Resume sftp transfers

Of course there should be some way to resume transfers done via sftp.

Technically the way presented here is not sftp compliant (uses curl or, better, rsync --inplace).

But it's a way to start.

Note that I don't know if sftp subsystem supports resuming natively...

Heartbeat and two-nodes clusters

Heartbeat (from http://www.linux-ha.org/heartbeat/) is a nice software to manage linux high availability clusters. When you are in need to use a two-nodes cluster you want to prevent a situation known as "split-brain": when a node does not communicate with the other but neither two know which is the failing node.

This can lead to having the cluster drop all the services or having both nodes with the services on (in case of shared storage, this will lead to corruption unless the filesystem is clustered and supports multiple writes from multiple nodes). To make a long story short, split-brain is bad.

To counter this effect, you can use a ping host. Ping hosts are fake cluster members used by heartbeat to use the network connectivity as a mean to break ties in cluster node weight computations: if a node pings a ping host and the other doesn't, the hosts which pings is the winner. To make this configuration successful, you need an additional link between the nodes. This additional link could be serial or another ethernet.

To use ping hosts, this is the bare minimum configuration:

ping 10.10.10.10 # insert the ip of the ping host.
respawn hacluster /usr/lib64/heartbeat/ipfail # use /usr/lib on 32 bit hosts
apiauth ipfail gid=haclient uid=hacluster # this is for process security

But which ping host to chose? Use a reliable ping host; this can be the default gateway (if it's a router which has a very high uptime) or a local layer 3 switch. Don't use a server o a workstation!

Use hearbeat reload to configure the ping host without stopping the cluster and lose resources.

Linux first support for usb 3.0

The interesting news is that Linux could be the first mainstream OS to support Usb 3.0. Really, the support is already there if you mind building your own kernel.

The good news is that finally some female hacker comes to the surface. I felt rather fed of seeing Linus or Andrew Norton faces on articles (not minding Richard Stallman's). :)

Flashblock in Opera

I tried successfully the following operations to activate Flashblock in Opera (it worked with Opera 9.64 on Linux):

1. Download this file http://lexi.ucoz.ru/userjs/FlashBlock.js and put it in a directory of your choice
2. Go to Tools|Preferences|Advanced|Content|Javascript Options|User Javascript Files|Choose and choose the directory where you downloaded the javascript file.
3. Try it ;)

Note to Italian Opera users: you must use Strumenti|Preferenze (CTRL+F12)|Avanzate|Contenuti|Impostazioni per Javascript|Cartella dei file Javascript dell'utente|