core-agent-linux/init/setup-rwdev.sh
Marek Marczykowski-Górecki 1781568d08
Speed up initial /rw setup
On first VM's boot, setup-rwdev.sh script create filesystem on
/dev/xvdb. But it does so only after checking if /dev/xvdb is really
empty, by comparing it to /dev/zero. Speed up reads from /dev/zero bu
using larger blocks (default of head - 8k, instead of explicit 512).
This speed up the check over 5 times.
2018-02-27 05:12:44 +01:00

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#!/bin/sh
set -e
dev=/dev/xvdb
if [ -e "$dev" ] ; then
# The private /dev/xvdb device is present.
# check if private.img (xvdb) is empty - all zeros
private_size_512=$(blockdev --getsz "$dev")
if head -c $(( private_size_512 * 512 )) /dev/zero | diff "$dev" - >/dev/null; then
# the device is empty, create filesystem
echo "Virgin boot of the VM: creating private.img filesystem on $dev" >&2
if ! content=$(mkfs.ext4 -m 0 -q "$dev" 2>&1) ; then
echo "Virgin boot of the VM: creation of private.img on $dev failed:" >&2
echo "$content" >&2
echo "Virgin boot of the VM: aborting" >&2
exit 1
fi
if ! content=$(tune2fs -m 0 "$dev" 2>&1) ; then
echo "Virgin boot of the VM: marking free space on $dev as usable failed:" >&2
echo "$content" >&2
echo "Virgin boot of the VM: aborting" >&2
exit 1
fi
fi
echo "Private device management: checking $dev" >&2
if content=$(fsck.ext4 -p "$dev" 2>&1) ; then
echo "Private device management: fsck.ext4 of $dev succeeded" >&2
else
echo "Private device management: fsck.ext4 $dev failed:" >&2
echo "$content" >&2
fi
fi