<div dir="ltr"><div>To avoid changes on the fly its possible to use snapshot.</div><div><br></div><div>I am wondering, what will happen if ill feed dd through gzip. Will it compress the empty spaces ?</div><br clear="all">
--------------------------------------------------<br>Michael Ben-Nes - Internet Consultant and Director.<br><a href="http://www.epoch.co.il">http://www.epoch.co.il</a> - weaving the Net.<br>Cellular: 054-4848113<br>--------------------------------------------------<br>
<br><br><div class="gmail_quote">On Thu, Dec 31, 2009 at 1:03 AM, Tzafrir Cohen <span dir="ltr"><<a href="mailto:tzafrir@cohens.org.il">tzafrir@cohens.org.il</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div class="im">On Thu, Dec 31, 2009 at 12:35:48AM +0200, sammy ominsky wrote:<br>
> On 31/12/2009, at 00:27, Hetz Ben Hamo wrote:<br>
><br>
> > doing the backup. dd is nice, but that will copy also the empty space<br>
> > (although it won't have impact on the size of the backup, it will have an<br>
> > impact on the time it takes).<br>
><br>
> dd has a --sparse flag which makes it not copy empty space.<br>
<br>
</div>I don't see such a flag in the man page.<br>
<br>
partimage avoids copying any "free" block (block marked as free by the<br>
file system). If that block also happens to be zeroed out, dd is not<br>
aware of such details. And frankly can't safely be aware of them if Hetz<br>
want to copy a mounted partition.<br>
<br>
Also note that if you use dd to copy a mounted partition, you copy<br>
different parts of it in different times. This is tricky at best. Unless<br>
you e.g. use an LVM with a snapshot.<br>
<br>
tar (or any other backup of files) is safer. Even there you don't get a<br>
complete snapshot of the system. But at least every file is valid.<br>
<font color="#888888"><br>
--<br>
Tzafrir Cohen | <a href="mailto:tzafrir@jabber.org">tzafrir@jabber.org</a> | VIM is<br>
<a href="http://tzafrir.org.il" target="_blank">http://tzafrir.org.il</a> | | a Mutt's<br>
<a href="mailto:tzafrir@cohens.org.il">tzafrir@cohens.org.il</a> | | best<br>
ICQ# 16849754 | | friend<br>
</font><div><div></div><div class="h5"><br>
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