# Xtrabackup of replica - relay log not backed up - Slave failed to initialize relay log **URL:** \ **Category:** Percona XtraBackup\ **Created:** [January 22, 2021, 12:08pm UTC](https://forums.percona.com/t/xtrabackup-of-replica-relay-log-not-backed-up-slave-failed-to-initialize-relay-log/8890 "2021-01-22T12:08:26Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![aviddavid](https://avatars.discourse-cdn.com/v4/letter/a/22d042/32.png) [@aviddavid](https://forums.percona.com/u/aviddavid)\ **Post date:** [January 22, 2021, 12:08pm UTC](https://forums.percona.com/t/xtrabackup-of-replica-relay-log-not-backed-up-slave-failed-to-initialize-relay-log/8890/1 "2021-01-22T12:08:26Z")
Hello. I’m using xtrabackup 8.0.22-15 with MySQL Server 8.0.22 to take full backups from a replica with options `--slave-info` and `--safe-slave-backup`. I’m using binary log file position based replication with MIXED `binlog-format` Using default `relay-log` and `relay-log-index` settings. (uses hostname). Replication fails to start with this error after restoring the backup for a new replica: > ERROR 1872 (HY000): Slave failed to initialize relay log info structure from the repository The corresponding errors from the mysql error log: > [ERROR] [MY-010544] [Repl] Failed to open the relay log ‘./hostname-relay-bin.000002’ (relay\_log\_pos 224567). > > [ERROR] [MY-011059] [Repl] Could not find target log file mentioned in relay log info in the index file ‘./hostname-relay-bin.index’ during relay log initialization. > > [ERROR] [MY-010426] [Repl] Slave: Failed to initialize the master info structure for channel ‘’; its record may still be present in ‘mysql.slave\_master\_info’ table, consider deleting it. Table `mysql.slave_relay_log_info` refers to `hostname-relay-bin.000002` but this file isn’t present because xtrabackup isn’t backing it up (and not restoring it). I can resolve this by running `RESET SLAVE ALL` and then setting up replication again using the `MASTER_LOG_FILE` and `MASTER_LOG_POS` settings from the `xtrabackup_slave_info` file, but: Could this result in some lost transactions? I’m considering a situation that there are some statements in the relay log when xtrabackup runs, and so the MASTER\_LOG\_POS is ahead of what the slave has committed. Since xtrabackup isn’t backing up the relay log and needs a `RESET SLAVE ALL` to start replication after a restore, it seems that any such statements in the relay log might be lost. Does xtrabackup ensure that the replica has fully performed all events in the relay log during backup? Option `--safe-slave-backup` says that it temporary stops the slave SQL thread so perhaps this helps, and so is this option definitely needed to ensure that the replica has an empty relay log? I restore the backup by: 1. Stop MySQL 2. Run xtrabackup with `--prepare` 3. Run xtrabackup with `--copy-back` 4. Start MySQL 5. Run the `CHANGE MASTER` command per `xtrabackup_slave_info` file: `CHANGE MASTER TO MASTER_LOG_FILE='binlog.000002', MASTER_LOG_POS=1234;` 6. Run `START SLAVE;` Example `mysql.slave_relay_log_info` after the steps: > mysql\> select \* from mysql.slave\_relay\_log\_info\G > Number\_of\_lines: 12 > Relay\_log\_name: ./hostname-relay-bin.000002 > Relay\_log\_pos: 224567 > Master\_log\_name: binlog.000002 > Master\_log\_pos: 1234 > Sql\_delay: 0 > Number\_of\_workers: 0 > Id: 1 > Channel\_name: > Privilege\_checks\_username: NULL > Privilege\_checks\_hostname: NULL > Require\_row\_format: 0 > Require\_table\_primary\_key\_check: STREAM ---
**Author:** ![lalit.choudhary](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/lalit.choudhary/32/51_2.png) [@lalit.choudhary](https://forums.percona.com/u/lalit.choudhary)\ **Post date:** [January 22, 2021, 12:51pm UTC](https://forums.percona.com/t/xtrabackup-of-replica-relay-log-not-backed-up-slave-failed-to-initialize-relay-log/8890/2 "2021-01-22T12:51:17Z")
@aviddavid Could you please report this to [https://jira.percona.com/](https://jira.percona.com/) as a bug for the product Percona Xtrabackup and I will check it. ---
**Author:** ![aviddavid](https://avatars.discourse-cdn.com/v4/letter/a/22d042/32.png) [@aviddavid](https://forums.percona.com/u/aviddavid)\ **Post date:** [January 22, 2021, 1:10pm UTC](https://forums.percona.com/t/xtrabackup-of-replica-relay-log-not-backed-up-slave-failed-to-initialize-relay-log/8890/3 "2021-01-22T13:10:33Z")
Thanks @lalit.choudhary - I’ve opened [[PXB-2413] Replication fails after a replica backup is restored - Slave failed to initialize relay log - Percona JIRA](https://jira.percona.com/browse/PXB-2413) ---
**Author:** ![lalit.choudhary](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/lalit.choudhary/32/51_2.png) [@lalit.choudhary](https://forums.percona.com/u/lalit.choudhary)\ **Post date:** [January 27, 2021, 9:11am UTC](https://forums.percona.com/t/xtrabackup-of-replica-relay-log-not-backed-up-slave-failed-to-initialize-relay-log/8890/4 "2021-01-27T09:11:28Z")
@aviddavid Thank you. I verified and updated Jira bug PXB-2413 with a test case. ---
**Author:** ![turnon2003](https://avatars.discourse-cdn.com/v4/letter/t/b487fb/32.png) [@turnon2003](https://forums.percona.com/u/turnon2003)\ **Post date:** [March 27, 2023, 12:07pm UTC](https://forums.percona.com/t/xtrabackup-of-replica-relay-log-not-backed-up-slave-failed-to-initialize-relay-log/8890/6 "2023-03-27T12:07:47Z")
Hi, has this issue been resolved? because i got the same problem in xtrabackup-8.0.32-25-1 and mysql 8.0.32 ---
**Author:** ![lalit.choudhary](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/lalit.choudhary/32/51_2.png) [@lalit.choudhary](https://forums.percona.com/u/lalit.choudhary)\ **Post date:** [March 28, 2023, 5:14am UTC](https://forums.percona.com/t/xtrabackup-of-replica-relay-log-not-backed-up-slave-failed-to-initialize-relay-log/8890/7 "2023-03-28T05:14:44Z")
Hello @turnon2003 [[PXB-2413] Replication fails after a replica backup is restored - Slave failed to initialize relay log - Percona JIRA](https://jira.percona.com/browse/PXB-2413) Is Still Open state. Please Login to JIra, go to PXB-2413 report, and click on “Vote for this issue” as it’s affected you. More Votes will prioritize the issue.