Changes between Version 3 and Version 4 of jazz/12-06-02

Timestamp:

Jun 3, 2012, 11:40:52 AM (12 years ago)

Author:

jazz

Comment:

--

jazz/12-06-02

@@ -43 +43 @@
 AIX vio ioo is a read ahead cache system to improve speed of transfers when doing sequential reads.
 }}}
+  * [http://stackoverflow.com/questions/4888067/how-to-get-linux-kernel-page-size-programatically How to get linux kernel page size programatically]
+{{{ 
+jazz@jazzbook:~$ cat /proc/meminfo | grep Mapped
+Mapped:            74764 kB
+jazz@jazzbook:~$ cat /proc/vmstat | grep "nr_mapped"
+nr_mapped 18691
+jazz@jazzbook:~$ A=$(cat /proc/meminfo | grep Mapped | awk '{ print $2 }')
+jazz@jazzbook:~$ B=$(cat /proc/vmstat | grep "nr_mapped" | awk '{ print $2 }')
+jazz@jazzbook:~$ echo $(($A/$B))
+4
+}}}
   * [參考五] [http://www.linuxpinguin.de/2011/01/performance-increase-through-bigger-readahead-buffers/ Performance increase through bigger readahead buffers] - 以下示範是把預設的 RA 由 256 提升到 1024（注意是設定'''整顆硬碟'''，而非特定磁區）
 {{{
@@ -57 +68 @@
 ~$ sudo blockdev --setra 1024 /dev/sda
 }}}
+ * 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。'''
+{{{
+#!text
+The following systems support extents:
+
+    ASM - Automatic Storage Management - Oracle's database-oriented filesystem.
+    BFS - BeOS, Zeta and Haiku operating systems.
+    Btrfs - GPL'd extent based file storage for Linux.
+    Ext4 - Linux filesystem (when the configuration enables extents — the default in Linux since version 2.6.23).
+    Files-11 - Digital Equipment Corporation (subsequently Hewlett-Packard) OpenVMS filesystem.
+    HFS and HFS Plus - Hierarchical File System - Apple Macintosh filesystems.
+    HPFS - High Performance File Syzstem - OS/2 and eComStation.
+    JFS - Journaled File System - Used by AIX, OS/2/eComStation and Linux operating systems.
+    Microsoft SQL Server - Versions 2000-2008 supports extents of up to 64KB [1].
+    Multi-Programming Executive - Filesystem by Hewlett-Packard.
+    NTFS - Microsoft's latest-generation file system [1]
+    OCFS2 - Oracle Cluster File System - a shared disk file system for Linux.
+    Reiser4 - Linux filesystem (in "extents" mode).
+    SINTRAN III - File system used by early computer company Norsk Data.
+    UDF - Universal Disk Format - Standard for optical media.
+    VERITAS File System - Enabled via the pre-allocation API and CLI.
+    XFS - SGI's second generation file system.[2]
+}}}