Converting RAID1 + LVM (Fedora Core) To EVMS (Enterprise Volume Management System) Experiences…
By Angsuman Chakraborty, Gaea News NetworkMonday, September 3, 2007
I currently use RAID1 with LVM on Fedora Core including RAID 1 on boot partition. This provides a fully redundant storage system with the ability to expand volume size in future. However RAID & LVM has to be managed from command line tools like mdadm in raidtools package. EVMS (Enterprise Volume Management System) on the other hand provides a single, unified system for handling all of your storage management tasks. EVMS recognizes all of the disks on your system and allows for a variety of partitioning schemes. Software-RAID and logical volume groups can be managed in EVMS. Filesystems can be created and checked, and are automatically updated when changes are made to the underlying volumes. With EVMS, there is no longer a need for several individual utilities for performing each of these tasks.
In short EVMS is LVM on steroids (say methyl prednisolone 20mg BD).
In order to make the transition to EVMS as smooth as possible, EVMS includes compatibility with a number of existing storage and volume management systems. Currently, EVMS recognizes:
- All locally attached disks
- DOS-style disk partitions (used extensively on Linux systems)
- GPT disk partitions (mainly used on IA-64)
- S/390 disk partitions (CDL/LDL)
- BSD disk partitions
- Macintosh disk partitions
- Linux MD/Software-RAID devices
- Linux LVM volume groups and logical volumes (versions 1 and 2)
In addition to providing compatibility with existing systems, EVMS also provides new functionality that can be built on top of any of the above “volumes” that EVMS already recognizes. Features that are currently included are:
- Bad Block Relocation
- Linear Drive Linking
- Generic Snapshotting
It looks like it will support my configuration too. However I couldn’t find much commentary on experiences of other users.
Additionally it looks like 2.6 kernel users may have to apply the bd-claim patch among other alternatives.
My other concern is that the last stable version of EVMS (2.5.5) is from February 2006.
Have you tried converting to EVMS? What is your experience with EVMS versus traditional RAID + LVM configuration on Linux.
Tags: Hard Disk Crash Recovery
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May 31, 2008: 12:00 am
I found your blog, looking for commentaries on how to do the same with FC8. I have used EVMS on several Gentoo systems I have built. In particular I like to use the bad block replacement segment manager (bbr_seg) for data safety reasons; simply because I have found the ability of S.M.A.R.T. capable hard drives to be not that smart after all. Occasional bad blocks are inevitable and the ability to mark bad blocks has been removed from the more recent file-systems. I have found the bd_claim_patch to be unnecessary as long as you use evms initrd and mount all devices using the evms device nodes. I’m rebuilding a system that was running FC3 without EVMS, and was looking to add EVMS this time around, but I don’t want to spend several days on a gentoo install, and was looking at various distro’s capabilities to do manual partition configurations as part of their alternate install procedures. Did you, try your EVMS install? Les |
LesCoke