DMRAID
- Overview
- Development packages
- Problem reporting
Overview
The purpose of dmraid is to arbitrate between the ATARAID on-disk metadata and the device-mapper need to name mapped devices and define mapping tables for them. Because the ATARAID metadata is vendor specific and the respective formats therefore all differ, an internal metadata format abtraction is necessary to translate into and derive the mapped device names and mapping tables content from. The ‘translators’ between the vendor formats and the internal format are called ‘metadata format handlers.’ One of them is needed for anygiven format supported by dmraid.
dmraid components:
- The dmraid tool which parses the command line and calls into
- The dmraid library with:
- – a metadata layer for the internal metadata format abstraction with generic properties to describe RAID devices and RAID sets with their sizes and offsets into devices, RAID layouts (e.g. RAID1) including arbitrary stacks of sets (e.g. RAID10)
- – metadata format handlers for every vendor specific solution (e.g. Highpoint, NVidia, VIA, . . . ) translating between those formats and the internal generic one
- – an activation layer doing devicemapper library calls
- – a display layer to show properties of block devices, RAID devices and RAID sets
- – a logging layer which handles output for verbosity and debug levels
- – a memory management layer (mainly for debugging purposes)
- – a locking layer to prevent parallel dmraid runs messing with the metadata
Command line interface: The dmraid CLI comprehends options to:
- activate or deactivate ATARAID sets
- select metadata formats
- display properties of
- – block devices
- – RAID devices
- – RAID sets
- – vendor specific metadata
- display help (command synopsis)
- list supported metadata formats
- dump vendor metadata and locations into files
- display the dmraid, dmraid library and the device-mapper versions
Development Packages
There are no serious issues known to the developers at the moment but it is wise to treat this as you would any development code.
Here’s whats available:
Two packages: one containing the latest userspace utility for "dmraid", the other is the latest Raid4/5 device driver:
(To be filled in by Heinz with latest code releases from http://people.redhat.com/heinzm/sw/dmraid/)
(To be filled in by Heinz with latest code releases from http://people.redhat.com/heinzm/sw/dm/dm-raid45/)
The "raid45" patches need to be applied to a 2.6.23.1 base kernel at the moment.
Reporting Problems with DMRAID Eventing
DMRAID is still under development and we appreciate your feedback and problem reports. Please send problem reports to the dm-devel & ataraid-list mailing lists. When reporting bugs, please try to include the following information:
- A description of events that led up to the problem (for e.g. "unable to activate/deactivate a raid volume because....")
- Any errors or messages that appeared on the terminal or in syslog at the time of the problem
- Version numbers of all the utilities used: dmraid and device-mapper userspace tools
If we are unable to resolve your issue with this information, we may ask you to collect further details from the system to aid debugging.