From mboxrd@z Thu Jan 1 00:00:00 1970 From: CoolCold Subject: Fwd: mounting component device of RAID1 with internal bitmap Date: Fri, 2 Apr 2010 18:39:18 +0400 Message-ID: References: <4BB4E291.5090304@redhat.com> <4BB4E861.9020003@redhat.com> <4BB4F548.2090709@redhat.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary=0016e659f984b7c00b048341f1be Return-path: In-Reply-To: <4BB4F548.2090709@redhat.com> Sender: linux-raid-owner@vger.kernel.org To: Linux RAID List-Id: linux-raid.ids --0016e659f984b7c00b048341f1be Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Just to share this with list. ---------- Forwarded message ---------- From: Doug Ledford Date: Thu, Apr 1, 2010 at 11:34 PM Subject: Re: mounting component device of RAID1 with internal bitmap To: CoolCold On 04/01/2010 03:25 PM, CoolCold wrote: > On Thu, Apr 1, 2010 at 10:39 PM, Doug Ledford wrote= : >> On 04/01/2010 02:26 PM, CoolCold wrote: >>> On Thu, Apr 1, 2010 at 10:14 PM, Doug Ledford wro= te: >>>> On 04/01/2010 01:47 PM, CoolCold wrote: >>>>> Hello! >>>>> For raid1 array with metadata 0.90 it is possible to mount component >>>>> (let's say /dev/sda1) as usual FS, fix smth, /etc/fstab for example, >>>>> unmount and then assamble arary. >>>> >>>> At which point you have just corrupted your array. >>> I've did such operation several times and it worked fine..I'll do some >>> checks and report later. >> >> Because you got lucky. =A0When you do this, you make the different membe= rs >> of the raid array disagree on the contents of whatever file you >> modified. =A0Depending on which disk the kernel reads from, you will get >> either the new or the old contents of the file. =A0Any time you mount a >> component device and modify it, you *must* force a resync from that >> component to all other components or you *will* have a corrupt array. >> When that corruption will crop up to bite you in the ass is up to random >> chance. > Ah, ofcourse recync is ok , i wanted to know will this break _raid_ > (eg erase some metadata) itself, not actual data on top of it. For 0.9 > it is said in man that it stored at the end of device, but what about > bitmaps? are they at the end too ? The bitmaps are outside of the regular filesystem area, so they can't be harmed by mounting the filesystem. -- Doug Ledford =A0 =A0 =A0 =A0 =A0 =A0 =A0GPG KeyID: CFBFF194 =A0 =A0 =A0 =A0 =A0 =A0 =A0http://people.redhat.com/dledford Infiniband specific RPMs available at =A0 =A0 =A0 =A0 =A0 =A0 =A0http://people.redhat.com/dledford/Infiniband --=20 Best regards, [COOLCOLD-RIPN] --0016e659f984b7c00b048341f1be Content-Type: application/pgp-signature; name="signature.asc" Content-Disposition: attachment; filename="signature.asc" Content-Transfer-Encoding: base64 X-Attachment-Id: 0.1 LS0tLS1CRUdJTiBQR1AgU0lHTkFUVVJFLS0tLS0KVmVyc2lvbjogR251UEcgdjEuNC4xMCAoR05V L0xpbnV4KQoKaUVZRUFSRUNBQVlGQWt1MDlVZ0FDZ2tRZzZXeWxNKy84WlFaRUFDZU9pUDFPODc4 bE5rcSt2dEIrVkpiQTBNcwpkaVVBbjBkb3dnTzFxWHNRZHFHZ00yUVpkOU80LzRjSwo9U2NUcgot LS0tLUVORCBQR1AgU0lHTkFUVVJFLS0tLS0K --0016e659f984b7c00b048341f1be--