… the file to a new name, and then truncates the original file. no copytruncate – Uses the rename() system call to move the file to a new name, and then expects the daemon to be signaled to reopen its log file… truncate operation. This problem is particularly evident when using the ext3 file system (instead of xfs). Use FLUSH LOGS instead of sending SIGHUP…
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… note when error is discovered during the operation EXT3, EXT4 filesystem will force file system check on the next startup which is handy… file will take out whole file system. I do not think these concerns are valid. First with recent Linux versions and quality hardware EXT3…
Post: Beware: ext3 and sync-binlog do not play well together
January 21, 2009 By 19 Comments
… performance when sync-binlog=1 is enabled, even though the system with RAID and BBU were expected to have much better… but results were basically the same. Using XFS instead of EXT3 gives expected results – we get 2350 transactions/sec with sync… to see if EXT3 can be fixed in this regard as it is by far the most common file system for Linux. It…
Post: MySQL File System Fragmentation Benchmarks
March 21, 2008 By 28 Comments
… dropped 20 times. This could be because ext3 does not like so many files in directory or because random updates to 10000… performance for 10000 tables would be close. Innodb with innodb_file_per_table=1 had the following results: [root@DB10 ~]# for… is close, the difference is perhaps explained by the fact files needed to be constantly extended (meta data updates) and reopened…
Post: Binary log file size matters (sometimes)
May 24, 2012 By 6 Comments
… was not allowed to run pmp or oprofile on that system due to potential performance impact. However, somehow I have noticed… and if your file system is slow at deleting files (both customers systems ran on ext3, which can be very slow deleting large files), then write…: we have reduced the size of binary log file from default 1GB (some systems have it set to 100MB in their default…
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… file at 80MB/sec while fragmented files only deliver about 2MB/sec – this is a massive difference. The test was done on EXT3 and it looks like it does not do very good job preventing file fragmentation for large amount of growing files. It…
Comment: Big Iron for tests anyone ?
March 21, 2008 By 10 Comments
… in-house apps include testing MySQL with a variety of file systems (ext3, jfs, xfs), a variety of storage engines (MySQL 5.0…
Post: Slow DROP TABLE
June 16, 2009 By 21 Comments
… is a known fact that ext3 is not the most efficient file system out there and for example file removals can be painfully slow… is when the slow file removal on the ext3 file system starts to be a pain. Deleting a 10GB file can take a few seconds… seems to be changing the file system. To XFS for example, which handles file removals much more efficiently: EXT3 mysql> drop table large_table…
Comment: Disaster: LVM Performance in Snapshot Mode
February 9, 2009 By 55 Comments
…) and pointer-based block-map technologies of the log structured file systems (WAFL, ZFS). With log structured filesystems you get snapshots practically… or without snapshot. Now let’s look at ext3 with the same size file – [root@udbqa006.sf2p /home/pv/work/src/randomio… if the file is opened in O_DIRECT mode. This can have big consequences. Look at the slow start of ext3 – it…
Comment: Why you can't rely on a replica for disaster recovery
August 7, 2010 By 25 Comments
… the DB and the fileystem. The most common linux file systems like ext3 are journaling file systems and as such they very, very, very rarely… a recovery on EXT3, buts its not outside the realm of possibility. Point being I suppose is that modern file system almost always… testment to some very careful file system design. The fact that a database running on top of that file system recovers as well is…
