Date: Mon, 25 Nov 2013 06:13:43 +0000 (UTC) From: Warren Block <wblock@FreeBSD.org> To: doc-committers@freebsd.org, svn-doc-projects@freebsd.org Subject: svn commit: r43243 - projects/zfsupdate-201307/en_US.ISO8859-1/books/handbook/zfs Message-ID: <201311250613.rAP6DhIU004622@svn.freebsd.org>
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Author: wblock Date: Mon Nov 25 06:13:43 2013 New Revision: 43243 URL: http://svnweb.freebsd.org/changeset/doc/43243 Log: Whitespace-only fixes, translators please ignore. 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 Mon Nov 25 05:58:08 2013 (r43242) +++ projects/zfsupdate-201307/en_US.ISO8859-1/books/handbook/zfs/chapter.xml Mon Nov 25 06:13:43 2013 (r43243) @@ -567,12 +567,12 @@ errors: No known data errors</screen> as in the case of RAID-Z, the other option is to add a vdev to the pool. It is possible, but discouraged, to mix vdev types. ZFS stripes data across each of the vdevs. For example, if - there are two mirror vdevs, then this is effectively a <acronym>RAID</acronym> - 10, striping the writes across the two sets of mirrors. - Because of the way that space is allocated in <acronym>ZFS</acronym> to attempt - to have each vdev reach 100% full at the same time, there is a - performance penalty if the vdevs have different amounts of - free space.</para> + there are two mirror vdevs, then this is effectively a + <acronym>RAID</acronym> 10, striping the writes across the two + sets of mirrors. Because of the way that space is allocated + in <acronym>ZFS</acronym> to attempt to have each vdev reach + 100% full at the same time, there is a performance penalty if + the vdevs have different amounts of free space.</para> <para>Currently, vdevs cannot be removed from a zpool, and disks can only be removed from a mirror if there is enough remaining @@ -604,8 +604,8 @@ errors: No known data errors</screen> available, but performance may be impacted because missing data will need to be calculated from the available redundancy. To restore the vdev to a fully functional state, the failed - physical device must be replaced, and <acronym>ZFS</acronym> must - be instructed to begin the + physical device must be replaced, and <acronym>ZFS</acronym> + must be instructed to begin the <link linkend="zfs-term-resilver">resilver</link> operation, where data that was on the failed device will be recalculated from available redundancy and written to the replacement @@ -689,13 +689,13 @@ errors: No known data errors</screen> <sect2 xml:id="zfs-zpool-history"> <title>Displaying Recorded Pool History</title> - <para><acronym>ZFS</acronym> records all the commands that were issued to - administer the pool. These include the creation of datasets, - changing properties, or when a disk has been replaced in - the pool. This history is useful for reviewing how a pool was created and - which user did a specific action and when. - History is not kept in a log file, but is a part of the pool - itself. Because of that, history cannot be altered + <para><acronym>ZFS</acronym> records all the commands that were + issued to administer the pool. These include the creation of + datasets, changing properties, or when a disk has been + replaced in the pool. This history is useful for reviewing + how a pool was created and which user did a specific action + and when. History is not kept in a log file, but is a part of + the pool itself. Because of that, history cannot be altered after the fact unless the pool is destroyed. The command to review this history is aptly named <command>zpool history</command>:</para> @@ -732,11 +732,10 @@ History for 'tank': 2013-02-27.18:51:13 [internal create txg:55] dataset = 39 2013-02-27.18:51:18 zfs create tank/backup</screen> - <para>A more-detailed history is invoked by - adding <literal>-l</literal>. - Log records are shown in long format, including information - like the name of the user who issued the command and the hostname on - which the change was made.</para> + <para>A more-detailed history is invoked by adding + <literal>-l</literal>. Log records are shown in long format, + including information like the name of the user who issued the + command and the hostname on which the change was made.</para> <screen>&prompt.root; <userinput>zpool history -l</userinput> History for 'tank': @@ -758,9 +757,9 @@ History for 'tank': <para>Both options to <command>zpool history</command> can be combined to give the most detailed information possible for - any given pool. Pool history provides valuable - information when tracking down what actions were - performed or when more detailed output is needed for debugging.