Questions tagged [snapshot]

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22
votes
3answers
5k views

Practical limit on the number of btrfs snapshots?

I am considering using btrfs on my data drive so that I can use snapper, or something like snapper, to take time based snapshots. I believe this will let me browse old versions of my data. This would ...
18
votes
1answer
25k views

How to take snapshot of an ext4 filesystem

Is there any way we can take a snapshot of an ext4 filesystem so that we can revert back to it later?
13
votes
1answer
5k views

GNU/Linux: overlay block device / stackable block device

GNU/Linux has union mount that overlays dirs. So you can mount a writeable dir on top of a read-only dir. When the writeable dir is unmounted the read-only dir is untouched. I am looking for the same ...
13
votes
1answer
12k views

ZFS Snapshot to file as Backup with rotation

I have a local FreeNAS system and want to use ZFS snapshots for backups. FreeNAS has the built-in Replication Tasks which use zfs send snapshot_name to send a snapshot to a remote system. But this ...
11
votes
5answers
29k views

Creating a snapshot of a linux system

I want to do the following - Save the current state of my linux OS(centOS6.5). Do some changes (more specifically inject a fault and test some service to check how it behaves when that particular type ...
11
votes
4answers
12k views

`cp -al` snapshot whose hard links get directed to a new file when edited

I am trying to take snapshots of a massive folder regularly. I have read here: http://www.mikerubel.org/computers/rsync_snapshots/#Incremental that cp -al takes a snapshot of a folder by simply ...
9
votes
1answer
771 views

Do LVM snapshots ultimately cause fragmentation?

I'm planning on using LVM in order to be able to take atomic snapshots of large files and rsync them to a remote site. What I'd like to know is whether there is any long-term impact on the main (non-...
9
votes
2answers
332 views

Rolling back btrfs subvolume with child subvolumes

Is there a canonical way of rolling back to a subvolume snapshot that has child subvolumes. So for example, this is my btrfs volume layout: ID 257 gen 59802 top level 5 path __active ID 258 gen 59784 ...
8
votes
2answers
11k views

How to delete btrfs subvolumes with <FS_TREE> in their name

I have a bunch of btrfs snapshots like so: 20:17:37 [root@galaxy /]$ btrfs subvolume list -a / |grep apt ID 271 gen 348 top level 5 path <FS_TREE>/@apt-snapshot-2013-04-17_21:44:30 ID 272 gen ...
7
votes
3answers
3k views

Performing accurate snapshot and incremental backups to a remote server

I have a few Ubuntu (and potentially RHEL) servers I'd like to back up to a central backup server (via rsh/SSH). I'd like to do both snapshot and incremental backups. The goal is that if one of the ...
6
votes
1answer
2k views

taking snapshots of a BTRFS volume mounted with nodatacow?

I plan to create two subvolumes on a BTRFS-formatted spinning disk. I plan to mount one of those subvolumes with nodatacow so that I can efficiently store virtual machine images and database files ...
5
votes
1answer
1k views

Online remount btrfs of root filesystem with different subvolume (snapshot)

Let's say you have a btrfs root filesystem on an online system. You want to revert the filesystem to an earlier state, of which you have a snapshot: remount /dev/sdaX / -o remount,subvol=snapshots/Y ...
4
votes
4answers
12k views

How are filesystem snapshots different from simply making a copy of the files?

by doing this, # btrfs subvolume snapshot /mnt/1 /mnt/1/snapshot # tree /mnt/1 /mnt/1 ├── a ├── snapshot │ ├── a │ └── subv └── subv └── b 3 directories, 3 files We can create snapshot from ...
4
votes
3answers
7k views

Linux alternative to file history/shadow copies for internal backup?

I am looking for (good) backup alternatives to the time machine of MacOS/OS X devices or file history on Windows machines. Actually what I am looking for is closer to Windows' solution than to the ...
4
votes
2answers
866 views

LVM snapshots vs. filesystem

I have a Linux system (Opensuse leap, but it's not that important) installed on a logical volume (and the ext4 filesystem). I want to upgrade it to a newer version, but to be on the safe side, I want ...
4
votes
2answers
3k views

Btrfs snapshot to non-btrfs disk. Encryption, read acess

I want to try Btrfs. I've already found that you can make a snapshot of a live system but there are a few thing I haven't found answers for. Well, as I understand a snapshot basically a full copy in ...
4
votes
3answers
3k views

Deep freeze like software for Fedora

For one of my labs, I need to maintain consistent file systems. So, I do not want any changes written to the file system after the system is shutdown. Currently, I am maintaining an operating system ...
4
votes
3answers
4k views

Merge changes to upper filesystem to lower filesystem in Linux Overlay (OverlayFS) mount

I would like to be able to merge changes from the upper filesystem of an overlay mount to a lower filesystem. I am interested both online (i.e. merge while the overlay is mounted) and offline (...
4
votes
1answer
86 views

Can a user-defined “destroy-after” property be set on a ZFS snapshot?

