Just to share this with list. ---------- Forwarded message ---------- From: Doug Ledford <dledford@xxxxxxxxxx> Date: Thu, Apr 1, 2010 at 11:34 PM Subject: Re: mounting component device of RAID1 with internal bitmap To: CoolCold <coolthecold@xxxxxxxxx> On 04/01/2010 03:25 PM, CoolCold wrote: > On Thu, Apr 1, 2010 at 10:39 PM, Doug Ledford <dledford@xxxxxxxxxx> wrote: >> On 04/01/2010 02:26 PM, CoolCold wrote: >>> On Thu, Apr 1, 2010 at 10:14 PM, Doug Ledford <dledford@xxxxxxxxxx> wrote: >>>> 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. When you do this, you make the different members >> of the raid array disagree on the contents of whatever file you >> modified. Depending on which disk the kernel reads from, you will get >> either the new or the old contents of the file. Any 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 <dledford@xxxxxxxxxx> GPG KeyID: CFBFF194 http://people.redhat.com/dledford Infiniband specific RPMs available at http://people.redhat.com/dledford/Infiniband -- Best regards, [COOLCOLD-RIPN]
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