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EVA Florence 2012: Open low-cost HA cluster cloud

During these first hot-days in Florence, I've attended the EVA Florence 2012 conference, presenting a talk with Cristiano Corsani about a project for the National Library of Florence (BNCF), covering the deployment of a small Private Cloud using exclusively open source software, for serving internal and public BNCF services.

The proposed solution includes a virtualization stack running on commody hardware, using the Linux KVM hypervisor, managed by Proxmox 2.0 and with a GlusterFS shared storage.

I hope to write down some article to share the most interesting bits of this configuration, but time is not our friend.

cannot create zfs volume: one of the devices is part of an active md or lvm device

During the migration of a RAID1 mdadm on Ubuntu server to a ZFS mirror, I got stuck at the initial zfs volume creation with the following error:

cannot create 'tank': one or more vdevs refer to the same device, or one of the devices is part of an active md or lvm device

Obviously I've removed the device from the old mdadm array with:
sudo mdadm /dev/md3 --set-faulty /dev/sdb3
sudo mdadm /dev/md3 --remove /dev/sdb3

zram on Debian/Ubuntu for memory overcommitment

In recent Linux releases, it's available a tiny module called zram, that permits us to create RAM based block devices (named /dev/zramX), which will be kept in memory as compressed data. These ram-based block devices allow very fast I/O, and compression provides a reasonable amounts of memory saving.

We can use it as a drop-in replacement for the well-known tmpfs (used for speeding up compilation tasks or for /tmp), or better as a primary swap device, that will lead to virtually increase memory capacity, at the expense of a slightly increased CPU usage to compress/decompress the swapped data.

Nowadays RAM is very cheap, so why bother with compression? Because there are some situations where you can't upgrade memory (netbooks) or you want to over-commit real resources (virtualization hosts).

Open@BNCF - LinuxDay 2011 a Pisa

This year I've joined the LinuxDay of Pisa with a talk about my recent works in LiberSoft to the BNCF.

These includes:
* Desktop migration to Ubuntu Linux (10.04 LTS) with centralized login management (OpenLDAP) and shared /home with MooseFS;
* OpenNebula KVM-based Cloud with MooseFS as backend storage (and publishing of the relative transfer manager: https://github.com/libersoft/opennebula-tm-moosefs);
* GlusterFS-based infrastructure for the national italian legal deposit of books (italian article: http://www.bncf.firenze.sbn.it/pagina.php?id=212&rigamenu=Magazzini%20Di...)

Ubuntu fast boot and application launch with SSD Storage

Quick and dirty video of Ubuntu Natty 11.04 boot-up and applications launch of my Sony Vaio laptop with a Corsair 60GB SSD (http://twitpic.com/61y3n5)

Damned coincidence

SMART error (ErrorCount) detected on host: fs
Device: /dev/sdb, ATA error count increased from 0 to 74

=== START OF INFORMATION SECTION ===
Model Family: Seagate Barracuda 7200.11
Device Model: ST3500320AS
[..]
9 Power_On_Hours 0x0032 070 070 000 Old_age Always - 26286

OH wait: 26286 / 24 / 365 = 3,00068493 yr

This disk broke exactly after 3 years. WTF?

OpenNebula shared storage with MooseFS

I've written a post for the OpenNebula official blog about the usage of MooseFS as shared storage:

http://blog.opennebula.org/?p=1512

Help protecting privacy of internet users with unused bandwidth of your VPS

The internet nowadays isn't a privilege, is a right. Helping the world to get full access to it, it's a must for everyone.

If you own a server, a dedicated one or a VPS (like me, on Linode) you can use your spare bandwidth to help people that live in places where internet censorship it's the standard way to deal with information.

I've setup a tor relay to help the community to maintain a fast and stable link for tor users. To get minimal harassment, that I really don't have time to deal with, I allow no exit from my node, the tor traffic will pass on my node from a node to another one.

How to create a simple Activity Stream Weekly Digest using CCK and Views

I was researching for an easy method to publish as a single post my latest {month|week|day} activities on twitter aggregated by Activity Stream.

This is how I did it:

Welcome Drupal

Finally, I achieved to migrate my mini-tiny-shiny blog from the big-bug-bloat Wordpress platform to the fast-simply-powah Drupal.

For the import, I've used the wordpress_import module (if you use php5.3, check this), that use the WXR file generated by Wordpress->Tools->Export procedure.

Every feature I was used by on Wordpress, it's not lost because Drupal has a very large base of flexible modules. Here is a list of the most import modules I use on this site:

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