Date: Tue, 1 Oct 2013 20:34:47 +0000 (UTC) From: Benedict Reuschling <bcr@FreeBSD.org> To: doc-committers@freebsd.org, svn-doc-projects@freebsd.org Subject: svn commit: r42795 - projects/zfsupdate-201307/en_US.ISO8859-1/books/handbook/zfs Message-ID: <201310012034.r91KYluV017135@svn.freebsd.org>
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Author: bcr Date: Tue Oct 1 20:34:47 2013 New Revision: 42795 URL: http://svnweb.freebsd.org/changeset/doc/42795 Log: Add a section about zpool iostat with a few examples. Modified: projects/zfsupdate-201307/en_US.ISO8859-1/books/handbook/zfs/chapter.xml Modified: projects/zfsupdate-201307/en_US.ISO8859-1/books/handbook/zfs/chapter.xml ============================================================================== --- projects/zfsupdate-201307/en_US.ISO8859-1/books/handbook/zfs/chapter.xml Tue Oct 1 19:30:26 2013 (r42794) +++ projects/zfsupdate-201307/en_US.ISO8859-1/books/handbook/zfs/chapter.xml Tue Oct 1 20:34:47 2013 (r42795) @@ -506,8 +506,51 @@ errors: No known data errors</screen> <sect2 id="zfs-zpool-iostat"> <title>Performance Monitoring</title> - <para></para> - </sect2> + <para>ZFS has a built-in monitoring isystem that can display + statistics about I/O happening on the pool in real-time. + Additionally, it shows the free and used space on the pool and + how much I/O bandwidth are currently utilized for read and + write operations. By default, all pools in the system will be + monitored and displayed. A pool name can be provided to just + monitor one pool. A basic example is provided below:</para> + +<screen>&prompt.root; <userinput>zpool iostat</userinput> + capacity operations bandwidth +pool alloc free read write read write +---------- ----- ----- ----- ----- ----- ----- +data 288G 1.53T 2 11 11.3K 57.1K</screen> + + <para>To monitor I/O activity on the pool continuously, a + number indicating the seconds after which to refresh the + display can be specified. ZFS will then print the next + statistic line after each intervall has been reached. Press + <keycombo + action="simul"><keycap>Ctrl</keycap><keycap>C</keycap></keycombo> + to stop this continuous monitoring. Alternatively, a second + whole number can be provided on the command line after the + intervall to indicate how many of these statistics should be + displayed in total.</para> + + <para>An even more detailed pool I/O statistic can be + displayed using the <literal>-v</literal> parameter. For + each storage device that is part of the pool ZFS will + provide a separate statistic line. This is helpful to + determine reads and writes on devices that slow down I/O on + the whole pool. In the following example, we have a + mirrored pool consisting of two devices. For each of these, + a separate line is shown with the current I/O + activity.</para> + +<screen>&prompt.root; <userinput>zpool iostat -v </userinput> + capacity operations bandwidth +pool alloc free read write read write +----------------------- ----- ----- ----- ----- ----- ----- +data 288G 1.53T 2 12 9.23K 61.5K + mirror 288G 1.53T 2 12 9.23K 61.5K + ada1 - - 0 4 5.61K 61.7K + ada2 - - 1 4 5.04K 61.7K +----------------------- ----- ----- ----- ----- ----- -----</screen> +</sect2> <sect2 id="zfs-zpool-split"> <title>Splitting a Storage Pool</title> @@ -533,12 +576,12 @@ errors: No known data errors</screen> <para></para> <para>A volume can be formatted with any filesystem on top of - it. This will appear to the user as if they are working with - that specific filesystem and not ZFS. This way, it can be - used to augment non-ZFS filesystems with ZFS features that - they do not have. For example, combining the ZFS compression - property together with a 250 MB volume allows to create a - compressed FAT filesystem.</para> + it. This will appear to the user as if they are working with + that specific filesystem and not ZFS. This way, it can be + used to augment non-ZFS filesystems with ZFS features that + they do not have. For example, combining the ZFS compression + property together with a 250 MB volume allows to create a + compressed FAT filesystem.</para> <screen>&prompt.root; <userinput>zfs create -V 250m -o compression=on tank/fat32</userinput> &prompt.root; <userinput>zfs list tank</userinput> @@ -564,12 +607,12 @@ Filesystem Size Used Avail Cap <para></para> - <para>It is possible to set user-defined properties in ZFS. They - become part of the pool configuration and can be used to provide - additional information about the pool or it's contents. To - distnguish these custom properties from the ones supplied by - ZFS by default, the colon (<literal>:</literal>) is used in the - property name.</para> + <para>It is possible to set user-defined properties in ZFS. + They become part of the pool configuration and can be used to + provide additional information about the pool or it's + contents. To distnguish these custom properties from the ones + supplied by ZFS by default, the colon (<literal>:</literal>) + is used in the property name.</para> <screen>&prompt.root; <userinput>zfs set custom:costcenter=1234</userinput> &prompt.root; <userinput>zfs get custom:costcenter</userinput>
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