… graph actually doesn’t show a ratio — it just shows the absolute values of the reads, writes, and creates per second, stacked on top of each other. The person was mentally comparing them and creating a ratio from them. But there’s no ratio on the graph itself: Regardless of that, some systems ought to have more reads than writes…
Post: Virtualization and IO Modes = Extra Complexity
March 21, 2011 By 12 Comments
… size 16Kb Number of random requests for random IO: 10000000 Read/Write ratio for combined random IO test: 1.50 Periodic FSYNC enabled… size 16Kb Number of random requests for random IO: 10000000 Read/Write ratio for combined random IO test: 1.50 Periodic FSYNC enabled… Doing random write test Threads started! Time limit exceeded, exiting… Done. Operations performed: 0 Read, 33900 Write, 339 Other = 34239 Total Read 0b Written…
Post: Evaluating IO subsystem performance for MySQL Needs
March 5, 2008 By 23 Comments
… usually look for MySQL is performance in random reads and random writes. Sequential reads and writes are rarely the problem for OLTP workloads, so… size 16Kb Number of random requests for random IO: 1000000 Read/Write ratio for combined random IO test: 1.50 Calling fsync() at… Doing random read test Threads started! Time limit exceeded, exiting… Done. Operations performed: 773835 Read, 0 Write, 0 Other = 773835 Total Read 11.808Gb…
Comment: 5.0.83-build17 Percona binaries
August 4, 2009 By 19 Comments
… very write heavy scenarios I’d agree. It does however give a massive boost in responsiveness over the 7200rpm drives for reads…. I have noticed the write delays on large data writes such as repairs, but with a mixed read-write load it happens less frequently… only in the following scenarios: – A database with a read write ratio below 80% read / 20% write. – Slave servers to maximise throughput without having to…
Comment: Percona XtraDB Cluster Feature 2: Multi-Master replication
January 25, 2012 By 16 Comments
Vadim, I use Percona Server 5.1 in a Two Master No Slave MMM configuration. The read write ratio of our application is 90/10. How do I distribute the reads and writes in a 3 Node Percona XtraDB Cluster? My method today is via MySQL MMM of Read & Write Roles virtual IP through a JDBC connection.
Comment: Group commit and real fsync
July 3, 2008 By 9 Comments
… size 16Kb Number of random requests for random IO: 10000 Read/Write ratio for combined random IO test: 1.50 Periodic FSYNC enabled…/O mode Doing random write test Threads started! Done. Operations performed: 0 Read, 10000 Write, 10000 Other = 20000 Total Read 0b Written 156.25Mb…
Comment: Adjusting Innodb for Memory resident workload
March 26, 2009 By 11 Comments
… where databases isn’t in terabytes, but has very high read/write ratio, so very heavy random I/O. Ability to make a…
Post: What MySQL buffer cache hit rate should you target
June 29, 2006 By 5 Comments
…. First thing which needs to be understand is – cache hit ratio can be computed differently for different engines. For example for… busy were drives with concurrent requests, how random were these reads/writes, how good was OS or SAN cache hit rate – something… to see how many reads and writes are done and where do they come from (log writes, data/index reads etc) but you would…
Post: SHOW INNODB STATUS walk through
July 17, 2006 By 40 Comments
… can see “OS Waits” for mutexes, as well as for read-write locks. For these information both for exclusive locks and for… 17909940 OS file reads, 22088963 OS file writes, 1743764 OS fsyncs 0.20 reads/s, 16384 avg bytes/read, 5.00 writes/s, 0.80… recs were merged and how many merges did it took. Ratio of number of merges to number of inserts is pretty…
Comment: Disaster: LVM Performance in Snapshot Mode
February 9, 2009 By 55 Comments
… threads. Write percentage controls the ratio of reads/writes done by each thread. My setup was 6 SAS 10K drives with 512MB write-back cache… when it comes to competing reads/writes. I believe that ext3 is taking an exclusive rwlock on each write and doesn’t release… COW operation and so it chokes readers once again. Bigger write ratio has even a more drastic effect on ext3 + snapshot performance…
