…write to a single disk because of the alignment to a stripe unit. In the second example however every other page spans two disks…number of disks and the size of a stripe element set the stripe width size. In case of RAID1 and JBOD there’s no striping, with RAID0 number of…
Post: The relationship between Innodb Log checkpointing and dirty Buffer pool pages
February 17, 2012 By 10 Comments
…of the total number of bytes in all the transaction logs, but I’m unsure if that’s always the…the transaction log if you set this too high. innodb_write_io_threads: Controls how many threads will have writes in progress to the disk…
Post: Aligning IO on a hard disk RAID – the Benchmarks
June 9, 2011 By 13 Comments
…the goal was to compare performance with different IO alignment, not different MySQL configurations, I didn’t try out different MySQL…the random read (and write) benchmark with 8 threads and total size of 256G. While the number of operations per second was slightly lower, the…
Post: Evaluating IO subsystem performance for MySQL Needs
March 5, 2008 By 23 Comments
…Number of random requests for random IO: 1000000 Read/Write ratio for combined random IO test: 1.50 Calling fsync() at the end of…total time: 60.0001s total number of events: 773835 total time taken by…
Post: Virtualization and IO Modes = Extra Complexity
March 21, 2011 By 12 Comments
…total file size Block size 16Kb Number of random requests for random IO: 10000000 Read/Write…the test with following options: Number of threads: 1 Extra file open flags: 16384 1 files, 1Mb each 1Mb total…total time: 60.0019s total number of events: 33900 total time taken by…
Post: Death match! EBS versus SSD price, performance, and QoS
February 21, 2011 By 55 Comments
…writes, and then we have the percent of time the device was busy, and the average number of requests in progress at the time the…of the disks. We’re trying to read a total of 3.7 MB/s and write…
Post: Modeling MySQL Capacity by Measuring Resource Consumptions
March 8, 2011 By 1 Comment
…writes, Innodb_os_log_fsyncs for your disk IO estimation. When you can divide it per number of…of user time and 53.03 system time consumed by the process. Collecting these at regular intervals and correlating to number of…
Post: 10+ Ways to Crash or Overload MySQL
November 13, 2007 By 20 Comments
…MySQL account and they have been normally treated very quickly by MySQL. The moment you give someone access to MySQL Server, all MySQL…by keeping myisam_sort_buffer_size low, but then performance would suffer. Prepared Statements Number – Happily now there is a limit on total number of…
Post: Is disk Everything for MySQL Performance ?
April 25, 2008 By 7 Comments
…disks they have instead of how many systems they have” on MySQL UC2008 Scalability Panel ? Indeed disks MAY be the…the limit rather than number of IOs it can handle. Imagine for example data archive storage. On BoardReader for example we’re limited by…
Post: Shard-Query EC2 images available
May 11, 2011 By 2 Comments
…the du utility: InnoDB file size on disk: 42GB (with indexes) # du -sh * 203M ibdata1 128M ib_logfile0 128M ib_logfile1 988K mysql…the desired number of EC2 instances using on of the the AMI images. You should spin a number of…write…
