… apps are mostly read traffic, so a single primary can delegate the read workload across several replicas, and the write workload is still… the app gets large enough, no matter how large the read-to-write ratio is. What are some workarounds? Here are a few… can’t be used for serving reads, only for disaster recovery. That’s costly. Shard. Write workload is the single most legitimate…
Comment: 5.0.83-build17 Percona binaries
August 4, 2009 By 19 Comments
… makes thoses drives inoperable with write heavy databases, is that when the writes are “blocking”, the pending reads from the drive are also… until the writes are completed. This checkpointing may occur more or less often, depending on the log size and the write ratio, but in my case it happens ~10 times a day (70% writes / 30% reads) This is really a…
Comment: Benchmarks of new innodb_flush_neighbor_pages
July 3, 2012 By 8 Comments
… problem. Use more eager writing in parellel instead of lazy writng to disk and set lower dirty ratio to start flushing, terminate worker flushing threads at a faster rate. There should be better ways of allowing read and writes… request so flushing would not have to wait on stalled read/writes. I believe the Deadline scheduler is not the default schedualer…
Comment: Evaluating IO subsystem performance for MySQL Needs
March 6, 2008 By 23 Comments
… lookups) per second across a few mysql servers, with 70% read / 30% write ratio – without using O_DIRECT (can’t because its broken… random read I/O and 10 MB a sec of random write I/O on 3 effective spindles for writes and 6 for reads…
Post: Using Multiple Key Caches for MyISAM Scalability
November 26, 2008 By 8 Comments
… KeyCache. Table Locks are not the issue for Read Only workload and write intensive workloads can be dealt with by using with… t.table_name in (‘a’,'b’)) s_ratio, (rows_read+rows_changed)/(select sum(rows_read+rows_changed) from information_schema.table_statistics where table_schema=’test’ and t.table_name in (‘a’,'b’)) u_ratio…
Post: Different flavors of InnoDB flushing
January 13, 2011 By 9 Comments
…in order to test different memory/dataset size ratios. But why is it important, and how does…details. Internally, InnoDB uses two lists for flushing (writing pages from the Innodb buffer pool memory to … really impressed at what a stable level of reads and writes per second the Virident tachIOn card …
Post: Heikki Tuuri answers to Innodb questions, Part II
November 4, 2007 By 13 Comments
… which is being requested via read-ahead. Q27 If my workload has a hi amount of concurrent writes to about 6 tables… disk controller write-back cache does the same thing. PZ: First Indeed writes are slower with Flash disks compared to Reads because Flash… will be running (monitoring, backup, cron, syslog, etc). But the ratio of RAM used for these non-mysql processes drops rapidly…
Post: Death match! EBS versus SSD price, performance, and QoS
February 21, 2011 By 55 Comments
… math to get something approximating the real device utilization, but reads and writes aren’t broken out, so you can’t actually…. Sub-millisecond latencies to disk, pretty much consistently, for reads and writes, is very good. I’m averaging across large periods of…-performance ratio for the database as compared to a handful of SSDs (or traditional disks, for that matter, which would show writes…
Post: Living with backups
November 6, 2008 By 28 Comments
… disks to read or write whatever comes so that your favorite website can still show up in the browser. Moreover, reads sent from… by random “garbage” for no good reason. Since the hit ratio becomes worse as the cache is being filled with random… – mysql | ssh backup@storage-host /root/backup-tools/write_backup.sh This will read /mnt/snapshot/mysql directory at 15000000 bytes/s…
Post: Modeling MySQL Capacity by Measuring Resource Consumptions
March 8, 2011 By 1 Comment
… running Innodb with MySQL we can use Innodb_data_reads , Innodb_data_writes, Innodb_os_log_fsyncs for your disk IO estimation…) but it also can be row level locks, etc. The ratio between Wait Time and CPU time is very helpful to… system is”. If it system is already have low wait ratio increasing amount of memory for example is unlikely to help…
