207 lines
3.4 KiB
HTML
207 lines
3.4 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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<HTML
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><HEAD
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><TITLE
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>Backup program requirements</TITLE
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><META
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NAME="GENERATOR"
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CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK
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REL="HOME"
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TITLE="Autodir HOWTO"
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HREF="index.html"><LINK
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REL="PREVIOUS"
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TITLE="Backup support"
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HREF="backup.html"><LINK
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REL="NEXT"
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TITLE="Module options"
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HREF="x384.html"></HEAD
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><BODY
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CLASS="sect1"
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BGCOLOR="#FFFFFF"
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TEXT="#000000"
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LINK="#0000FF"
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VLINK="#840084"
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ALINK="#0000FF"
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><DIV
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CLASS="NAVHEADER"
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SUMMARY="Header navigation table"
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CELLSPACING="0"
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><TR
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><TH
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COLSPAN="3"
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ALIGN="center"
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>Autodir HOWTO</TH
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></TR
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><TR
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><TD
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WIDTH="10%"
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ALIGN="left"
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VALIGN="bottom"
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><A
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HREF="backup.html"
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ACCESSKEY="P"
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>Prev</A
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></TD
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><TD
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WIDTH="80%"
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ALIGN="center"
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VALIGN="bottom"
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><TD
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WIDTH="10%"
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ALIGN="right"
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VALIGN="bottom"
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HREF="x384.html"
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ACCESSKEY="N"
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>Next</A
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></TD
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></TR
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></TABLE
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><HR
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ALIGN="LEFT"
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WIDTH="100%"></DIV
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><DIV
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CLASS="sect1"
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><H1
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CLASS="sect1"
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><A
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NAME="backupreq"
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></A
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>12. Backup program requirements</H1
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><P
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><EM
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>Autodir</EM
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> demands some extra requirements from the backup program being used: when the backup is working on the <EM
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>real directory</EM
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>, with corresponding expired <EM
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>virtual directory</EM
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>, and that <EM
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>virtual directory</EM
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> is requested again by an application while the backup is running, the backup process is killed. First a <TT
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CLASS="literal"
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>SIGTERM</TT
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> is sent to gracefully stop it. But if it does not shut down in time - and it has one second to do this - a <TT
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CLASS="literal"
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>SIGKILL</TT
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> will be sent, which is guaranteed to stop the backup.</P
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><DIV
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CLASS="note"
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><P
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></P
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><TABLE
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CLASS="note"
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WIDTH="100%"
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BORDER="0"
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><TR
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><TD
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WIDTH="25"
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ALIGN="CENTER"
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VALIGN="TOP"
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><IMG
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SRC="../images/note.gif"
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HSPACE="5"
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ALT="Note"></TD
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><TD
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ALIGN="LEFT"
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VALIGN="TOP"
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>Only when the backup has stopped the application is given access to the requested <EM
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>virtual directory</EM
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>.</TD
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></TR
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></TABLE
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></DIV
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><DIV
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CLASS="important"
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><P
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></P
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><TABLE
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CLASS="important"
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WIDTH="100%"
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BORDER="0"
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><TR
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><TD
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WIDTH="25"
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ALIGN="CENTER"
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VALIGN="TOP"
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><IMG
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SRC="../images/important.gif"
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HSPACE="5"
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ALT="Important"></TD
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><TD
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ALIGN="LEFT"
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VALIGN="TOP"
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><P
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>Whatever backup is used, it should be able to recover from this signal gracefully, not causing unrecoverable side effects.</P
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></TD
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></TR
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></TABLE
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></DIV
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><P
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>One more important issue is the environment in which the backup runs. All backup programs run as root. But at the same time all unnecessary root privileges are taken away using POSIX capabilities. In other words these backup programs can read any file or directory that belongs to any user on the system and nothing more than that. Other than that, the backup process behaves like an ordinary user level process.</P
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></DIV
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><DIV
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CLASS="NAVFOOTER"
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><HR
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ALIGN="LEFT"
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WIDTH="100%"><TABLE
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SUMMARY="Footer navigation table"
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WIDTH="100%"
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BORDER="0"
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CELLPADDING="0"
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CELLSPACING="0"
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><TR
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><TD
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WIDTH="33%"
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ALIGN="left"
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VALIGN="top"
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><A
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HREF="backup.html"
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ACCESSKEY="P"
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>Prev</A
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></TD
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><TD
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WIDTH="34%"
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ALIGN="center"
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VALIGN="top"
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><A
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HREF="index.html"
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ACCESSKEY="H"
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>Home</A
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></TD
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><TD
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WIDTH="33%"
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ALIGN="right"
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VALIGN="top"
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><A
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HREF="x384.html"
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ACCESSKEY="N"
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>Next</A
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></TD
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></TR
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><TR
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><TD
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WIDTH="33%"
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ALIGN="left"
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VALIGN="top"
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>Backup support</TD
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><TD
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WIDTH="34%"
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ALIGN="center"
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VALIGN="top"
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> </TD
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><TD
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WIDTH="33%"
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ALIGN="right"
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VALIGN="top"
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>Module options</TD
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></TR
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></TABLE
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></DIV
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></BODY
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></HTML
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> |