Failing to create incremental backups

MySQL & MariaDB Percona XtraBackup
1

So, we are having a couple of servers with old MySQL5.5 and XtraBackup 2.4. We are trying to back up the databases to an NFS mounted file share, but the incremental backups are all “full-backuped”.

Full backup is created successfully like this:

xtrabackup --backup --compress --compress-threads=4 --target-dir=/backupnfs/xtrabackup/full1 --extra-lsndir=/var/log/xtrabackup_lsn

Then an attempt to create an incremental backup like this fails, resulting in another full backup:

xtrabackup --backup --compress --compress-threads=4 --target-dir=/backupnfs/xtrabackup/part_f1_p1 --incremental-base-dir=/backupnfs/xtrabackup/full1 --extra-lsndir=/var/log/xtrabackup_lsn

For the record, all tables are InnoDB tables.

What are we doing wrong?

Thanks in advance for your help.

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@gantonjo , The parameter “extra-lsndir” is unusual. Can you please try your process without that parameter? I just training a client and their team on incremental backups 2 days ago and we don’t use that parameter and all works great. Might I also suggest adding --parallel=4

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Hi, @matthewb.

Thanks for your advice, but extra-lsndir is not the reason for the problem, we added it as part of our troubleshooting. It holds the LSN info from the last run, hence should be simplifying the whole process, as far as I can tell.

I cannot see why parallel=4 would solve the problem, but will give it a try.

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Hi @gantonjo, I never said that --parallel would solve the problem, nor did I say extra-lsndir would solve it either. I was giving 2 suggestions based on personal experience for you to try and see if either helped the situation. In our formal training sessions, we don’t use extra-lsndir and incrementals work flawlessly. That’s the only difference between your command and what we use in our classes.

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Hi @gantonjo .

Can you please share how you are validating the second backup is a full backup?

Can you please share the logs from both full and incremental backup?
Also, can you share the output of xtrabackup_info and xtrabackup_checkpoints from incremental backup?

And since you are using a NFS, make sure you read https://www.percona.com/doc/percona-xtrabackup/LATEST/using_xtrabackup/configuring.html#system-configuration-and-nfs-volumes . In other words, try to run sync command in between backups to be in the safe side.

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