https://blog.lazy-evaluation.net/deContents © 2025 <a href="mailto:dzu@member.fsf.org">Detlev Zundel</a> Sat, 08 Mar 2025 11:07:56 GMTNikola (getnikola.com)http://blogs.law.harvard.edu/tech/rsshttps://blog.lazy-evaluation.net/de/posts/linux/vm-snapshots.html?pk_campaign=feedDetlev Zundel<div><div style="text-align:center" class="imageblock" id="org48f4f01"> <div id="org4096851" class="figure"> <p><img src="https://blog.lazy-evaluation.net/de/images/virt-manager.png" alt="virt-manager.png" title="Virtual Machine Manager Logo" align="middle" width="300"> </p> </div> </div> <p> A while ago, as VirtualBox was loosing its attractiveness due to license changes, I converted my virtual machines to KVM ones managed by <a href="https://virt-manager.org/">virt-manager</a>. One of the features that I just love is the capability to take snapshots of the hard disks. As I do not know of an easy way to do this from the GUI, I simply use <a href="https://www.libvirt.org/manpages/virsh.html">virsh</a> which is part of the <a href="https://www.libvirt.org/index.html">libvirt core distribution</a>. Before trying something "dangerous", just take a snapshot. If the experiment was not successful, then it is just a simple command to undo all the latest changes. I learned to love this feature lately as I tried crazy stuff like converting a VMs hard disc from MBR to GPT partitioning and when I ended up in an unbootable system, I could simply revert to the previous snapshot. Having this feature available empowered me to try things that may break the system. </p> <p> This short blog post is just intended to show with real transcripts how this works from the command line. </p> <p><a href="https://blog.lazy-evaluation.net/de/posts/linux/vm-snapshots.html?pk_campaign=feed">Weiterlesen…</a> (2 min verbleiben zum Lesen)</p></div>https://blog.lazy-evaluation.net/de/posts/linux/vm-snapshots.htmlThu, 23 Nov 2023 22:03:03 GMThttps://blog.lazy-evaluation.net/de/posts/reclaiming-vm-space-virtualbox.html?pk_campaign=feedDetlev Zundel<div><img alt="Compress Image" class="align-center" src="https://blog.lazy-evaluation.net/images/compress.png" style="width: 300px;"> <p>Creating a virtual machine requires specifying the amount of space to allocate for the virtual hard disk as one of the first steps. Dreading the notorious "not enough disk space" message, one usually aims to be on the safe side and reserves a generous amount at this stage. If the assignment is done in a static fashion then the allocated space is immediately claimed from the underlying file system and one thus has to come up with a pretty good guess in order not to waste space. Thankfully most VM solutions allow dynamic allocations which can grow on demand limited only by an upper bound making this a very attractive choice.</p> <p>A newly created VM with such an dynamic disk image indeed starts out nice and space saving but over time the image will eventually take up all the committed underlying disk space even though the VM reports to use only a subset of it. Reflecting on why this is the case leads us to an elegant setup reclaiming unused storage space on the host system.</p> <p><a href="https://blog.lazy-evaluation.net/de/posts/reclaiming-vm-space-virtualbox.html?pk_campaign=feed">Weiterlesen…</a> (6 min verbleiben zum Lesen)</p></div>https://blog.lazy-evaluation.net/de/posts/reclaiming-vm-space-virtualbox.htmlMon, 20 Jan 2020 21:14:32 GMT