System clock losing several seconds per minute permalink
Note to self. If this happens again, shut the computer down, turn off the power supply and hold the power button down for several seconds to totally drain any voltage. Most interesting thing in the log:
APIC calibration not consistent with PM-Timer: 0ms instead of 100ms APIC delta adjusted to PM-Timer: 1440271 (1022)[Update] adding tsc=unstable to the kernel boot command line in grub sorted the problem.
Creating an encrypted backup on a USB stick permalink
USB sticks are 1) slow to write and 2) wear out. I've previously ruined a stick by creating a LUKS encrypted filesystem on one and then rsync'ing my home directory to it.
My work-around has been to create the filesystem in a Logical Volume on my hard disc and then dd it
However, this doesn't work (anymore?). cryptsetup luksOpen of the USB stick fails:
Jul 26 14:40:57 frodo kernel: device-mapper: table: 254:29: crypt: Device size is not multiple of sector_size feature (-EINVAL) Jul 26 14:40:57 frodo kernel: device-mapper: ioctl: error adding target to tableThis can be further worked around by mapping a loop filesystem of the correct size onto the LV:
losetup --show --sizelimit 123730388992 -f /dev/vg1/templv
## what is the size of the USB stick? lsblk -b /dev/sdd # NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS # sdd 8:48 1 123730388992 0 disk ## create LV of that size lvcreate -n temp -L123730388992b vg1 ## but it's too big lsblk -b /dev/sdd /dev/mapper/vg1-temp # NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS # sdd 8:48 1 123730388992 0 disk # vg1-temp 254:15 0 123731968000 0 lvm ## so set up a loop device losetup --show --sizelimit 123730388992 -f /dev/vg1/temp cryptsetup luksFormat /dev/loop0 cryptsetup --verbose --debug luksDump /dev/loop0 | grep "Device size" # Device size 123730388992, offset 16777216. cryptsetup luksOpen /dev/loop0 enc-usb mkfs.f2fs /dev/mapper/enc-usb mount /dev/mapper/enc-usb /mnt/usb # now rsync the files to /mnt/usb umount /mnt/usb/ cryptsetup luksClose enc-usb losetup -d /dev/loop0 # copy to USB dd if=/dev/vg1/temp of=/dev/sdd bs=4M status=progress