On 03/02/2017 08:53 PM, Warren Young wrote: > On Mar 2, 2017, at 6:36 PM, Robert Moskowitz <rgm at htt-consult.com> wrote: >> I want to image the drive at various 'checkpoints' so I can go back and redo from a particular point… >> what dd params work? >> >> dd if=/dev/sdb of=os.img bs=1M count=3210 > That looks plausible. (I haven’t verified your count parameter exactly.) > > However, I wonder why you’re trying to reinvent snapshots, a technology now built into several advanced filesystems, such as btrfs and ZFS? > > https://en.wikipedia.org/wiki/Btrfs#Subvolumes_and_snapshots > > btrfs is built into CentOS 7. While there have been some highly-publicized bugs in btrfs, they only affect the RAID-5/6 features. You don’t need that here, so you should be fine with btrfs. > > And if you really distrust btrfs, ZFS is easy enough to integrate into CentOS on-site. > > And if *that* is also out of the question, you have LVM2 snapshots: > > http://tldp.org/HOWTO/LVM-HOWTO/snapshots_backup.html > > Why reinvent the wheel? This is Centos7-armv7. Not all the tools are there. I keep getting surprises in some rpm not in the repo, but if I dig I will find it (but php-imap is NOT built yet and that I need). The base image is a dd, and you start with something like: xzcat CentOS-Userland-7-armv7hl-Minimal-1611-CubieTruck.img.xz | sudo dd of=/dev/sdb bs=4M; sync btw, this reports: 0+354250 records in 0+354250 records out 3221225472 bytes (3.2 GB, 3.0 GiB) copied, 120.656 s, 26.7 MB/s Then you boot up (connected via the JART with a USB/TTL for a serial console). I want a drive image, and that is easy to do. I disconnect my drive from the CubieTruck, stick it into a USB/sata adapter, and I can image the whole drive. For just a development and snapshotting project, dd (and xzcat) do the job, and really what the Fedora-arm and Centos-arm teams have been doing. I actually did this 2+ years creating Redsleeve6 images, but can't find any of my notes. :(