Date: Tue, 31 Mar 2009 11:21:47 -0400 From: Juan Miscaro <jmiscaro@gmail.com> To: Ivan Voras <ivoras@freebsd.org> Cc: freebsd-questions@freebsd.org Subject: Re: Recovering a GEOM RAID0 array Message-ID: <d0626390903310821n794b01e1j440cb0b12df76cec@mail.gmail.com> In-Reply-To: <gqtb3f$br2$1@ger.gmane.org> References: <d0626390903301221o701f762ao18269ae6e212affa@mail.gmail.com> <gqt0rm$64m$1@ger.gmane.org> <d0626390903310522w67f09292t5148334ee3cd2a2d@mail.gmail.com> <gqt3ei$f77$1@ger.gmane.org> <d0626390903310621p5e6e71a9n38ec5b81f5780585@mail.gmail.com> <gqt6ib$q6c$1@ger.gmane.org> <d0626390903310721u21971567k99c94b01e0d57fe4@mail.gmail.com> <gqtb3f$br2$1@ger.gmane.org>
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--00163631053bea64ed04666bc17d Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable 2009/3/31 Ivan Voras <ivoras@freebsd.org>: > Juan Miscaro wrote: > >>> It looks like you created a both a fdisk partition table and a bsdlabel >>> partition table on the ad3 drive. If so, your data is probably already >>> corrupted. >> >> What is a generic configuration? =C2=A0Or can you explain how you come t= o >> that conclusion? > > RAID 0 means striping data across N drives (2 in your case), with a > fixed stripe size. From the information in kern.geom.confxml (which is > why gstripe list should work), your stripe size is 4 kB, which is good > for this purpose. This kind of setup is usually done with raw drives, > i.e. with GEOM_STRIPE: "gstripe label st0 ad1 ad3". After this, your > array is called stripe/st0 - this is where you create the file system, > etc. "Striping" means that each drive contains only a part of the data. > E.g. if you write 8 kB to the start of your array, the first 4 kB will > be written to ad1, the next 4 kB to ad3. Both smaller and larger > requests are handled logically. This means that the first sector on ad1 > contains the partition table of your array, if you partitioned it (and > it looks like you did). The first sector of ad3 contains whatever data > is at position 4096 in your array - probably nothing important because > your partitions start at 32 kB - 512. > > If you wrote only the partition table to ad3 then it's not a big deal - > it's useless but it may not corrupt anything important. If you proceeded > to to something else on ad3, then there could be problems. > >>> ad1 is also strangely partitioned but since it's your first drive in a >>> stripe this can be acceptable (it will contain the first sectors of the >>> array, including its partition tables). >>> >>>> # gstripe dump ad3 >>>> Can't read metadata from ad3: Invalid argument. >>>> Not fully done. >>> This can happen if the metadata on ad3 is corrupted. You'll need to dum= p >>> the last sector and inspect it to verify. >> >> I've never done that before. =C2=A0Can you be explicit? > > Using information from your previous posts, you should do this: > > # dd if=3D/dev/ad3 of=3Dad3last count=3D1 skip=3D625142447 > # hd ad3last > > Thanks for that great explanation. The file ad3last.txt is attached. -- jm --00163631053bea64ed04666bc17d Content-Type: text/plain; name="ad3last.txt" Content-Disposition: attachment; filename="ad3last.txt" Content-Transfer-Encoding: base64 X-Attachment-Id: f_fsyqk0k61 MDAwMDAwMDAgIDI0IDQ3IDQxIDQ2IDUyIDEwIDQxIDA4ICAwMCAwMCAwMCAwMCAwMCAwMCAwMCAw MCAgfCRHQUZSLkEuLi4uLi4uLi58CjAwMDAwMDEwICAwMCAwMCAwMCAwMCAwMCAwMCAwMCAwMCAg MDAgMDAgNmYgZTIgNDIgMjUgMDAgMDAgIHwuLi4uLi4uLi4ub++/vUIlLi58CjAwMDAwMDIwICAw MCAwMCAwMCAwOCAwMCAwMCAwMCAwMCAgMDAgMDAgMDAgMDAgMDAgMDAgMDAgMDAgIHwuLi4uLi4u Li4uLi4uLi4ufAowMDAwMDAzMCAgMDAgMDAgMDAgMDAgMDAgMDAgMDAgMDAgIDAwIDAwIDAwIDAw IDAwIDAwIDAwIDAwICB8Li4uLi4uLi4uLi4uLi4uLnwKKgowMDAwMDEwMCAgMjYgMzAgMzYgMmYg MzIgMzcgMmYgMzIgIDMwIDMwIDM2IDJkIDUwIDM0IDRkIDM4ICB8JjA2LzI3LzIwMDYtUDRNOHwK MDAwMDAxMTAgIDMwIDMwIDUwIDcyIDZmIDJkIDM4IDMyICAzMyAyZCAzNiA0MSAzNyA0YyAzNiA0 NyAgfDAwUHJvLTgyMy02QTdMNkd8CjAwMDAwMTIwICAwMCAwMCAwMCAwMCAwMCAwMCAwMCAwMCAg MDAgMDAgMDAgMDAgMDAgMDAgMDAgMDAgIHwuLi4uLi4uLi4uLi4uLi4ufAoqCjAwMDAwMjAwCg== --00163631053bea64ed04666bc17d--
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