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Bug#361674: problems with using "mdrun /dev"



Package: initramfs-tools
Version: 0.59b

hi... if you're going to use "mdrun /dev" and launch all arrays during the 
initrd then you should also include mdadm.conf -- because otherwise you 
may end up starting arrays on the wrong minors... or even worse, if 
someone is using partitioned md then you'll miss the partitions entirely.  
if you include mdadm.conf these problems will probably be avoided.

however i'm not so keen on running all the arrays from initrd for the 
following reasons:

- if i plug in former md drives from another system for recovery or reuse 
purposes the initramfs-tools initrd will try launching the raids it 
finds... which is almost guaranteed to cause preferred minor conflicts.  
including mdadm.conf may or may not help this depending on device 
ordering.

- "mdrun /dev" makes it impossible for me to have an array which *isn't* 
started at boot... there are several failure recovery scenarios where i 
want an array which i start manually or not at all (i.e. start it 
read-only) because i need to avoid any writes at all, and especially need 
to avoid md resync.

- "mdrun /dev" starts resync at boot time -- which can thrash the system 
with i/o and slow down the boot significantly... and it's too early to 
have /etc/sysctl.conf override the speed_limit_max to throttle the 
recovery in order to get past startup.

anyhow... i'd really recommend starting just the root raid... and 
including mdadm.conf in case the user is trying to do root on partitioned 
md.

thanks
-dean



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