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<p class="MsoNormal"><span style="color:#1F497D">Thanks for pointing to the article. I have been following the article all the way. What intrigues me is the dht values associated with sub directories.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal">[root@glusterhackervm3 glus]# getfattr -n trusted.glusterfs.dht -e hex /brick2/vol<o:p></o:p></p>
<p class="MsoNormal">getfattr: Removing leading '/' from absolute path names<o:p></o:p></p>
<p class="MsoNormal"># file: brick2/vol<o:p></o:p></p>
<p class="MsoNormal">trusted.glusterfs.dht=0x00000001000000007ffffde2ffffffff
<o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D">
<o:p></o:p></span></p>
<p class="MsoNormal">[root@glusterhackervm3 glus]# getfattr -n trusted.glusterfs.dht -e hex /brick2/vol/d/<o:p></o:p></p>
<p class="MsoNormal">getfattr: Removing leading '/' from absolute path names<o:p></o:p></p>
<p class="MsoNormal"># file: brick2/vol/d/<o:p></o:p></p>
<p class="MsoNormal">trusted.glusterfs.dht=0x0000000100000000000000007ffffffe<o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Does it mean that only files whose DHT value ranges from
</span>0x00 to<span style="color:#1F497D"> 0x</span>7ffffffe <span style="color:#1F497D">
can be saved inside the ‘d’ directory. But then it provides a very narrow range of
</span>0x7ffffde2 to <span style="color:#1F497D"> 0x</span>7ffffffe to be created in that directory.
<o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Thanks and Regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Ram<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext"> gluster-users-bounces@gluster.org [mailto:gluster-users-bounces@gluster.org]
<b>On Behalf Of </b>Joe Julian<br>
<b>Sent:</b> Tuesday, November 08, 2016 2:06 PM<br>
<b>To:</b> gluster-users@gluster.org<br>
<b>Subject:</b> Re: [Gluster-users] understanding dht value<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p>Here's an article explaining how dht works. The hash maps are per-directory.<o:p></o:p></p>
<p><a href="https://joejulian.name/blog/dht-misses-are-expensive/">https://joejulian.name/blog/dht-misses-are-expensive/</a><o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">On 11/08/2016 11:04 AM, Ankireddypalle Reddy wrote:<o:p></o:p></p>
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<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<p class="MsoNormal">Hi,<o:p></o:p></p>
<p class="MsoNormal"> I am trying to make sense of the hash values that get assigned/used by DHT.<o:p></o:p></p>
<p class="MsoNormal"> /brick1/vol and /brick2/vol are the directories that are being used as bricks in a distributed replicated volume.<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">[root@glusterhackervm3 glus]# getfattr -n trusted.glusterfs.dht -e hex /brick1/vol<o:p></o:p></p>
<p class="MsoNormal">getfattr: Removing leading '/' from absolute path names<o:p></o:p></p>
<p class="MsoNormal"># file: brick1/vol<o:p></o:p></p>
<p class="MsoNormal">trusted.glusterfs.dht=0x0000000100000000000000007ffffde1<o:p></o:p></p>
<p class="MsoNormal">This means that any file gets hashed to a value from 0x00 to 0x7ffffde1 gets stored on this brick.<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">[root@glusterhackervm3 glus]# getfattr -n trusted.glusterfs.dht -e hex /brick2/vol<o:p></o:p></p>
<p class="MsoNormal">getfattr: Removing leading '/' from absolute path names<o:p></o:p></p>
<p class="MsoNormal"># file: brick2/vol<o:p></o:p></p>
<p class="MsoNormal">trusted.glusterfs.dht=0x00000001000000007ffffde2ffffffff
<o:p></o:p></p>
<p class="MsoNormal">This means that any file that’s hashed to a value from 0x7ffffde2 to 0xffffffff gets stored on this brick.<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">What is confusing is the dht values that are shown for the directories inside these brick directories. What do the dht values associated with the sub directories signify.<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">[root@glusterhackervm3 glus]# getfattr -n trusted.glusterfs.dht -e hex /brick2/vol/d/<o:p></o:p></p>
<p class="MsoNormal">getfattr: Removing leading '/' from absolute path names<o:p></o:p></p>
<p class="MsoNormal"># file: brick2/vol/d/<o:p></o:p></p>
<p class="MsoNormal">trusted.glusterfs.dht=0x0000000100000000000000007ffffffe<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">[root@glusterhackervm3 glus]# getfattr -n trusted.glusterfs.dht -e hex /brick2/vol/d/e<o:p></o:p></p>
<p class="MsoNormal">getfattr: Removing leading '/' from absolute path names<o:p></o:p></p>
<p class="MsoNormal"># file: brick2/vol/d/e<o:p></o:p></p>
<p class="MsoNormal">trusted.glusterfs.dht=0x0000000100000000000000007ffffffe<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">[root@glusterhackervm3 glus]# getfattr -n trusted.glusterfs.dht -e hex /brick2/vol/d/f<o:p></o:p></p>
<p class="MsoNormal">getfattr: Removing leading '/' from absolute path names<o:p></o:p></p>
<p class="MsoNormal"># file: brick2/vol/d/f<o:p></o:p></p>
<p class="MsoNormal">trusted.glusterfs.dht=0x00000001000000007fffffffffffffff<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">Thanks and Regards,<o:p></o:p></p>
<p class="MsoNormal">Ram<o:p></o:p></p>
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