13197ebdbSTheodore Ts'oWhat: /sys/fs/ext4/<disk>/mb_stats 23197ebdbSTheodore Ts'oDate: March 2008 33197ebdbSTheodore Ts'oContact: "Theodore Ts'o" <tytso@mit.edu> 43197ebdbSTheodore Ts'oDescription: 53197ebdbSTheodore Ts'o Controls whether the multiblock allocator should 63197ebdbSTheodore Ts'o collect statistics, which are shown during the unmount. 73197ebdbSTheodore Ts'o 1 means to collect statistics, 0 means not to collect 83197ebdbSTheodore Ts'o statistics 93197ebdbSTheodore Ts'o 103197ebdbSTheodore Ts'oWhat: /sys/fs/ext4/<disk>/mb_group_prealloc 113197ebdbSTheodore Ts'oDate: March 2008 123197ebdbSTheodore Ts'oContact: "Theodore Ts'o" <tytso@mit.edu> 133197ebdbSTheodore Ts'oDescription: 143197ebdbSTheodore Ts'o The multiblock allocator will round up allocation 153197ebdbSTheodore Ts'o requests to a multiple of this tuning parameter if the 163197ebdbSTheodore Ts'o stripe size is not set in the ext4 superblock 173197ebdbSTheodore Ts'o 183197ebdbSTheodore Ts'oWhat: /sys/fs/ext4/<disk>/mb_max_to_scan 193197ebdbSTheodore Ts'oDate: March 2008 203197ebdbSTheodore Ts'oContact: "Theodore Ts'o" <tytso@mit.edu> 213197ebdbSTheodore Ts'oDescription: 223197ebdbSTheodore Ts'o The maximum number of extents the multiblock allocator 233197ebdbSTheodore Ts'o will search to find the best extent 243197ebdbSTheodore Ts'o 253197ebdbSTheodore Ts'oWhat: /sys/fs/ext4/<disk>/mb_min_to_scan 263197ebdbSTheodore Ts'oDate: March 2008 273197ebdbSTheodore Ts'oContact: "Theodore Ts'o" <tytso@mit.edu> 283197ebdbSTheodore Ts'oDescription: 293197ebdbSTheodore Ts'o The minimum number of extents the multiblock allocator 303197ebdbSTheodore Ts'o will search to find the best extent 313197ebdbSTheodore Ts'o 323197ebdbSTheodore Ts'oWhat: /sys/fs/ext4/<disk>/mb_order2_req 333197ebdbSTheodore Ts'oDate: March 2008 343197ebdbSTheodore Ts'oContact: "Theodore Ts'o" <tytso@mit.edu> 353197ebdbSTheodore Ts'oDescription: 363197ebdbSTheodore Ts'o Tuning parameter which controls the minimum size for 373197ebdbSTheodore Ts'o requests (as a power of 2) where the buddy cache is 383197ebdbSTheodore Ts'o used 393197ebdbSTheodore Ts'o 403197ebdbSTheodore Ts'oWhat: /sys/fs/ext4/<disk>/mb_stream_req 413197ebdbSTheodore Ts'oDate: March 2008 423197ebdbSTheodore Ts'oContact: "Theodore Ts'o" <tytso@mit.edu> 433197ebdbSTheodore Ts'oDescription: 443197ebdbSTheodore Ts'o Files which have fewer blocks than this tunable 453197ebdbSTheodore Ts'o parameter will have their blocks allocated out of a 463197ebdbSTheodore Ts'o block group specific preallocation pool, so that small 473197ebdbSTheodore Ts'o files are packed closely together. Each large file 483197ebdbSTheodore Ts'o will have its blocks allocated out of its own unique 493197ebdbSTheodore Ts'o preallocation pool. 503197ebdbSTheodore Ts'o 516f9524e9SLukas CzernerWhat: /sys/fs/ext4/<disk>/inode_readahead_blks 523197ebdbSTheodore Ts'oDate: March 2008 533197ebdbSTheodore Ts'oContact: "Theodore Ts'o" <tytso@mit.edu> 543197ebdbSTheodore Ts'oDescription: 553197ebdbSTheodore Ts'o Tuning parameter which controls the maximum number of 563197ebdbSTheodore Ts'o inode table blocks that ext4's inode table readahead 573197ebdbSTheodore Ts'o algorithm will pre-read into the buffer cache 583197ebdbSTheodore Ts'o 593197ebdbSTheodore Ts'oWhat: /sys/fs/ext4/<disk>/delayed_allocation_blocks 603197ebdbSTheodore Ts'oDate: March 2008 613197ebdbSTheodore Ts'oContact: "Theodore Ts'o" <tytso@mit.edu> 623197ebdbSTheodore Ts'oDescription: 633197ebdbSTheodore Ts'o This file is read-only and shows the number of blocks 643197ebdbSTheodore Ts'o that are dirty in the page cache, but which do not 653197ebdbSTheodore Ts'o have their location in the filesystem allocated yet. 663197ebdbSTheodore Ts'o 673197ebdbSTheodore Ts'oWhat: /sys/fs/ext4/<disk>/lifetime_write_kbytes 683197ebdbSTheodore Ts'oDate: March 2008 693197ebdbSTheodore Ts'oContact: "Theodore Ts'o" <tytso@mit.edu> 703197ebdbSTheodore Ts'oDescription: 713197ebdbSTheodore Ts'o This file is read-only and shows the number of kilobytes 723197ebdbSTheodore Ts'o of data that have been written to this filesystem since it was 733197ebdbSTheodore Ts'o created. 743197ebdbSTheodore Ts'o 753197ebdbSTheodore Ts'oWhat: /sys/fs/ext4/<disk>/session_write_kbytes 763197ebdbSTheodore Ts'oDate: March 2008 773197ebdbSTheodore Ts'oContact: "Theodore Ts'o" <tytso@mit.edu> 783197ebdbSTheodore Ts'oDescription: 793197ebdbSTheodore Ts'o This file is read-only and shows the number of 803197ebdbSTheodore Ts'o kilobytes of data that have been written to this 813197ebdbSTheodore Ts'o filesystem since it was mounted. 8211013911SAndreas Dilger 8311013911SAndreas DilgerWhat: /sys/fs/ext4/<disk>/inode_goal 8411013911SAndreas DilgerDate: June 2008 8511013911SAndreas DilgerContact: "Theodore Ts'o" <tytso@mit.edu> 8611013911SAndreas DilgerDescription: 8711013911SAndreas Dilger Tuning parameter which (if non-zero) controls the goal 886f9524e9SLukas Czerner inode used by the inode allocator in preference to 896f9524e9SLukas Czerner all other allocation heuristics. This is intended for 9011013911SAndreas Dilger debugging use only, and should be 0 on production 9111013911SAndreas Dilger systems. 926f9524e9SLukas Czerner 936f9524e9SLukas CzernerWhat: /sys/fs/ext4/<disk>/max_writeback_mb_bump 946f9524e9SLukas CzernerDate: September 2009 956f9524e9SLukas CzernerContact: "Theodore Ts'o" <tytso@mit.edu> 966f9524e9SLukas CzernerDescription: 976f9524e9SLukas Czerner The maximum number of megabytes the writeback code will 986f9524e9SLukas Czerner try to write out before move on to another inode. 9967a5da56SZheng Liu 10067a5da56SZheng LiuWhat: /sys/fs/ext4/<disk>/extent_max_zeroout_kb 10167a5da56SZheng LiuDate: August 2012 10267a5da56SZheng LiuContact: "Theodore Ts'o" <tytso@mit.edu> 10367a5da56SZheng LiuDescription: 10467a5da56SZheng Liu The maximum number of kilobytes which will be zeroed 10567a5da56SZheng Liu out in preference to creating a new uninitialized 10667a5da56SZheng Liu extent when manipulating an inode's extent tree. Note 10767a5da56SZheng Liu that using a larger value will increase the 10867a5da56SZheng Liu variability of time necessary to complete a random 10967a5da56SZheng Liu write operation (since a 4k random write might turn 11067a5da56SZheng Liu into a much larger write due to the zeroout 11167a5da56SZheng Liu operation). 112*bc1d69d6SKonstantin Khlebnikov 113*bc1d69d6SKonstantin KhlebnikovWhat: /sys/fs/ext4/<disk>/journal_task 114*bc1d69d6SKonstantin KhlebnikovDate: February 2019 115*bc1d69d6SKonstantin KhlebnikovContact: "Theodore Ts'o" <tytso@mit.edu> 116*bc1d69d6SKonstantin KhlebnikovDescription: 117*bc1d69d6SKonstantin Khlebnikov This file is read-only and shows the pid of journal thread in 118*bc1d69d6SKonstantin Khlebnikov current pid-namespace or 0 if task is unreachable. 119