… the original node where the transaction is committed) Galera prevents writing conflicts to these pending transactions while they are inflight in… around it with by fsyncing to memory (Battery or capacitor-backed write cache), etc., but the principle is basically the same. If… means more latency waiting for a write to go through, and possibly some poor user experience. batch writes Instead of updating global counters…
Post: Follow these basics when migrating to Percona XtraDB Cluster for MySQL
May 1, 2013 By 10 Comments
… consistent within the cluster. Also, at the time of this writing, from async stream, MyISAM is not being replicated at all… turning the feature back on when you switch to the new cluster especially if you are planning to write on multiple nodes… you are consistently running overnight reporting jobs and getting them through the replication stream expect some replication lag. This is because…
Post: Percona Server 5.5.30-30.2 rerelease fixes non-restart issue
April 24, 2013 By Leave a Comment
… Six at Percona Live MySQL Conference and Expo for walking through this. — More info on Percona Server 5.5.30-30… contention on log_sys->mutex in write-intensive workloads. Bug fixed #1163439 (Alexey Kopytov). Ported back from the upstream MySQL 5.6…
Comment: Disaster: LVM Performance in Snapshot Mode
February 9, 2009 By 55 Comments
…. Write percentage controls the ratio of reads/writes done by each thread. My setup was 6 SAS 10K drives with 512MB write-back cache… competing reads/writes. I believe that ext3 is taking an exclusive rwlock on each write and doesn’t release it through the whole… should be a very fast write under normal circumstances (write-back cache) turns into a read and a write while holding the exclusive rwlock…
Post: Testing the Group Commit Fix
July 13, 2011 By 13 Comments
…, automatically switching from write-back to write-through cache mode. We benchmarked the systems with sysbench multi-table and oltp read-write workload. All scripts… and sync_binlog=1 options are set and write-back cache is not enabled. Write-back cache is must-have for an environment demanding…
Post: Looking for RAID Controller without Battery Learning problems ?
January 5, 2012 By 11 Comments
…setting : Disabled MaxIQ cache setting : Disabled Write-cache mode : Enabled (write-back) Write-cache setting : Enabled (write-back) when protected by battery/ZMM Partitioned :…write-back) when protected by battery/ZMM”, which is setting you want to have as you want to ensure it goes to write through…
Post: The relationship between Innodb Log checkpointing and dirty Buffer pool pages
February 17, 2012 By 10 Comments
…on these numbers, we can determine how many bytes back in the transaction log our oldest … dirty pages get flushed) has a look through the dirty pages in the buffer pool…writes to the transaction log if you set this too high. innodb_write_io_threads: Controls how many threads will have writes…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
…. I can also get information about the all-important battery-backed write cache, how it’s configured and what its status is… This output is very useful when writing the report to the client. Now I go through it line by line looking for… not be easy. So this consultant looked through things, spent about 2 hours, and came back to the client with “there’s…
Post: Aligning IO on a hard disk RAID – the Benchmarks
June 9, 2011 By 13 Comments
… to write-through (WT), though in fact for every benchmark I have repeated it with (a) write-through and (b) write-back to see if write-back cache… run twice – first with RAID controller cache set to Write-Through and then to Write-Back. 1. Baseline – misalignment on the partition table, no…
Post: SHOW INNODB STATUS walk through
July 17, 2006 By 40 Comments
… me to publish a walk through SHOW INNODB STATUS output, showing what you can…3: len 10; hex 61202020202020202020; asc a ;; *** WE ROLL BACK TRANSACTION (2) For last deadlock Innodb shows …commit=2 log writes are done to OS cache, and being sequential writes these logs writes are pretty fast. …
