Hello list, I subscribed a few minutes ago, and I've got a question already :-) I've done some searching and research on my problem, but haven't had any success yet. So I thought I'd pose it to this list, in the hope of finding some tips for solving it. I have an HP server running RHEL 5.7. It contains four hard disks, in two hardware RAID-1 groups. The first RAID-1 contains the operating system and utilities; the second is slated for compressed snapshot dumps of the first. There's nothing particularly freaky about the configuration of the machine, as far as I can tell. I wrote a script which does the following: # lvcreate -pr -L 2G -s -n LogVol00-snapshot /dev/VolGroup00/LogVol00 # dd bs=8k if=/dev/VolGroup00/LogVol00-snapshot | gzip -3 -c > /backup/LogVol00.img.gz After this completes, I verify the dump by comparing the output of: # md5sum /dev/VolGroup00/LogVol00-snapshot with # gunzip -c /backup/LogVol00.img.gz | md5sum This method seems to have been repeatedly successful on four other servers of similar hardware configuration. I am running the same script on all of them. The other machines have a larger logical volume (500Gb vs this machine, 260G) but the PVs are all the same (whole disk except the /boot partition). However, on this machine, I got an md5sum mismatch. Seeking the source of the weirdness, I ran a second dd from the same snapshot: # dd bs=8k if=/dev/VolGroup00/LogVol00-snapshot | gzip -3 -c > /backup/LogVol00-again.img.gz .. and md5sum gave me a third, different, result. It seems as if the data read from the snapshot is changing. Do I have a conceptual misunderstanding of what I'm doing? Can anyone suggest things for me to look at, verify, or test? Am I missing something blindingly obvious here? :-) Any and all suggestions and comments welcomed! Cheers and beers, Nick _______________________________________________ linux-lvm mailing list linux-lvm@redhat.com https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
