Well, not much. I’m a SAP Basis administrator that’s interested in learning how operating systems work on all levels.

Despite my job is done with one of the most private representation of closed source products, I’m still amazed at how real open source projects work, allowing people to solve their problems or needs with the work others offer in a free way.


Since I wanted to boot vkernels from host directories without using NFS and we had no support for that, dirfs project started in the end of August, 2012. This idea comes from some discussions in #dragonflybsd channel on EFnet where it was indicated sort of a filesystem was needed that provided translation between vkernel kernel calls to VFS API and system calls directly to the host. This document is to keep track on how I got started, what problems I encountered and any other ranting I may think of. [Read More]


What is hammer-backup? This script operates HAMMER PFSes and dumps its contents for backup purposes. It uses mirror-read directive (see ‘man 8 hammer’) to perform a dump to stdout that is redirected to a file with or without compression. It can take two types of backup: Full: Where ALL the data of the PFS is sent to a file. Inremental: It requires a previous full backup. Additionally to the backup data itself, it creates a . [Read More]


Currently DragonFly BSD has an in-kernel iSCSI initatior which is the client part of the iSCSI protocol. I’ve tested very basic functionality like attaching disks and formatting them with UFS and HAMMER without problems but there are problems with disconnections, so be aware of this before using it in productive environments. Danny Braniss is the author of iscsi_initiator for FreeBSD. He keeps all the revisions of it here. It was ported to DragonFly BSD by Antonio Huete Jimenez with help of others, specially Matthew Dillon. [Read More]


libhammer and its very basic functionality (say 10%) has been pushed to DragonFly BSD tree.

You can find it here.


DragonFly BSD Old/deprecated libhammer is an attempt to collect the most basic functions to interact with the HAMMER filesystem. hammer-backup would be a backup system based upon HAMMER FS snapshots. iSCSI is a section with all the related information about iSCSI protocol and DragonFly BSD. dirfs is a userland filesystem for vkernel that provides the ability to mount any host directory. Final goal is to be able to dirfs root mount for vkernel. [Read More]