The FreeBSD Documentation Project $P4: //depot/user/simon/geomfaq/article.sgml#6 $ 2004 The FreeBSD Documentation Project &tm-attrib.freebsd; &tm-attrib.general; This is the FAQ for GEOM. At the moment this FAQ is being maintained by &a.simon;. It will be moved to the &os; Architecture Handbook when it has a bit more content. This document is very much Work In Progress at the moment, so you will almost certainly find spelling/gramma/content errors.

Welcome to the GEOM FAQ! Every effort has been made to make this FAQ as informative as possible; if you have any suggestions as to how it may be improved, please feel free to mail them to the &a.geom; or &a.simon;. What is GEOM? The GEOM framework provides an infrastructure in which classes can perform transformations on disk I/O requests on their path from the upper kernel to the device drivers and back. Translations provided by current GEOM classes include disk layout and partitioning schemes, such as FDISK slices, GPT slices, and BSD partitions. Also, GEOM includes a number of more complex classes implementing servies such as UFS volume labeling, disk mirroring, and RAID. GEOM provides abstractions making it easy to implement new disk layouts, as well as providing important infrastructure for implementing more complex storage services, such as RAID and logical volume management. These include standard mechanisms for auto-discovery, I/O request flow management, composition, and management services. What documentation exists for GEOM? GEOM manual page &man.geom.4;. &a.phk;s GEOM tutorial for BSDcon 2003 - . &a.phk;s old introduction about what GEOM should be, before it was implemented: "Geometry" - an idea - . &a.phk;s FreeBSD Kernel Blueprints articles in DĉmonNews: Userland/kernel interfaces and Complex and extensible configuration interfaces. &a.pjd; has created manual pages for the GEOM kernel API. They are included in &os; 5.2-CURRENT. See: &man.DECLARE.GEOM.CLASS.9;, &man.g.attach.9;, &man.g.bio.9;, &man.g.consumer.9;, &man.g.data.9;, &man.g.event.9;, &man.g.geom.9;, &man.g.provider.9;, &man.g.provider.by.name.9;, and &man.g.wither.geom.9;. The source GEOM code - src/sys/geom. Where can I ask questions about GEOM? The &a.geom; (&a.geom.name;) exists for discussions about the GEOM framework and about implementations of GEOM modules. What is GBDE ? GBDE is Geom Based Disk Encryption. It is a cold disk encryption system. Unlike encrypted file systems GBDE works on the disk level, meaning that it is possible put anything on top of the encrypted device. Normally an encrypted device would be used for a file system (normal UFS/&man.ffs.7;) or a swap device, but you can use the device like any other normal raw disk device. What documentation exists for GBDE? The GBDE manual pages &man.gbde.4; and &man.gbde.8;. &a.phk;s GBDE paper for BSDcon 2003 - . &a.phk;s GBDE slides for BSDcon 2003 - . The FreeBSD Handbook Encrypting Disk Partitions section. Does GBDE support cryto hardware acceleration? At the moment no, but work is in progress to use the AES support in the Hi/fn 7955 chip. These chips can be found on the Soekris Engineering vpn1401 boards, and probably boards by other manufactures as well. What is the status of the GEOMification of &man.vinum.4; Lukas Ertl l.ertl@univie.ac.at has some initial code which is still at a very early stage, but some parts does work. It can be found at . This thread on the &a.hackers; and the &a.current; contains some thoughts on the future of software RAID in &os;.