opendev/system-config
Code Issues Proposed changes

Better swap alignment

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We ran into this when fixing the zuul02 swap partition. Essentially
parted complained that our alignments weren't optimal. After some
googling the Internet said that using multiples of 8 tends to be safe.
We shifted the offset from 1MB to 8MB to start the partition and the
warnings went away.

Add this change into make_swap.sh to automate this for future servers.

Change-Id: Iad3ef40cf2c1e064482d49bd722c3de4354ec74d
This commit is contained in:
Clark Boylan 2021-05-17 15:03:05 -07:00
parent 51e3976273
commit 0d7c02f132
1 changed files with 4 additions and 2 deletions
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6
launch/make_swap.sh
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@ -24,8 +24,10 @@ if [ `grep SwapTotal /proc/meminfo | awk '{ print $2; }'` -eq 0 ]; then
SWAPFILE=/swapfile
MEMKB=`grep MemTotal /proc/meminfo | awk '{print $2; }'`
# Use the nearest power of two in MB as the swap size.
# We also shift by 8MB to start the partitions as apparently
# parted and linux prefer things aligned on multiples of 8.
# This ensures that the partitions below are aligned properly.
MEM=`python3 -c "import math ; print(min(2**int(round(math.log($MEMKB/1024, 2))),8192))"`
MEM=`python3 -c "import math ; print(min(2**int(round(math.log($MEMKB/1024, 2))),8192) + 8)"`
# Avoid using config drive device for swap
if [ -n "$DEV" ] && ! blkid | grep $DEV | grep TYPE ; then
@ -37,7 +39,7 @@ if [ `grep SwapTotal /proc/meminfo | awk '{ print $2; }'` -eq 0 ]; then
parted ${DEV} --script -- \
mklabel msdos \
mkpart primary linux-swap 1 ${MEM} \
mkpart primary linux-swap 8 ${MEM} \
mkpart primary ext2 ${MEM} -1
sync
# We are only interested in scanning $DEV, not all block devices