<p dir="ltr">I see your point. First snapshot _is_ complete. Second is only back to the first, etc. To continue with this, it would require flattening the snapshots after the copy. With only a single snapshot and assuming an hour or so of activity, that could be seconds. It could be several minutes in a high-write db.</p>
<p dir="ltr">I see array as being storage. I don't think mysql has direct disk access/control like Oracle. I'm 90% certain it requires an OS to manage a filesystem layer.</p>
<div class="gmail_extra"><br><div class="gmail_quote">On Nov 22, 2016 9:51 AM, "Lightner, Jeffrey" <<a href="mailto:JLightner@dsservices.com">JLightner@dsservices.com</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">The question says “array” which makes it sound like they’re NOT talking about LVM snapshot but rather native snapshotting within an external storage array (e.g.
Thin Image within Hitachi). Snapshots one has to be careful with because often they do not contain all the data from the original but only a subset with pointers back to the original and separate storage for deltas where the copy the original diverge over
time.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Also the original question didn’t say he wanted this for backup. It said the only results of a web search were thousands of cautioning about relying on snapshots
as a replacement for backups. It’s quite possible the question has another purpose in mind entirely (e.g. using a copy of a database for testing or reporting purposes).
<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> <a href="mailto:ale-bounces@ale.org" target="_blank">ale-bounces@ale.org</a> [mailto:<a href="mailto:ale-bounces@ale.org" target="_blank">ale-bounces@ale.org</a>]
<b>On Behalf Of </b>Jim Kinney<br>
<b>Sent:</b> Monday, November 21, 2016 4:39 PM<br>
<b>To:</b> Atlanta Linux Enthusiasts<br>
<b>Subject:</b> Re: [ale] MySQL array based snapshot<u></u><u></u></span></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">This sounds to me like a LVM snapshot of the database file space.<u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<div>
<p class="MsoNormal"><a href="http://devN" target="_blank">http://dev</a>.<a href="http://mysql.com/doc/refman/5.7/en/backup-methods.html" target="_blank">mysql.com/doc/<wbr>refman/5.7/en/backup-methods.<wbr>html</a><u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">Snapshot _IS_ a backup as long as it is copied off the original machine. Loud google mouths are not always accurate. Dump your Google search cookie and see what comes up again.<u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">There is a STUN event but it's pretty short. The key that I see is to lock the DB after a flush (see link) , make the LVM snapshot, then release the lock, copy out the snapshot as a backup. The performance drag happens during the copy of
the snapshot but the copy can be 'nice 20' if things are on a decent drive subsystem and drive failure is not expected to be eminent.<u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">On Mon, 2016-11-21 at 14:45 -0500, Chris Fowler wrote:<u></u><u></u></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:black">I've received this question today and I can't pinpoint on if MySQL supports it or not. Google is flooding me with "snapshot is not a backup" pages.<u></u><u></u></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:black"><u></u> <u></u></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:black">"Need Processor counts and if the internal DB supports array based snapshots which result in minimal STUN of the virtual disk."<u></u><u></u></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:black"><u></u> <u></u></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:black">I'm running MySQL 5.X.<u></u><u></u></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:black"><u></u> <u></u></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:black"><u></u> <u></u></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:black">Chris<u></u><u></u></span></p>
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</div>
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<pre>-- <u></u><u></u></pre>
<pre>James P. Kinney III<u></u><u></u></pre>
<pre><u></u> <u></u></pre>
<pre>Every time you stop a school, you will have to build a jail. What you<u></u><u></u></pre>
<pre>gain at one end you lose at the other. It's like feeding a dog on his<u></u><u></u></pre>
<pre>own tail. It won't fatten the dog.<u></u><u></u></pre>
<pre>- Speech 11/23/1900 Mark Twain<u></u><u></u></pre>
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