet won’t start until it can gather enough.

To avoid this or speedup the process you can generate some entropy doing some random hard disk drive seeks. You can use this little program to do that (and also know the average random seek of your hard disk drive):

user@computer:$ wget http://www.linuxinsight.com/files/seeker.c

user@computer:$ gcc -O3 seeker.c -o seeker

user@computer:$ sudo ./seeker /dev/sda
Benchmarking /dev/sda [238475MB], wait 30 seconds.............................
Results: 54 seeks/second, 18.46 ms random access time

Speedup FreeNET on SunOS/Solaris/BSD/Linux

fbarriga — Sun, 29 Nov 2009 16:40:53 +0000

If you have used FreeNET you can notice that if you have to many persistent downloads (~ more than 500) your CPU is going to get very busy. That happens because node.db4o (the file where persistent downloads queue are stored) is updated extremely frequently. On every update the cache of this file is flushed to filesystem making a process delay (waiting I/O).
A little trick to avoid this is to install FreeNET then move it to a RAM memory Filesystem (tmpfs) so the file updates are not going to slow down the process (wait I/O caused by random writes).

To create the RAM filesystem you need to execute:

user@computer:$ sudo mkdir /tmpfs

user@computer:$ sudo mount tmpfs -o size=2g,uid=user,gid=user_group,mode=755 -t tmpfs /tmpfs

Then you can check if all is ok:

user@computer:$ df -h | grep \/tmpfs
tmpfs 2.0G 344M 1.7G 17% /tmpfs

Now copy the FreeNET files to this filesystem:

user@computer:$ mkdir /tmpfs/FreeNET

user@computer:$ cp -Rf ~/freenet_installation/* /tmpfs/FreeNET

The datastore and persistent-temp-XXXX (replace XXXXX with the corresponding number) directories usually grows a lot so you need to put somewhere else and make the symbolic links:

user@computer:$ cd /tmpfs/FreeNET

user@computer:$ ln -s ~/freenet_data/datastore .

user@computer:$ ln -s ~/freenet_data/persistent-temp-XXXX .

Note: Is a good idea to put that directories in a RAID-0 block device.

Now you are ready to take advantages of using tmpfs.
To avoid some steps you can write an small script and/or put the creation of /tmpfs on /etc/fstab:

user@computer:$ echo "tmpfs /tmpfs tmpfs size=2g,uid=user,gid=user_group,mode=755 0 0" >> /etc/fstab

Also you may want to disable logger because it generate some I/O. Edit freenet.ini:

user@computer:$ echo "logger.enabled=false" >> freenet.ini

Remember to backup and then restore /tmpfs/FreeNET on every shutdown/boot !

Felipe Barriga Richards » FreeNET

Speedup FreeNET Startup (entropy)

Speedup FreeNET on SunOS/Solaris/BSD/Linux