From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roman Mamedov Subject: Re: strange problem with raid6 read errors on active non-degraded array Date: Wed, 2 Jul 2014 15:52:24 +0600 Message-ID: <20140702155224.072d09ef@natsu> References: <20140702103241.Horde.iempNvYRo99Ts9G5Op7ionA@webmail.aeiou.pt> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/xPzoLQL62zMV6Tm/AM2gvO_"; protocol="application/pgp-signature" Return-path: In-Reply-To: <20140702103241.Horde.iempNvYRo99Ts9G5Op7ionA@webmail.aeiou.pt> Sender: linux-raid-owner@vger.kernel.org To: Pedro Teixeira Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids --Sig_/xPzoLQL62zMV6Tm/AM2gvO_ Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Wed, 02 Jul 2014 10:32:41 +0100 Pedro Teixeira wrote: > - I'm having the following problem on a raid6 md volume consisting og =20 > 16 1TB Seagtes SSHD's. ( using kernel 3.15.3 or 3.14.0 ) mdadm is 3.3. >=20 > - every time I run a fsck.ext4 I will get the exact same errors ( =20 > ...short read ). Forcing a repair on the md0 volume shows no errors =20 > and completes without problems. All disks are active and the volume is =20 > not degraded, still I can't get rid of the short errors on those 16 =20 > blocks and when the filesystem is mounted the read errors will come up =20 > from time to time as they are probably in use. Are you sure that Ext4 in your kernel, and all tools that you use with it (= such as the fsck) really support 16 TB filesystems? I recall there have been some semi-obvious problems with that. Try a different FS, e.g. XFS or Btrfs inst= ead of Ext4. > - If I try to read those blocks with DD ( dd if=3D/dev/md0 of=3Dtest.tx= t =20 > seek=3D458227712 count=3D6 bs=3D4096 ) it will instantly create a 1.8T fi= le =20 > but the file doesn't appear to have nothing on it ( and the file =20 > doesn't take the 1.8T on disk as the disk is much smaller ) > root@nas3:/# dd if=3D/dev/md0 of=3Dteste.txt seek=3D458227712 count=3D6 = bs=3D4096 > 6+0 records in > 6+0 records out > 24576 bytes (25 kB) copied, 0.0019239 s, 12.8 MB/s > root@nas3:/# ls -lah teste.txt > -rw-r--r-- 1 root root 1.8T Jul 2 10:22 teste.txt Here you need to use skip=3D, not seek=3D. See "man dd". --=20 With respect, Roman --Sig_/xPzoLQL62zMV6Tm/AM2gvO_ Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iEYEARECAAYFAlOz1lgACgkQTLKSvz+PZwizxQCdH5I7GUhltXi2Fg3vVUc+LTEQ 7lsAn1E0Rwyhy8HdoFaQmTl1+OGlDNI1 =j+8s -----END PGP SIGNATURE----- --Sig_/xPzoLQL62zMV6Tm/AM2gvO_--