| <head> |
| <title>vac(1) - Plan 9 from User Space</title> |
| <meta content="text/html; charset=utf-8" http-equiv=Content-Type> |
| </head> |
| <body bgcolor=#ffffff> |
| <table border=0 cellpadding=0 cellspacing=0 width=100%> |
| <tr height=10><td> |
| <tr><td width=20><td> |
| <tr><td width=20><td><b>VAC(1)</b><td align=right><b>VAC(1)</b> |
| <tr><td width=20><td colspan=2> |
| <br> |
| <p><font size=+1><b>NAME </b></font><br> |
| |
| <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> |
| |
| vac – create a vac archive on Venti<br> |
| |
| </table> |
| <p><font size=+1><b>SYNOPSIS </b></font><br> |
| |
| <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> |
| |
| <tt><font size=+1>vac</font></tt> [ <tt><font size=+1>−mqsv</font></tt> ] [ <tt><font size=+1>−b</font></tt> <i>blocksize</i> ] [ <tt><font size=+1>−d</font></tt> <i>oldvacfile</i> ] [ <tt><font size=+1>−e</font></tt> <i>exclude</i> |
| ] [ <tt><font size=+1>−f</font></tt> <i>vacfile</i> ] [ <tt><font size=+1>−i</font></tt> <i>name</i> ] [ <tt><font size=+1>−h</font></tt> <i>host</i> ] <i>file ...<br> |
| </i> |
| </table> |
| <p><font size=+1><b>DESCRIPTION </b></font><br> |
| |
| <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> |
| |
| <i>Vac</i> creates an archival copy of Plan 9 file trees on Venti. It |
| can be used to build a simple backup system. One of the unusual |
| properties of Venti is that duplicate blocks are detected and |
| coalesced. When <i>vac</i> is used on a file tree that shares data with |
| an existing archive, the consumption of storage will be approximately |
| equal to an incremental backup. This reduction in storage consumption |
| occurs transparently to the user. |
| <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> |
| |
| As an optimization, the <tt><font size=+1>−d</font></tt> and <tt><font size=+1>−q</font></tt> options, described below, can |
| be used to explicitly create an archive relative to an existing |
| archive. These options do not change the resulting archive generated |
| by <i>vac</i>, but simply reduce the number of write operations to Venti. |
| |
| <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> |
| |
| The output of <i>vac</i> is the hexadecimal representation of the Sha1 |
| fingerprint of the root of the archive, in this format:<br> |
| |
| <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> |
| |
| <tt><font size=+1>vac:64daefaecc4df4b5cb48a368b361ef56012a4f46<br> |
| |
| <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> |
| </font></tt> |
| |
| </table> |
| Option to <i>vac</i> are:<br> |
| <tt><font size=+1>−b</font></tt> <i>blocksize<br> |
| </i> |
| <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> |
| |
| Specifies the block size that data will be broken into. The units |
| for the size can be specified by appending <tt><font size=+1>k</font></tt> to indicate kilobytes. |
| The default is 8k. The size must be in the range of 512 bytes |
| to 52k.<br> |
| |
| </table> |
| <tt><font size=+1>−d</font></tt> <i>oldvacfile<br> |
| </i> |
| <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> |
| |
| Reduce the number of blocks written to Venti by comparing the |
| files to be stored with the contents of an existing <i>vac</i> file tree |
| given by <i>oldvacfile</i>.<br> |
| |
| </table> |
| <tt><font size=+1>−e</font></tt> <i>exclude<br> |
| </i> |
| <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> |
| |
| Do not include the file or directory specified by <i>exclude</i>. This |
| option may be repeated multiple times.<br> |
| |
| </table> |
| <tt><font size=+1>−f</font></tt> <i>vacfile<br> |
| </i> |
| <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> |
| |
| The results of <i>vac</i> are place in <i>vacfile</i>, or the standard output |
| if no file is given.<br> |
| |
| </table> |
| <tt><font size=+1>−i</font></tt> <i>name<br> |
| </i> |
| <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> |
| |
| Include standard input as one of the input files, storing it in |
| the archive with the specified <i>name</i>.<br> |
| |
| </table> |
| <tt><font size=+1>−h</font></tt> <i>host<br> |
| </i> |
| <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> |
| |
| The network address of the Venti server. The default is taken |
| from the environment variable <tt><font size=+1>venti</font></tt>.<br> |
| |
| </table> |
| <tt><font size=+1>−m</font></tt> Expand and merge any <i>vac</i> archives that are found while reading |
| the input files. This option is useful for building an archive |
| from a collection of existing archives. Each archive is inserted |
| into the new archive as if it had been unpacked in the directory |
| in which it was found. Multiple archives can be unpacked in |
| |
| <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> |
| |
| a single directory and the contents will be merged. To be detected, |
| the archives must end in <tt><font size=+1>.vac</font></tt>. Note, an archive is inserted by |
| simply copying the root fingerprint and does not require the archive |
| to be unpacked.<br> |
| |
| </table> |
| <tt><font size=+1>−q</font></tt> Increase the performance of the <tt><font size=+1>−d</font></tt> option by detecting unchanged |
| files based on a match of the files name and other meta data, |
| rather than examining the contents of the files.<br> |
| <tt><font size=+1>−s</font></tt> Print out various statistics on standard error.<br> |
| <tt><font size=+1>−v</font></tt> Produce more verbose output on standard error, including the |
| name of the files added to the archive and the vac archives that |
| are expanded and merged.<br> |
| |
| </table> |
| <p><font size=+1><b>SOURCE </b></font><br> |
| |
| <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> |
| |
| <tt><font size=+1>/usr/local/plan9/src/cmd/vac<br> |
| </font></tt> |
| </table> |
| <p><font size=+1><b>SEE ALSO </b></font><br> |
| |
| <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> |
| |
| Plan 9’s <i>vacfs</i>(4) and <i>venti</i>(8)<br> |
| |
| </table> |
| |
| <td width=20> |
| <tr height=20><td> |
| </table> |
| <!-- TRAILER --> |
| <table border=0 cellpadding=0 cellspacing=0 width=100%> |
| <tr height=15><td width=10><td><td width=10> |
| <tr><td><td> |
| <center> |
| <a href="../../"><img src="../../dist/spaceglenda100.png" alt="Space Glenda" border=1></a> |
| </center> |
| </table> |
| <!-- TRAILER --> |
| </body></html> |
