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From Nitan Kainth <nitankai...@gmail.com>
Subject Re: Snapshot SSTable modified??
Date Thu, 24 May 2018 13:08:00 GMT
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 <jjirsa@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_cassandra@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
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>>
>

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