</para> + any given pool. Pool history provides valuable information + when tracking down what actions were performed or when more + detailed output is needed for debugging.</para> </sect2> <sect2 xml:id="zfs-zpool-iostat"> @@ -820,11 +819,11 @@ data 288G 1.53T <para>A pool consisting of one or more mirror vdevs can be split into a second pool. The last member of each mirror (unless otherwise specified) is detached and used to create a - new pool containing the same data. It is recommended that - the operation first be attempted with the <option>-n</option> - parameter. The details of the proposed - operation are displayed without actually performing it. This helps - ensure the operation will happen as expected.</para> + new pool containing the same data. It is recommended that the + operation first be attempted with the <option>-n</option> + parameter. The details of the proposed operation are + displayed without actually performing it. This helps ensure + the operation will happen as expected.</para> </sect2> </sect1> @@ -841,18 +840,17 @@ data 288G 1.53T <title>Creating & Destroying Datasets</title> <para>Unlike traditional disks and volume managers, space - in <acronym>ZFS</acronym> is not preallocated. - Wtraditional file systems, once all of the space was - partitioned and assigned, there was no way to - add an additional file system without adding a new disk. - With <acronym>ZFS</acronym>, new file systems can be created at any time. - Each - <link linkend="zfs-term-dataset"><emphasis>dataset</emphasis></link> has - properties including features like compression, deduplication, - caching and quoteas, as well as other useful properties like - readonly, case sensitivity, network file sharing, and a mount - point. Each separate dataset can be administered, - <link linkend="zfs-zfs-allow">delegated</link>, + in <acronym>ZFS</acronym> is not preallocated. Wtraditional + file systems, once all of the space was partitioned and + assigned, there was no way to add an additional file system + without adding a new disk. With <acronym>ZFS</acronym>, new + file systems can be created at any time. Each <link + linkend="zfs-term-dataset"><emphasis>dataset</emphasis></link> + has properties including features like compression, + deduplication, caching and quoteas, as well as other useful + properties like readonly, case sensitivity, network file + sharing, and a mount point. Each separate dataset can be + administered, <link linkend="zfs-zfs-allow">delegated</link>, <link linkend="zfs-zfs-send">replicated</link>, <link linkend="zfs-zfs-snapshot">snapshoted</link>, <link linkend="zfs-zfs-jail">jailed</link>, and destroyed as a @@ -871,7 +869,7 @@ data 288G 1.53T is asynchronous, and the free space may take several minutes to appear in the pool. The <literal>freeing</literal> property, accessible with <command>zpool get freeing - <replaceable>poolname</replaceable></command> indicates how + <replaceable>poolname</replaceable></command> indicates how many datasets are having their blocks freed in the background. If there are child datasets, like <link linkend="zfs-term-snapshot">snapshots</link> or other @@ -894,16 +892,17 @@ data 288G 1.53T <filename>/dev/zvol/<replaceable>poolname</replaceable>/<replaceable>dataset</replaceable></filename>. This allows the volume to be used for other file systems, to back the disks of a virtual machine, or to be exported using - protocols like <acronym>iSCSI</acronym> or <acronym>HAST</acronym>.</para> + protocols like <acronym>iSCSI</acronym> or + <acronym>HAST</acronym>.</para> - <para>A volume can be formatted with any file system. - To the user, it will appear as if they are working with - a regular disk using that specific filesystem and not <acronym>ZFS</acronym>. - Putting ordinary file systems on - <acronym>ZFS</acronym> volumes provides features those file systems would not normally have. For example, - using the compression property on a - 250 MB volume allows creation of a compressed <acronym>FAT</acronym> - filesystem.</para> + <para>A volume can be formatted with any file system. To the + user, it will appear as if they are working with a regular + disk using that specific filesystem and not + <acronym>ZFS</acronym>. Putting ordinary file systems on + <acronym>ZFS</acronym> volumes provides features those file + systems would not normally have. For example, using the + compression property on a 250 MB volume allows creation + of a compressed <acronym>FAT</acronym> filesystem.