<p dir="ltr">The new data is written to the ORIGINAL lvm. At that point, the old data is written to the snapshot lvm. The snapshot lvm is initially of zero real size, no disk space is used. Only when blocks need to be written to in the original lvm are blocks written to in the snapshot. Thus drive space used is double the size of the new data: one write to archive the old data in the snapshot and a second write to store the new data in the original lvm. Its a performance hit but an overall time saver. Think of the snapshot as nothing but hard links to physical extents until an extent changes.</p>
<div class="gmail_quote">On Jan 23, 2016 12:42 PM, "DJ-Pfulio" <<a href="mailto:djpfulio@jdpfu.com">djpfulio@jdpfu.com</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Concerning LVM backups.<br>
<br>
If all the change data is being written to the snapshot area, how does that get<br>
merged back into the main storage and main DB after we are done with backups?<br>
<br>
<br>
<br>
<br>
On 01/22/2016 02:40 PM, Jim Kinney wrote:<br>
> Slide deck is live on <a href="http://ale.org" rel="noreferrer" target="_blank">ale.org</a> in meeting announcement page.<br>
> On Fri, 2016-01-22 at 10:54 -0500, DJ-Pfulio wrote:<br>
>> Are there notes, the presentation, and/or video from last night?<br>
>> Sounds like the presentation and some notes could really be helpful<br>
>> based on the<br>
>> comments.<br>
>><br>
>> Sorry I missed it!<br>
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