stopped array, but /sys/block/mdN still exists.

stopped array, but /sys/block/mdN still exists.

[Jon Nelson]

This isn't a high priority issue or anything, but I'm curious:

I --stop(ped) an array but /sys/block/md2 remained largely populated.
Is that intentional?

-- 
Jon

Re: stopped array, but /sys/block/mdN still exists.

[Neil Brown]

On Wednesday January 2, jnelson-linux-raid@jamponi.net wrote:
> This isn't a high priority issue or anything, but I'm curious:
> 
> I --stop(ped) an array but /sys/block/md2 remained largely populated.
> Is that intentional?

It is expected.
Because of the way that md devices are created (just open the
device-special file), it is very hard to make them disappear in a
race-free manner.  I tried once and failed.  It is probably getting
close to trying again, but as you say: it isn't a high priority issue.

NeilBrown

Re: stopped array, but /sys/block/mdN still exists.

[Neil Brown]

On Thursday January 3, davidsen@tmr.com wrote:
> 
> So what happens if I try to _use_ that /sys entry? For instance run a 
> script which reads data, or sets the stripe_cache_size higher, or 
> whatever? Do I get back status, ignored, or system issues?

Try it:-)

The stripe_cache_size attributes will disappear (it is easy to remove
attributes, and stripe_cache_size is only meaningful for certain raid
levels).
Other attributes will return 0 or some equivalent, though I think
chunk_size will have the old value.

NeilBrown