Re: [CentOS] Moving from mdadm raid 0 to single disk
On 1/11/22 8:50 PM, Alexandre Leonenko wrote: Thanks, That's what I'll probably be doing then. Great. Don't miss Jonathan's answers. His are very instructive and with deep insights, as always. Valeri Alex From: CentOS on behalf of Valeri Galtsev Sent: Tuesday, January 11, 2022 5:21 PM To: centos@centos.org Subject: Re: [CentOS] Moving from mdadm raid 0 to single disk On 1/11/22 8:11 PM, Alexandre Leonenko wrote: Hey all, Hopefully a quick question. I'm going to move the filesystem of a raid 0 mdadm to a single disk. The filesystem is just a data drive, can I just dd if=/dev/md0 of=/dev/sdc ? Or should I rather rsync the files directly? I would [partition disk; make new filesystem, mount, then] use rsync. You avoid copying nuisances if there are any on old filesystem. You avoid the need to resize partition on new disk, and expand filesystem. You avoid waste of time copying empty space. You can have different disklabel (it old was MSDOS and you want GPT). And few other things. I hope, thins helps. Valeri Regards, Alex ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos -- Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247 ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos -- Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247 ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Moving from mdadm raid 0 to single disk
Thanks, That's what I'll probably be doing then. Alex From: CentOS on behalf of Valeri Galtsev Sent: Tuesday, January 11, 2022 5:21 PM To: centos@centos.org Subject: Re: [CentOS] Moving from mdadm raid 0 to single disk On 1/11/22 8:11 PM, Alexandre Leonenko wrote: > Hey all, > > Hopefully a quick question. I'm going to move the filesystem of a raid 0 > mdadm to a single disk. > The filesystem is just a data drive, can I just dd if=/dev/md0 of=/dev/sdc ? > Or should I rather rsync the files directly? I would [partition disk; make new filesystem, mount, then] use rsync. You avoid copying nuisances if there are any on old filesystem. You avoid the need to resize partition on new disk, and expand filesystem. You avoid waste of time copying empty space. You can have different disklabel (it old was MSDOS and you want GPT). And few other things. I hope, thins helps. Valeri > > Regards, > Alex > > ___ > CentOS mailing list > CentOS@centos.org > https://lists.centos.org/mailman/listinfo/centos -- Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247 ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Moving from mdadm raid 0 to single disk
On 1/11/22 8:11 PM, Alexandre Leonenko wrote: Hey all, Hopefully a quick question. I'm going to move the filesystem of a raid 0 mdadm to a single disk. The filesystem is just a data drive, can I just dd if=/dev/md0 of=/dev/sdc ? Or should I rather rsync the files directly? I would [partition disk; make new filesystem, mount, then] use rsync. You avoid copying nuisances if there are any on old filesystem. You avoid the need to resize partition on new disk, and expand filesystem. You avoid waste of time copying empty space. You can have different disklabel (it old was MSDOS and you want GPT). And few other things. I hope, thins helps. Valeri Regards, Alex ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos -- Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247 ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Moving from mdadm raid 0 to single disk
On Jan 11, 2022, at 20:11, Alexandre Leonenko wrote: > Hopefully a quick question. I'm going to move the filesystem of a raid 0 > mdadm to a single disk. > The filesystem is just a data drive, can I just dd if=/dev/md0 of=/dev/sdc ? > Or should I rather rsync the files directly? You should use whatever appropriate tools to copy the files directly. The “dd” program is not a backup or data transfer program. It is especially bad for your request. If you did that, you’d be copying every bit on the disk, whether it is used or not. It would get hung up and exit prematurely if it encountered a bad sector (even if the filesystem had it marked in the list of bad blocks). It would create a disk layout that could potentially have significantly worse performance. Better to create a proper partition table and filesystem(s), optimized to the new disk, and use one of the many tools to copy over the actual data. Use the file system’s dump/restore, tar, rsync, etc. There are a small number of cases where “dd” is the right tool. Backups and data transfer is not one of them. -- Jonathan Billings ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
[CentOS] Moving from mdadm raid 0 to single disk
Hey all, Hopefully a quick question. I'm going to move the filesystem of a raid 0 mdadm to a single disk. The filesystem is just a data drive, can I just dd if=/dev/md0 of=/dev/sdc ? Or should I rather rsync the files directly? Regards, Alex ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
