From mboxrd@z Thu Jan  1 00:00:00 1970
From: NeilBrown <neilb@suse.com>
Subject: Re: Fwd: (user) Help needed: mdadm seems to constantly touch my disks
Date: Tue, 20 Dec 2016 10:39:26 +1100
Message-ID: <87inqftro1.fsf@notabene.neil.brown.name>
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On Mon, Dec 19 2016, Jure Erzno=C5=BEnik wrote:

> I have made two blktraces at the same time: one for md0 and one for a
> member of the array. I hope they will show something sensible.
>
> I dropped them here:
> http://expirebox.com/download/ee081fa4f85ffbd0bfad68e4ee257e11.html
>
> The file will be available for 48 hours or so they say.

Thanks.
The blktrace_md0.txt file shows several writes that originate from
   iscsi_trx

so it looks like 'md0' (or some other device that is built on it) is
being exported as an iscsi target.  Is that correct?

There are also some large (1024 sector) writes being generated about
once per second.  That is very clearly something being written to md0,
not something that md0 is doing itself.
They are generated by a kworker.  It might be iscsi related, but it
might be something else.

Try disabling the iscsi export and if the strange traffic still appears,
collect another blktrace (maybe for a bit longer - 30 seconds?).
Also please report output of
  ls -l /sys/block/md0/holders/
  fuser /dev/md0

when the problem is occurring.

NeilBrown

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