</para> <screen>&prompt.root; <userinput>zfs create -V 250m -o compression=on tank/fat32</userinput> &prompt.root; <userinput>zfs list tank</userinput> @@ -927,16 +926,16 @@ Filesystem Size Used Avail Cap <title>Renaming a Dataset</title> <para>The name of a dataset can be changed with - <command>zfs rename</command>. <command>rename</command> can also be - used to change the parent of a dataset. Renaming a dataset to - be under a different parent dataset will change the value of - those properties that are inherited by the child dataset. - When a dataset is renamed, it is unmounted and then remounted - in the new location (inherited from the parent dataset). This - behavior can be prevented with <option>-u</option>. - Due to the nature of snapshots, they cannot be - renamed outside of the parent dataset. To rename a recursive - snapshot, specify <option>-r</option>, and all + <command>zfs rename</command>. <command>rename</command> can + also be used to change the parent of a dataset. Renaming a + dataset to be under a different parent dataset will change the + value of those properties that are inherited by the child + dataset. When a dataset is renamed, it is unmounted and then + remounted in the new location (inherited from the parent + dataset). This behavior can be prevented with + <option>-u</option>. Due to the nature of snapshots, they + cannot be renamed outside of the parent dataset. To rename a + recursive snapshot, specify <option>-r</option>, and all snapshots with the same specified snapshot will be renamed.</para> </sect2> @@ -949,19 +948,21 @@ Filesystem Size Used Avail Cap automatically inherited from the parent dataset, but can be overridden locally. Set a property on a dataset with <command>zfs set - <replaceable>property</replaceable>=<replaceable>value</replaceable> - <replaceable>dataset</replaceable></command>. Most properties - have a limited set of valid values, <command>zfs get</command> - will display each possible property and its valid values. - Most properties can be reverted to their inherited values - using <command>zfs inherit</command>.</para> - - <para>It is possible to set user-defined properties. - They become part of the dataset configuration and can be used - to provide additional information about the dataset or its + <replaceable>property</replaceable>=<replaceable>value</replaceable> + <replaceable>dataset</replaceable></command>. Most + properties have a limited set of valid values, + <command>zfs get</command> will display each possible property + and its valid values. Most properties can be reverted to + their inherited values using + <command>zfs inherit</command>.</para> + + <para>It is possible to set user-defined properties. They + become part of the dataset configuration and can be used to + provide additional information about the dataset or its contents. To distinguish these custom properties from the - ones supplied as part of <acronym>ZFS</acronym>, a colon (<literal>:</literal>) - is used to create a custom namespace for the property.</para> + ones supplied as part of <acronym>ZFS</acronym>, a colon + (<literal>:</literal>) is used to create a custom namespace + for the property.</para> <screen>&prompt.root; <userinput>zfs set <replaceable>custom</replaceable>:<replaceable>costcenter</replaceable>=<replaceable>1234</replaceable> <replaceable>tank</replaceable></userinput> &prompt.root; <userinput>zfs get <replaceable>custom</replaceable>:<replaceable>costcenter</replaceable> <replaceable>tank</replaceable></userinput> @@ -969,11 +970,10 @@ NAME PROPERTY VALUE SOURCE tank custom:costcenter 1234 local</screen> <para>To remove a custom property, use - <command>zfs inherit</command> with - <option>-r</option>. If the custom property is not - defined in any of the parent datasets, it will be removed - completely (although the changes are still recorded in the - pool's history).</para> + <command>zfs inherit</command> with <option>-r</option>. If + the custom property is not defined in any of the parent + datasets, it will be removed completely (although the changes + are still recorded in the pool's history).</para> <screen>&prompt.root; <userinput>zfs inherit -r <replaceable>custom</replaceable>:<replaceable>costcenter</replaceable> <replaceable>tank</replaceable></userinput> &prompt.root; <userinput>zfs get <replaceable>custom</replaceable>:<replaceable>costcenter</replaceable> <replaceable>tank</replaceable></userinput> @@ -989,12 +989,11 @@ tank custom:costcenter - <para><link linkend="zfs-term-snapshot">Snapshots</link> are one of the most powerful features of <acronym>ZFS</acronym>. A snapshot provides a point-in-time copy of the dataset. The - parent dataset can be easily rolled back to that snapshot state. Create a - snapshot with <command>zfs snapshot - <replaceable>dataset</replaceable>@<replaceable>snapshotname</replaceable></command>. + parent dataset can be easily rolled back to that snapshot + state. Create a snapshot with <command>zfs snapshot + <replaceable>dataset</replaceable>@<replaceable>snapshotname</replaceable></command>. Adding <option>-r</option> creates a snapshot recursively, - with the same name on all child - datasets.