From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: Re: mismatch_cnt > 0 during initial sync? Date: Mon, 19 Jun 2017 07:34:49 +1000 Message-ID: <87shix3rpi.fsf@notabene.neil.brown.name> References: <9A8A3C34-EED0-42FF-B631-7AD1D6EAF9A2@stanford.edu> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha256; protocol="application/pgp-signature" Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Stephane Thiell , "linux-raid@vger.kernel.org" List-Id: linux-raid.ids --=-=-= Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Tue, Apr 25 2017, Stephane Thiell wrote: > I just did some tests and this seems normal if one of the raid disk previ= ously has some non-zero data. Perhaps there should be a note about that in= md(4) or elsewhere? (sorry if I missed it) From=20the perspective of md, the initial sync is no different from any other sync. It will count the number of mismatches that it finds and fixes. Feel free to post a patch for md.4 or elsewhere to clarify this. Thanks, NeilBrown > > Thanks, > > Stephan > >> On Apr 24, 2017, at 3:01 PM, Stephane Thiell wrot= e: >>=20 >>=20 >> Hi all, >>=20 >> Is it normal to get any mismatch_cnt > 0 during the initial sync? I just= created a few new new raid6 volumes, and one of them is showing an increas= ing number of mismatch_cnt during its initial resync. Nothing is visible in= the console nor after a smart short test (I also started a long test just = in case). >>=20 >>=20 >> $ mdadm --detail /dev/md7 >> /dev/md7: >> Version : 1.2 >> Creation Time : Mon Apr 24 10:07:18 2017 >> Raid Level : raid6 >> Array Size : 62511163904 (59615.29 GiB 64011.43 GB) >> Used Dev Size : 7813895488 (7451.91 GiB 8001.43 GB) >> Raid Devices : 10 >> Total Devices : 10 >> Persistence : Superblock is persistent >>=20 >> Intent Bitmap : Internal >>=20 >> Update Time : Mon Apr 24 14:52:12 2017 >> State : clean, resyncing=20 >> Active Devices : 10 >> Working Devices : 10 >> Failed Devices : 0 >> Spare Devices : 0 >>=20 >> Layout : left-symmetric >> Chunk Size : 64K >>=20 >> Resync Status : 24% complete >>=20 >> Name : oak-io1-s2:7 (local to host oak-io1-s2) >> UUID : 6ece9d71:a97f9497:4612ed73:44dfdc0a >> Events : 3308 >>=20 >> Number Major Minor RaidDevice State >> 0 253 62 0 active sync /dev/dm-62 >> 1 253 63 1 active sync /dev/dm-63 >> 2 253 72 2 active sync /dev/dm-72 >> 3 253 75 3 active sync /dev/dm-75 >> 4 253 89 4 active sync /dev/dm-89 >> 5 253 87 5 active sync /dev/dm-87 >> 6 253 119 6 active sync /dev/dm-119 >> 7 253 97 7 active sync /dev/dm-97 >> 8 253 103 8 active sync /dev/dm-103 >> 9 253 107 9 active sync /dev/dm-107 >>=20 >> $ cat /sys/block/md7/md/sync_completed >> 3795284824 / 15627790976 >>=20 >> $ cat /sys/block/md7/md/mismatch_cnt=20 >> 3424 >>=20 >> versions: >> mdadm-3.4-14.el7_3.1.x86_64 >> CentOS7 (3.10.0-514.10.2.el7_lustre.x86_64) >>=20 >> Thanks! >>=20 >> Stephan >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-raid" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEG8Yp69OQ2HB7X0l6Oeye3VZigbkFAllG8fsACgkQOeye3VZi gbms9Q//TwRf/3BsnunO6w2JumMIy05buR8d1Lcw4OUDScC+7Ar+FQloXTj8gHma wiKCd1jkJNeXlXfa7zdeK8iYtw9us4fg5xpjBJ1KUSd+5eIORDnaf5jAl/86vMh/ KScmL3YvMkjsOq71+LVS9DayXvB2Bjro8ZM2SCO+s6Zd7IcYH2GSfUfsa4LCC2St B6Svsx8DESaK3zs2/LeXy4oi5Skior3AXjf/+lIAZbGQ8tkp7SaXKwL9W4vVOhoF lQ3zllyjCu43tPhabUHIA+GT+pIhUSCwFFCvRDLHPniIXsnLfYEw9/rET/xENBsp 7aj6ApI2Y6g8uf9eLIPa4Rp7jcyDu+9O8tsuwWsFaykptBi8LzfZKQF1y/XqO0U1 fQESjFmjc4Rqx5+ZJVK2uYH+gGariij+4mHu84pfpnggUvBKVz58ON1gnfROe4oM d0sZVQA93gPN3eysR+dPfnONInsYPgqNyWStoihFsC5bV3liMglJaf/qcfRi9enG f5K+WRO7oxBdOqecDdQV+CrugLnuOxfR6ZnOUfzUcsAuzi8JcgWa5LpN+D4eTEQb ZNac2LwXuAMM6bekAPoMRBaEHQutl0lzZBo+VU6LO4IrI07HukEv5SAqtB3/Yo41 FBf7moX4RZvVynTfaNTK8Rhh1fKb+ZB5B/x9Nr+g4JIYGbaRHLw= =6UH6 -----END PGP SIGNATURE----- --=-=-=--