From mboxrd@z Thu Jan  1 00:00:00 1970
From: Roman Mamedov <rm@romanrm.net>
Subject: Re: performance issue (was: Re: kernel: BUG: soft lockup - CPU#1
 stuck for 60s!)
Date: Sat, 24 Oct 2015 21:31:39 +0500
Message-ID: <20151024213139.5b20dec6@natsu>
References: <1092031595.20151015153830@oudeis.org>
	<87si5bvcj4.fsf@notabene.neil.brown.name>
	<43246687.20151024181541@oudeis.org>
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To: Rainer =?UTF-8?B?RsO8Z2Vuc3RlaW4=?= <rfu@oudeis.org>
Cc: Neil Brown <nfbrown@novell.com>, Linux-RAID <linux-raid@vger.kernel.org>
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On Sat, 24 Oct 2015 18:15:41 +0200
Rainer F=C3=BCgenstein <rfu@oudeis.org> wrote:

> hi,
>=20
> > I strongly recommend adding a write-intend bitmap
> >   mdadm --grow /dev/md0 --bitmap=3Dinternal
>=20
> I  did  as suggested, but now it feels like performance has dropped to
> about 1/4th of what it used to be before. since this system is already
> pretty slow by design, this is quite frustrating.

Use a higher bitmap-chunk size, such as 256M or more.

--=20
With respect,
Roman

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