</para> + with the same name on all child datasets.</para> <para>Snapshots are mounted in a hidden directory under the parent dataset: <filename @@ -1182,8 +1181,8 @@ tank custom:costcenter - Reservation</link>, with the general format <literal>refreservation=<replaceable>size</replaceable></literal>.</para> - <para>This command shows any reservations or refreservations that exist on - <filename>storage/home/bob</filename>:</para> + <para>This command shows any reservations or refreservations + that exist on <filename>storage/home/bob</filename>:</para> <screen>&prompt.root; <userinput>zfs get reservation storage/home/bob</userinput> &prompt.root; <userinput>zfs get refreservation storage/home/bob</userinput></screen> @@ -1202,25 +1201,24 @@ tank custom:costcenter - <link linkend="zfs-term-deduplication">Deduplication</link> uses the checksum of each block to detect duplicate blocks. When a new block is a duplicate of an existing block, - <acronym>ZFS</acronym> writes an additional reference to - the existing data instead of the whole duplicate block. This can offer - tremendous space savings if the data contains many discreet - copies of the file information. Be warned: deduplication requires an - extremely large amount of memory, and most of the space - savings can be had without the extra cost by enabling - compression instead.</para> + <acronym>ZFS</acronym> writes an additional reference to the + existing data instead of the whole duplicate block. This can + offer tremendous space savings if the data contains many + discreet copies of the file information. Be warned: + deduplication requires an extremely large amount of memory, + and most of the space savings can be had without the extra + cost by enabling compression instead.</para> <para>To activate deduplication, set the <literal>dedup</literal> property on the target pool:</para> <screen>&prompt.root; <userinput>zfs set dedup=on <replaceable>pool</replaceable></userinput></screen> - <para>Only new data being - written to the pool will be deduplicated. Data that has - already been written to the pool will not be deduplicated merely by - activating this option. As such, a pool with a freshly - activated deduplication property will look something like this - example:</para> + <para>Only new data being written to the pool will be + deduplicated. Data that has already been written to the pool + will not be deduplicated merely by activating this option. As + such, a pool with a freshly activated deduplication property + will look something like this example:</para> <screen>&prompt.root; <userinput>zpool list</userinput> NAME SIZE ALLOC FREE CAP DEDUP HEALTH ALTROOT @@ -1228,10 +1226,10 @@ pool 2.84G 2.19M 2.83G 0% 1.00x ONLINE <para>The <literal>DEDUP</literal> column shows the actual rate of deduplication for the pool. A value of - <literal>1.00x</literal> shows that data has not been deduplicated - yet. In the next example, - the ports tree is copied three times into different - directories on the deduplicated pool created above.</para> + <literal>1.00x</literal> shows that data has not been + deduplicated yet. In the next example, the ports tree is + copied three times into different directories on the + deduplicated pool created above.</para> <screen>&prompt.root; <userinput>zpool list</userinput> for d in dir1 dir2 dir3; do @@ -1247,13 +1245,14 @@ pool 2.84G 20.9M 2.82G 0% 3.00x ONLINE - <para>The <literal>DEDUP</literal> column now shows a factor of <literal>3.00x</literal>. The multiple copies of the ports tree data was detected and deduplicated, taking only a third - of the space. The potential for space savings - can be enormous, but comes at the cost of having enough memory - to keep track of the deduplicated blocks.</para> + of the space. The potential for space savings can be + enormous, but comes at the cost of having enough memory to + keep track of the deduplicated blocks.