md device naming question

md device naming question

[maximilian attems]

hello,

working on initramfs i'd be curious to know what the /sys/block
entry of a /dev/md/NN device is. have a user request to support
it and no handy box using it.

i presume it may also be /sys/block/mdNN ?


thanks

-- 
maks

Re: md device naming question

[Nix]

On 19 Sep 2007, maximilian attems said:

> hello,
>
> working on initramfs i'd be curious to know what the /sys/block
> entry of a /dev/md/NN device is. have a user request to support
> it and no handy box using it.
>
> i presume it may also be /sys/block/mdNN ?

That's it, e.g. /sys/block/md0. Notable subdirectories include holders/
(block devices within the array, more than one if e.g. LVM is in use),
slaves/ (block devices making up the array) and md/ (RAID-specific
state).

-- 
`Some people don't think performance issues are "real bugs", and I think 
such people shouldn't be allowed to program.' --- Linus Torvalds

Re: md device naming question

[Michal Soltys]

Nix wrote:
> On 19 Sep 2007, maximilian attems said:
> 
>>
>> i presume it may also be /sys/block/mdNN ?
> 
> That's it, e.g. /sys/block/md0. Notable subdirectories include holders/
> (block devices within the array, more than one if e.g. LVM is in use),
> 

Also, if you mount the raid as a partitionable one, /sys/block/md_dNN ;

mdadm has pretty decent handling of all the names (check out auto options, 
both usable in mdadm.conf and from command line). Also from my experience, 
if you try to use udev on partitionable arrays, partition related uevents 
will be delayed until next mdadm invocation, or some partition related 
command (like fdisk).