User:Gervai/Raid and LVM hook

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Contents 1 Raid + LVM 2 See also 3 Prerequisites 4 The source 5 Install 6 Configure 6.1 Full Example 7 TODO and FIXMEs

Raid + LVM

This is a code based on User:Svamberg/Software RAID which provides support for softraid but no LVM, so I added LVM. This approach works with recent FAI (unlike Setup harddisks 2).

See also

Please read User:Svamberg/Software RAID first.

Prerequisites

Apart from what already has been said I had some problems which should have been addressed:

• stock grub install doesn't really work under XFS, because grub-install code is still crappy (and seems that it is bound to stay that way). See Debian bugreport about it, and patch your grub-install, otherwise expect hung installs on xfs_freeze.
• install dmsetup, mdadm, lvm2 packages into nfsroot as well as into the clients
• install xfsprogs for xfs into client, if you want to use it (why not, it's nice)
• force loading modules raidX and dm-mod, probably in .../config/class/FAIBASE.var (or any class you prefer)

• You're not advised to put root filesystem on LVM because you may well end up with an unstartable system. (LVM is a userland system so it's not available at kernel startup time unless you're using a working initrd boot. Be prepared to fiddle with it and worry at every kernel upgrade.) Very few rescue CDs support it I belive, very few boot managers support it I believe. I've struggled with it for a while then decided not to do it. YMMW :-)

The source

It is available here.

Install

• Put the code into $FAI/hooks/mountdisks.SW_RAID
• Save this to $FAI/hooks/mountdisks.SW_RAID.source (instead of what's on Michal Svamberg's page!)

#!/bin/sh                                                                                                                                                      
. $LOGDIR/disk_var.sh         

• add class SW_RAID to your $FAI/class/ configuration

Configure

Raid is configured as Michal described.

LVM follows this syntax:

LVM_VG_CONFIG=vgname[[vgoptions]]=deviceA[,deviceB[,...]]                                                                                                     
                                                                                                                                                            
LVM_LV_CONFIG=vgname/lvname[[lvoption [lvoption ...]]]=size:mountpoint                                                                                          
         :[filesystem]:[mountoptions]     

Full Example

# define raid array                                                                                                                                           
SW_RAID_CONFIG="                                                                                                                                              
md0[mirror]=/dev/sda1,/dev/sdb1:/:xfs:rw:boot                                                                                                                 
md1[mirror]=/dev/sda6,/dev/sdb6:/var:xfs::                                                                                                                    
"                                                                                                                                                             
                                                                                                                                                              
# define volume groups                                                                                                                                        
LVM_VG_CONFIG="                                                                                                                                               
vol0[]=/dev/md1                                                                                                                                               
"                                                                                                                                                             
                                                                                                                                                              
# define logical volumes                                                                                                                                      
LVM_LV_CONFIG="                                                                                                                                               
vol0/var[-n var        ]=2G:/var:xfs:                                                                                                                         
vol0/var-log[-n var-log]=5G:/var/log:xfs:                                                                                                                     
vol0/home[-n home      ]=1G:/home:xfs:                                                                                                                        
vol0/tmp[-n tmp        ]=2G:/tmp:xfs:                                                                                                                         
vol0/usr[-n usr        ]=4G:/usr:xfs:                                                                                                                         
"                                             

TODO and FIXMEs

• Should handle 'disk1' instead of hardwired devices somehow
• Should verify user input (duplicate devices, duplicate vg/lv names, etc.)
• Should extend config with other options like boot, etc (I don't need them right now)