</para> <para>Deduplication is not always beneficial, especially when - there is not much redundant data on a pool. <acronym>ZFS</acronym> - can show potential space savings by simulating deduplication on an existing pool:</para> + there is not much redundant data on a pool. + <acronym>ZFS</acronym> can show potential space savings by + simulating deduplication on an existing pool:</para> <screen>&prompt.root; <userinput>zdb -S <replaceable>pool</replaceable></userinput> Simulated DDT histogram: @@ -1282,12 +1281,12 @@ dedup = 1.05, compress = 1.11, copies = <literal>1.16</literal> is a very poor ratio that is mostly influenced by compression. Activating deduplication on this pool would not save any significant amount of space. Using - the formula <emphasis>dedup * compress / copies = deduplication - ratio</emphasis>, system administrators can plan the - storage allocation more towards having multiple copies of data - or by having a decent compression rate in order to utilize the - space savings that deduplication provides. As a rule of - thumb, compression should be used before deduplication + the formula <emphasis>dedup * compress / copies = + deduplication ratio</emphasis>, system administrators can plan + the storage allocation more towards having multiple copies of + data or by having a decent compression rate in order to + utilize the space savings that deduplication provides. As a + rule of thumb, compression should be used before deduplication due to the much lower memory requirements.</para> </sect2> @@ -1296,15 +1295,16 @@ dedup = 1.05, compress = 1.11, copies = <para><command>zfs jail</command> and the corresponding <literal>jailed</literal> property are used to delegate a - <acronym>ZFS</acronym> dataset to a <link - linkend="jails">Jail</link>. <command>zfs jail - <replaceable>jailid</replaceable></command> attaches a dataset - to the specified jail, and <command>zfs unjail</command> - detaches it. For the dataset to be administered from - within a jail, the <literal>jailed</literal> property must be - set. Once a dataset is jailed, it can no longer be mounted on - the host because the jail administrator may have set - unacceptable mount points.</para> + <acronym>ZFS</acronym> dataset to a + <link linkend="jails">Jail</link>. + <command>zfs jail <replaceable>jailid</replaceable></command> + attaches a dataset to the specified jail, and + <command>zfs unjail</command> detaches it. For the dataset to + be administered from within a jail, the + <literal>jailed</literal> property must be set. Once a + dataset is jailed, it can no longer be mounted on the host + because the jail administrator may have set unacceptable mount + points.</para> </sect2> </sect1> @@ -1633,8 +1633,8 @@ vfs.zfs.vdev.cache.size="5M"</programlis with eight disks of 1 TB, the volume will provide 5 TB of usable space and still be able to operate with three faulted disks. &sun; - recommends no more than nine disks in a single vdev. - If the configuration has more disks, it is + recommends no more than nine disks in a single + vdev. If the configuration has more disks, it is recommended to divide them into separate vdevs and the pool data will be striped across them.</para> @@ -1793,13 +1793,12 @@ vfs.zfs.vdev.cache.size="5M"</programlis written to a different block rather than overwriting the old data in place. Only when this write is complete is the metadata then updated to point to the new location. - In the event of a shorn - write (a system crash or power loss in the middle of - writing a file), the entire original contents of the - file are still available and the incomplete write is - discarded. This also means that <acronym>ZFS</acronym> - does not require a &man.fsck.8; after an unexpected - shutdown.</entry> + In the event of a shorn write (a system crash or power + loss in the middle of writing a file), the entire + original contents of the file are still available and + the incomplete write is discarded. This also means that + <acronym>ZFS</acronym> does not require a &man.fsck.8; + after an unexpected shutdown.</entry> </row> <row> @@ -2019,11 +2018,11 @@ vfs.zfs.vdev.cache.size="5M"</programlis check of all the data stored on the pool ensures the recovery of any corrupted blocks before they are needed. A scrub is not required after an unclean shutdown, but - it is recommended that a <command>scrub</command> is run at least once - each quarter. Checksums of each block are tested as - they are read in normal use, but a scrub operation makes - sure even infrequently used blocks are checked for - silent corruption.</entry> + it is recommended that a <command>scrub</command> is run + at least once each quarter. Checksums of each block are + tested as they are read in normal use, but a scrub + operation makes sure even infrequently used blocks are + checked for silent corruption.</entry> </row> <row>help
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