ChrisYx511

I've modified @Tomr's snapshot with retention policy script to merge in @catapultam_habeo's original snapshot pruning method in order to improve the reliability of snapsot pruning. I've changed it back to a number of snapshots being retained instead of retention minutes. I found that going off minutes was fairly unreliable and often failed to auto-prune. EDIT: Forgot I also added back the exclusion list instead of an inclusion list. Instructions for shadow copy remains unchanged: Here's the script: #!/bin/bash #description=This script implements incremental snapshots on btrfs array drives. #arrayStarted=true ## Credits # catapultam_habeo - Initial script # Tomr - Modified version with SNAPSHOT_TYPE retention policy #If you change the type you'll have to delete the old snapshots manually #valid values are: hourly, daily, weekly, monthly SNAPSHOT_TYPE=hourly #How many snapshots should be kept. MAX_SNAPS= #Name of the shares to exclude, can be comma separated like "medias,valuables" EXCLUDE= #name of the snapshot folder and delimeter. Do not change. #https://www.samba.org/samba/docs/current/man-html/vfs_shadow_copy2.8.html SNAPSHOT_DELIMETER="_UTC_" SNAPSHOT_FORMAT="$(TZ=UTC date +${SNAPSHOT_TYPE}${SNAPSHOT_DELIMETER}%Y.%m.%d-%H.%M.%S)" shopt -s nullglob #make empty directories not freak out is_btrfs_subvolume() { local dir=$1 [ "$(stat -f --format="%T" "$dir")" == "btrfs" ] || return 1 inode="$(stat --format="%i" "$dir")" case "$inode" in 2|256) return 0;; *) return 1;; esac } #ADJUST MAX_SNAPS to prevent off-by-1 MAX_SNAPS=$((MAX_SNAPS+1)) #Tokenize exclude list declare -A excludes for token in ${EXCLUDE//,/ }; do excludes[$token]=1 done #iterate over all disks on array for disk in /mnt/disk*[0-9]* ; do #examine disk for btrfs-formatting (MOSTLY UNTESTED) if is_btrfs_subvolume $disk ; then #iterate over shares present on disk for share in ${disk}/* ; do declare baseShare=$(basename $share) #test for exclusion if [ -n "${excludes[$baseShare]}" ]; then echo "$share is on the exclusion list. Skipping..." else #check for .snapshots directory prior to generating snapshot #only before we make the actual snapshot #so we don't create empty folders if [ -d "$disk" ]; then if [ ! -d "$disk/.snapshots/$SNAPSHOT_FORMAT/" ] ; then #echo "new" mkdir -v -p $disk/.snapshots/$SNAPSHOT_FORMAT fi fi #echo "Examining $share on $disk" is_btrfs_subvolume $share if [ ! "$?" -eq 0 ]; then echo "$share is likely not a subvolume" mv -v ${share} ${share}_TEMP btrfs subvolume create $share cp -avT --reflink=always ${share}_TEMP $share rm -vrf ${share}_TEMP fi #make new snap btrfs subvolume snap -r ${share} $disk/.snapshots/${SNAPSHOT_FORMAT}/$baseShare fi done #find old snaps echo "Found $(find ${disk}/.snapshots/${SNAPSHOT_TYPE}${SNAPSHOT_DELIMETER}*/ -maxdepth 0 -mindepth 0 | sort -nr | tail -n +$MAX_SNAPS | wc -l) old snaps" for snap in $(find ${disk}/.snapshots/${SNAPSHOT_TYPE}${SNAPSHOT_DELIMETER}*/ -maxdepth 0 -mindepth 0 | sort -nr | tail -n +$MAX_SNAPS); do for share_snap in ${snap}/*; do btrfs subvolume delete $share_snap done rmdir $snap --ignore-fail-on-non-empty done fi done Hope it's useful!

Ok so that means that it shouldn't affect parity at all since it's just in the filesystem right? It's just as if you deleted a bunch of files and created new ones. Thank you!

Hi, I have a question concerning parity and BTRFS snapshots. Let’s say all my data disks are BTRFS, and I snapshotted every single one. Now suppose something catastrophic happened and I need to rollback the snapshot on all the disks. Wouldn’t the parity be out of sync and if so, how would I fix that? Thank you so much!