# cinder

Published articles for cinder.

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## Mount volumes and when not to mount volumes, that is the question

DevFeed: [Mount volumes and when not to mount volumes, that is the question](<https://devfeed.tech/articles/mount-volumes-and-when-not-to-mount-volumes-that-is-the-question-19768.md>)

Original publisher: [Read original article](<https://cloud.blog.csc.fi/2018/12/mount-volumes-and-when-not-to-mount.html>)

Author: Unknown (noreply@blogger.com)

Published: 2018-12-31T06:50:00Z

Content type: article

Language: en

Sources: [CSC - IT Center For Science - Cloud Team](<https://devfeed.tech/sources/csc-it-center-for-science-cloud-team.md>)

Topics: [mount](<https://devfeed.tech/topics/mount.md>), [Filesystems](<https://devfeed.tech/topics/filesystems.md>), [Linux](<https://devfeed.tech/topics/linux.md>), [Cloud](<https://devfeed.tech/topics/cloud.md>)

Tags: [cinder](<https://devfeed.tech/tags/cinder.md>), [cloud](<https://devfeed.tech/tags/cloud.md>), [cpouta](<https://devfeed.tech/tags/cpouta.md>), [filesystem](<https://devfeed.tech/tags/filesystem.md>), [fstab](<https://devfeed.tech/tags/fstab.md>), [image](<https://devfeed.tech/tags/image.md>), [linux](<https://devfeed.tech/tags/linux.md>), [maintenance](<https://devfeed.tech/tags/maintenance.md>), [mount](<https://devfeed.tech/tags/mount.md>), [openstack](<https://devfeed.tech/tags/openstack.md>), [pouta](<https://devfeed.tech/tags/pouta.md>), [server](<https://devfeed.tech/tags/server.md>), [storage](<https://devfeed.tech/tags/storage.md>), [systemd](<https://devfeed.tech/tags/systemd.md>), [volume](<https://devfeed.tech/tags/volume.md>), [volumes](<https://devfeed.tech/tags/volumes.md>)

### AI overview

This article explains how to mount block-device volumes in Linux instances and why relying on standard /etc/fstab entries can prevent an instance from booting when a volume is missing or differs after an image-based deployment. It recommends mount options such as nofail and discusses noauto.

### Source excerpt

Some background: As part of the CSC Pouta Cloud Openstack installation we provide the cinder service. This allows our customers to attach block devices to their instances. A common way to illustrate what this means is to say: ".. it's like attaching a USB drive to the instance. " - Some Openstack trainer After attaching the block devices one has to format it with a filesystem and mount it. The usual way to mount block devices (in most Linux based distributions I've seen, if you know other ways please comment below!) every time the server reboots is to put something like this into /etc/fstab: /dev/vdb1 /mnt ext4 defaults 0 0 All clear so far I hope. It mounts block device /dev/vdb to /mnt as filesystem ext4 with the defaults mount options and the last two fields (numbers) are about dumping and file system checks. (Sometimes it's wise to use UUID or LABEL and not /dev/vdb1 in case you have more than two volumes.) But what happens if disk with is not there anymore? Well, with the above fstab your instance will not boot into the operating system. You'll be stuck having to perhaps enter single user mode or attaching a volume and then rebooting and modifying fstab. Single user mode is probably OK sometimes (it's inconvenient and takes time). But let's say you took a snapshot of an instance in Openstack with the glance service. This creates an image of the root disk. If you then spawn a new instance with that image as a root disk it will still have that /dev/vdb1 in /etc/fstab. Hey ho, the new instance booted from the image will not boot. Here you could of course just create a new volume and attach it. But if you used UUID or LABEL in fstab then it wouldn't find those and also break! So what is the best(tm) way? By using some nice fstab mount options. For example nofail UUID=1c7fc2f-f9d9-4e01-8d0f-190f05416831 /mnt ext4 nofail,defaults 0 0 There's another mount option called "noauto". The difference is put quite nicely in this stackoverflow question which has a piece from