From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nikolay Kichukov Subject: Re: data scrubbing Date: Fri, 29 Jul 2011 16:25:39 +0300 Message-ID: <4E32B4D3.3030905@oldum.net> References: <4E327445.9080404@oldum.net> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Mikael Abrahamsson Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi, This is a good to know! Just performed a check on a raid1 and got: Jul 29 15:37:36 hanna64 mdadm[2277]: RebuildFinished event detected on md device /dev/md1, component device mismatches found: 128 So I presume those mismatches have now been rewritten to both disks successfully. Am I wrong there? cat /sys/block/md1/md/mismatch_cnt 128 Cheers, - -Nik On 07/29/2011 01:03 PM, Mikael Abrahamsson wrote: > On Fri, 29 Jul 2011, Nikolay Kichukov wrote: > >> For example is it good for raid1 array? > > Yes, it's good for all raid levels that have any kind of redundancy. You want to read the information on the drives > regularily to make sure it can still be read, and if it can't, it can be recomputed from parity and written. > > Otherwise not-often-read data might have an error on one drive, and then another drive fails and now when you try to > rebuild you don't have this data anywhere all of a sudden (RAID1 and RAID5), and you had no idea about this. > > Scrubbing is good, do it regularily (at least monthly). > -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQEcBAEBAgAGBQJOMrTTAAoJEDFLYVOGGjgXVPoH/0WDSWUhR8LvuaSizBBbbN48 iAWWsiA/fJr9DIO9+E1cTFXAqUOxsEY/iAJX7IVKAbS+R3/eYITHj0r6HajG3XnE wiqY3hoJU79aGBNOtxwAH8QeNtdGooVxL6TW0TRNFr/PFbWiBc2Aj2/aFizuqPHE EaYd1V02/i0wugWmGAFUAE81qG40jpuwq/B/KL18TDF8aayzj9T1PWLJh2QC3qJZ ugj708g34+X7yWY7C5gWYjHoX13IbyU+hbaM1Yrt7z0wLBFw+VxtNFDeWvOI/7zn E1c4DSmb4mAWL/CY8QlKP8oN5EkjS8o3VOz3UckkibiVqJw3X1msYZ52SY3UXeY= =LfWV -----END PGP SIGNATURE-----