I've run across this problem before - it seems like GNU tar interprets changes in the link count as changes to the file, so if the file gets compacted mid-backup it freaks out even if the file contents are unchanged. I worked around it by just using bsdtar instead.
On Thu, May 24, 2018 at 6:08 AM, Nitan Kainth <nitankai...@gmail.com> wrote: > Jeff, > > Shouldn't Snapshot get consistent state of sstables? -tmp file shouldn't > impact backup operation right? > > > Regards, > Nitan K. > Cassandra and Oracle Architect/SME > Datastax Certified Cassandra expert > Oracle 10g Certified > > On Wed, May 23, 2018 at 6:26 PM, Jeff Jirsa <jji...@gmail.com> wrote: > >> In versions before 3.0, sstables were written with a -tmp filename and >> copied/moved to the final filename when complete. This changes in 3.0 - we >> write into the file with the final name, and have a journal/log to let uss >> know when it's done/final/live. >> >> Therefore, you can no longer just watch for a -Data.db file to be created >> and uploaded - you have to watch the log to make sure it's not being >> written. >> >> >> On Wed, May 23, 2018 at 2:18 PM, Max C. <mc_cassan...@core43.com> wrote: >> >>> Hi Everyone, >>> >>> We’ve noticed a few times in the last few weeks that when we’re doing >>> backups, tar has complained with messages like this: >>> >>> tar: /var/lib/cassandra/data/mars/test_instances_by_test_id-6a944 >>> 0a04cc111e8878675f1041d7e1c/snapshots/backup_20180523_024502/mb-63-big-Data.db: >>> file changed as we read it >>> >>> Any idea what might be causing this? >>> >>> We’re running Cassandra 3.0.8 on RHEL 7. Here’s rough pseudocode of our >>> backup process: >>> >>> <cronjob set to fire same script at same time on all nodes> >>> SNAPSHOT_NAME=backup_YYYMMDD_HHMMSS >>> nodetool snapshot -t $SNAPSHOT_NAME >>> >>> for each keyspace >>> - dump schema to “schema.cql" >>> - tar -czf /file_server/backup_$HOSTNAME_$KEYSPACE_YYYYMMDD_HHMMSS.tgz >>> schema.cql /var/lib/cassandra/data/$KEYSPACE/*/snapshots/$SNAPSHOT_NAME >>> >>> nodetool clearsnapshot -t $SNAPSHOT_NAME >>> >>> Thanks. >>> >>> - Max >>> --------------------------------------------------------------------- >>> To unsubscribe, e-mail: user-unsubscr...@cassandra.apache.org >>> For additional commands, e-mail: user-h...@cassandra.apache.org >>> >>> >> >
