…take on server. There is no comparable variables of how many user variables are allocated (and how much memory they …127499384 Dictionary cache 512619219 (509995888 + 2623331) File system 294352 (82672 + 211680) Lock system 318875832 (318747272 + 128560) Recovery system 0 (0 + 0) Threads 425080 (…
Post: ext4 vs xfs on SSD
March 15, 2012 By 23 Comments
As ext4 is a standard de facto filesystem for many modern Linux system, I am getting a lot of question if this… in 100 do cd /mnt/stec sysbench –test=fileio –file-num=1 –file-total-size=${size}G prepare sync echo 3 > /proc…=$numthreads –rand-init=on –file-num=1 –file-extra-flags=direct –file-fsync-freq=0 –file-io-mode=sync –file-block-size=16384 –report-interval…
Comment: Btw xtrabackup is not only backup..
March 5, 2012 By 12 Comments
…all. It’s also directed toward the fact that many people have asked this same question in forums …documented bugs in the Percona docs that have been filed on this subject and they keep getting re-assigned…is that I’m here to design relational database systems for software and I don’t have time to…
Post: Make your file system error resilient
August 24, 2011 By 8 Comments
… systems like XFS will not continue if consistency problems are discovered. So how can you check what error behavior mode your file system… filesystem data structures which may be affects one file will take out whole file system. I do not think these concerns are valid… to automatic file system check on startup which is normally done once per so many mounts or so many days. Large partitions with many files can…
Post: MySQL File System Fragmentation Benchmarks
March 21, 2008 By 28 Comments
Few days ago I wrote about testing writing to many files and seeing how this affects sequential read performance. I was … times. This could be because ext3 does not like so many files in directory or because random updates to 10000 distinct pages… things we can learn from these results – Concurrent growth of many tables causes data fragmentation and affects table scan performance nadly…
Post: How innodb_open_files affects performance
November 18, 2009 By 4 Comments
… similar variable – innodb_open_files which defines how many files Innodb will keep open while working in innodb_file_per_table mode. Unlike MyISAM Innodb does not have to keep open file… open files was, which is not surprising as logical operation of opening file is rather fast on local file system – one can open/close file…
Post: Working with many files and file system fragmentation
March 18, 2008 By 11 Comments
… related) we did a test – creating 100 files writing 4K in the random file for some time and when checking the read… performance difference was huge – we could read single file at 80MB/sec while fragmented files only deliver about 2MB/sec – this is… does not do very good job preventing file fragmentation for large amount of growing files. It would be interesting to see how…
Post: Aligning IO on a hard disk RAID – the Theory
June 9, 2011 By 15 Comments
… do anything to align InnoDB pages – file system takes care of it (assuming you configure the file system correctly). I would however mention couple…. File system File system plays very important role here – it maps files logical address to physical address (at a certain level) so when writing a file, file system… using defaults (you would get the same on RHEL5 and many other systems): db1# fdisk -ul Disk /dev/sda: 1197.9 GB…
Post: Content delivery system design mistakes
February 11, 2007 By 9 Comments
… related to LAMP in general) of system which does quite a bit of content delivery, serving file downloads and images – something a… from memory or serving large files (in which case read-ahead helps) but if you’re serving many millions of thumbnails it… content it gets from PHP script which means many megabytes for large files. Partial file sending happily was added in lighttpd 1.5…
Post: Rendundant Array of Inexpensive Servers
August 21, 2008 By 15 Comments
… which is enough to maintain level of availability needed by many small systems. In fact they typically would have order of magnitude… classic database/storage systems. Few systems are design with so much error detection and automated handling in mind as Google File System. In particular…
