From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: Re: frequent disk activity with mdadm-3.3 Date: Mon, 15 Sep 2014 10:18:30 +1000 Message-ID: <20140915101830.3c85d423@notabene.brown> References: <20140912082403.549fc298@notabene.brown> <164CD08B-99CA-4007-855A-7B0561B4EC76@gmail.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; boundary="Sig_/NW1RUvwM7D//c8NTDJSG/iD"; protocol="application/pgp-signature" Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Marco Schindler Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids --Sig_/NW1RUvwM7D//c8NTDJSG/iD Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On Fri, 12 Sep 2014 14:15:35 +0200 Marco Schindler wrote: > ok, that=E2=80=99s interesting. > the process id is _not_ mdadm daemon and it looks like the spindown itsel= f is triggering the process. >=20 > ps ax | grep mdadm > 28956 ? Ss 0:00 mdadm --monitor --scan --daemonise --pid-file = /var/run/mdadm.pid --syslog >=20 > grep sda /var/log/messages > Sep 12 13:55:04 alina spindown: sda is now inactive. > Sep 12 13:55:09 alina kernel: mdadm(29737): READ block 3907028992 on sda = (8 sectors) > Sep 12 13:55:17 alina kernel: mdadm(29737): READ block 3907029152 on sda = (8 sectors) > Sep 12 13:55:26 alina kernel: mdadm(29737): READ block 0 on sda (8 sector= s) > Sep 12 13:55:26 alina kernel: mdadm(29737): READ block 8 on sda (8 sector= s) > Sep 12 13:55:26 alina kernel: mdadm(29737): READ block 8 on sda (8 sector= s) > Sep 12 13:55:26 alina kernel: mdadm(29737): READ block 3907029167 on sda = (1 sectors) > Sep 12 13:55:26 alina kernel: mdadm(29737): READ block 3907029166 on sda = (1 sectors) > Sep 12 13:55:26 alina kernel: mdadm(29737): READ block 0 on sda (1 sector= s) > Sep 12 13:55:26 alina kernel: mdadm(29737): READ block 0 on sda (1 sector= s) > Sep 12 13:55:26 alina kernel: mdadm(29737): READ block 3907029152 on sda = (8 sectors) > Sep 12 13:55:26 alina kernel: mdadm(29737): READ block 0 on sda (8 sector= s) > Sep 12 13:55:26 alina kernel: mdadm(29737): READ block 8 on sda (8 sector= s) > Sep 12 13:55:26 alina kernel: mdadm(29737): READ block 8 on sda (8 sector= s) > Sep 12 13:55:26 alina kernel: mdadm(29737): READ block 8 on sda (8 sector= s) > Sep 12 13:56:12 alina spindown: sda is now active. It would help to get "udevadm monitor" info to correlate with this. Presumably some uevent is generated when the spindown happens. udev might respond to this by reading from the device, which defeats the purpose... >=20 > here=E2=80=99s the output of blktrace -d /dev/sda during that time. > https://dl.dropboxusercontent.com/u/3464720/blktrace.tar.bz2 That suggest that something is reading the metadata from the device almost constantly. Mostly a 'kworker' thread. I don't know what would cause that. Let's look at the 'udevadm monitor' trace first and see what that shows. NeilBrown --Sig_/NW1RUvwM7D//c8NTDJSG/iD Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIVAwUBVBYwVjnsnt1WYoG5AQItjxAAh7WtecPxaD0j0r3RVNvPL/4FttJz1Ml7 PdATKOr6ESBr27oG74KRbHEawv9ZOHM7lhgYSDBYUYVWlCTDK8JxeFwvDCvHYtFN M1St5I+CqmbMvreKkRP5pPV5PNvBIZ3/ehYDcJF6+41ob54tS/BeFlYMo42RBEKU 1W8TGutERgsqwPB+ixMyMkVPzSIFjLGyhgRZlOs6tqF+7++l5gH39ef9Ju7uDsLK VMEdsak8kR3KJqZUrHC7NZ6+KhpChFiyM9SrG4vMmSNQnf1eqbLyG2uCyhqmnrul 4bYcJOjPo511DFj6qjoQ5FxnchIblKRb+GWTUXNhEpr12sRNtcyc3MXImY5G/p5p WHT8+1jvj2BM6p/sI3A5KDQHl2hc+gKh0erkD3+518ByRKa5FpKCEh4pTGVIJiub hGsN+rsJaqYY6GSWdTmmGYHsClUpYJ3L7hnjuxrNTXcfs3DtxoDM7nWd+Aunt0j/ d5pBi4TmFQZHgZLuaogpJB1jNOh+r8wk1nrvjMlyKdHWdiZI/fM1Dxmx3Z5EKZHe MYMxoSUAtMHTbQc0R8XU60HSTQwVWr7RdrqCqcBk4Xwa1s5yefcWiz8QznhsxCjX cwdF7x0Q+w1Lbtld2BVXBRpy6LiTJpt1lxkVMywsPEn34LyUke2ODdiABIbmsn5N 0Aq48uz0fpU= =GTlQ -----END PGP SIGNATURE----- --Sig_/NW1RUvwM7D//c8NTDJSG/iD--