Changes between Version 4 and Version 5 of jazz/12-06-02


Ignore:
Timestamp:
Jun 3, 2012, 11:51:55 AM (12 years ago)
Author:
jazz
Comment:

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  • jazz/12-06-02

    v4 v5  
    3737~$ getconf PAGE_SIZE
    3838}}}
    39  * 結論(3):'''除了加大 Block Size 之外，最常用的方式是啟動 read ahead （運用快取來提昇硬碟循序讀取的效率）'''
    40   * [參考四] [http://forums.opensuse.org/forums/english/get-technical-help-here/install-boot-login/437078-changing-pagesize-kernel.html#post2152312 Changing PAGESIZE in kernel]
    41 {{{
    42 #!text
    43 AIX vio ioo is a read ahead cache system to improve speed of transfers when doing sequential reads.
    44 }}}
    4539  * [http://stackoverflow.com/questions/4888067/how-to-get-linux-kernel-page-size-programatically How to get linux kernel page size programatically]
    4640{{{
    … …  
    5347jazz@jazzbook:~$ echo $(($A/$B))
    54484
     49}}}
     50 * 結論(3):'''除了加大 Block Size 之外，最常用的方式是啟動 read ahead （運用快取來提昇硬碟循序讀取的效率）'''
     51  * [參考四] [http://forums.opensuse.org/forums/english/get-technical-help-here/install-boot-login/437078-changing-pagesize-kernel.html#post2152312 Changing PAGESIZE in kernel]
     52{{{
     53#!text
     54AIX vio ioo is a read ahead cache system to improve speed of transfers when doing sequential reads.
    5555}}}
    5656  * [參考五] [http://www.linuxpinguin.de/2011/01/performance-increase-through-bigger-readahead-buffers/ Performance increase through bigger readahead buffers] - 以下示範是把預設的 RA 由 256 提升到 1024（注意是設定'''整顆硬碟'''，而非特定磁區）
    … …  
    6969}}}
    7070 * 結論(4):'''可以使用支援[http://en.wikipedia.org/wiki/Extent_%28file_systems%29 Extent]的檔案系統，來預留較大的寫入區塊。'''
     71  * [參考六] [http://superuser.com/questions/242055/mounting-ext4-fs-with-block-size-of-65536 mounting ext4 fs with block size of 65536]
     72{{{
     73I'd say use 4kb blocks for compatibility and use extents and
     74stripe stride-width options on create/mount to get block allocations
     75in accordance with erase block size of your flash media.
     76Make sure also that partition is aligned to this erase block size too!
     77}}}
     78  * [參考七] [http://stackoverflow.com/questions/9611436/ubuntu-create-partition-block-more-than-4k ubuntu create partition block more than 4k]
     79{{{
     80You can use fallocate function and any fs with extents: ext4, btrfs, JFS, XFS.
     81Even with 4kb block size: "A single extent in ext4 can map up to 128 MiB of
     82contiguous space".
     83}}}
    7184{{{
    7285#!text
     86An extent is a contiguous area of storage in a computer file system, reserved for a file.
     87When a process creates a file, file-system management software allocates a whole extent.
     88
    7389The following systems support extents:
    7490