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List:       dragonfly-users
Subject:    Re: Hammer fileystem disk full problem
From:       Tim Darby <t+dfbsd () timdarby ! net>
Date:       2013-06-16 13:56:37
Message-ID: CAP3DVK+9b-fCU+Gs809R4XmxXmBcJ_tvaBX-s_gJ-Q3GJpjXig () mail ! gmail ! com
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On Sat, Jun 15, 2013 at 11:50 AM, Matthew Dillon <
dillon@apollo.backplane.com> wrote:

>
> :>     hammer reblock <fs> 90
> :>
> :>     Each PFS needs to be independently reblocked.
> :>
> :>                                         -Matt
> :>
> :Thanks, Matt!  After doing just the 10% on each PFS, I had recovered
> enough
> :space to get back in operation.  I read the man page, but I'm still not
> :clear on what exactly the fill percentage does?
>
>     Basically HAMMER1 doesn't keep track of free space on a block-by-block
>     basis.  It keeps track of free space on a segment (~2MB) by segment
>     basis and iterates through the segment until it fills up.  In order
>     to free space, the segment has to become 100% empty.
>
>     By default the reblocker will reblock out of all storage segments,
>     which can temporarily require more storage during the run until it
>     sorts things out.  This is desireable for normal operation because
>     it defragments the disk quite well.  But it doesn't work well if the
>     filesystem is completely full.
>
>     Telling the reblocker to only reblock out of storage segments that
>     are underutilized has a better chance of clearing those segments
>     out and freeing them up before the reblocker would otherwise run out
>     of space.  Once things get cleaned up enough there should be enough
>     free space to run the reblocker in normal mode.
>
>                                                 -Matt
>
> That makes sense, thanks again!

Tim

[Attachment #3 (text/html)]

<div dir="ltr"><div class="gmail_default" style="font-family:&#39;trebuchet \
ms&#39;,sans-serif;font-size:small"><span style="font-family:arial">On Sat, Jun 15, \
2013 at 11:50 AM, Matthew Dillon </span><span dir="ltr" \
style="font-family:arial">&lt;<a href="mailto:dillon@apollo.backplane.com" \
target="_blank">dillon@apollo.backplane.com</a>&gt;</span><span \
style="font-family:arial"> wrote:</span><br>

</div><div class="gmail_extra"><div class="gmail_quote"><blockquote \
class="gmail_quote" style="margin:0px 0px 0px \
0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><br>



> &gt;       hammer reblock &lt;fs&gt; 90<br>
<div class="im">:&gt;<br>
> &gt;       Each PFS needs to be independently reblocked.<br>
> &gt;<br>
> &gt;                                                             -Matt<br>
> &gt;<br>
> Thanks, Matt!   After doing just the 10% on each PFS, I had recovered enough<br>
> space to get back in operation.   I read the man page, but I&#39;m still not<br>
> clear on what exactly the fill percentage does?<br>
<br>
</div>      Basically HAMMER1 doesn&#39;t keep track of free space on a \
                block-by-block<br>
      basis.   It keeps track of free space on a segment (~2MB) by segment<br>
      basis and iterates through the segment until it fills up.   In order<br>
      to free space, the segment has to become 100% empty.<br>
<br>
      By default the reblocker will reblock out of all storage segments,<br>
      which can temporarily require more storage during the run until it<br>
      sorts things out.   This is desireable for normal operation because<br>
      it defragments the disk quite well.   But it doesn&#39;t work well if the<br>
      filesystem is completely full.<br>
<br>
      Telling the reblocker to only reblock out of storage segments that<br>
      are underutilized has a better chance of clearing those segments<br>
      out and freeing them up before the reblocker would otherwise run out<br>
      of space.   Once things get cleaned up enough there should be enough<br>
      free space to run the reblocker in normal mode.<br>
<br>
                                                                        -Matt<br>
<br>
</blockquote></div><div class="gmail_default" style="font-family:&#39;trebuchet \
ms&#39;,sans-serif">That makes sense, thanks again!</div><div \
class="gmail_extra"><div><div><br></div>Tim</div></div></div></div>



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