I know that (almost) arbitrary user-created properties can be added to a ZFS dataset on FreeBSD. But if I take snapshots of a dataset (or pool), can I set a user-defined property on an individual ...
4
votes
1answer
4k views

ZFS on Linux send/receive resume on poor/bad ssh connection

I am using ZFS on Linux, and trying to setup remote replication. But I have bad ssh connection, and zfs send/receive over ssh restarts again. I know there is a issue on ZoL, but I don't know when it ...
4
votes
1answer
2k views

What privileges are needed to delete a read-only btrfs subvolume?

I want to delegate non-root user to delete read-only subvolumes (snapshots). What exactly capabilities/rights I need to grant, so that he can remove his own read-only snapshots? I've already ...
4
votes
1answer
770 views

Restore Btrfs snapshot from subdirectory to parent

I have a Btrfs partition which has a single subvolume at the top level (/root). It has subvol=root option in /etc/fstab. Every week, I take a readonly snapshot into /root/snapshots/... using: btrfs ...
4
votes
0answers
763 views

Compiling and running Snapper for Ubuntu

I am trying to get snapper working in my Mint 14. (The version from launchpad is old and not compatible with Ubuntu 12.10. The OpenSuSe's build project failed to build it, too). So I try my luck with ...
3
votes
1answer
365 views

Is it possible and how to merge identical files between different snapshots in a btrfs file system?

I regularly use btrfs's snapshot to backup the whole system, but it's redundant to have identical files between different snapshots. Commonly, for example, I took a snapshot of @ as @...
3
votes
1answer
7k views

Qcow2 snapshots - snapshot for disk vda unsupported for storage type raw

I am running a KVM server (Ubuntu 14.04) and would like to take snapshots of my guests. I was reading how about how to do that in this article. It seemed as if I should be able to take a snapshot of a ...
3
votes
1answer
456 views

Can you do a btrfs snapshot of a live system?

I am planning on giving btrfs a try soon, and what I want to know, and can't seem to find online is this: Can you do a btrfs snapshot on a running system if the snapshot is not just of some small ...
3
votes
1answer
1k views

Never ending “Run configure hook of core snap if present”

I am using Debian 9 with KDE Plasma for work and fun, I just wanted to install Krita graphics app. It became an opportunity to tryout new instalation system called "snap". So I installed snapd and ...
3
votes
1answer
435 views

btrfs snapshots without subvolumes?

I'm starting to use btrfs. I want to be able to snapshot certain directories but do not want to create sub-volumes. Is this possible?
3
votes
2answers
834 views

LVM Snapshot without copy-on-write

I've been experimenting with LVM and how I can use it for managing data on my NFS server. With everything that I've read about snapshots, I am still unsure about how they perform in real life. Why ...
3
votes
3answers
3k views

Temporary restore LVM snapshot of root

I have a snapshot of the root filesystem that I want to boot with - bring the machine into a state it was a few days ago, run some tests and then go back to where I am right now. I tried editing ...
3
votes
1answer
1k views

LVM snapshot - performance for write-only data

I have a client that is archiving write-only , time-series data in a database (ie. data is rarely modified after it is written, and it is rarely read as it is on a secondary/backup/failover node). I ...
3
votes
1answer
2k views

How to configure AppArmor so that KVM can start guest that has a backing file chain

I'm playing around with using Qemu external snapshots for KVM (because they are so fast!) on Ubuntu 16.04 and have the following setup: All files for the VM are within a single directory (named after ...
3
votes
1answer
2k views

btrfs revert snapshot of root FS

Before upgrading to Fedora 25 I did a btrfs subvolume snapshot / /f24. I hat to little free space, so the update failed. Now the question is, how to revert the snapshot? I already booted into the ...
3
votes
1answer
76 views

How to copy multiple snapshots at once without duplicating data?

I have a live btrfs filesystem of 3.7TiB that's >90% full including old snapshots and a fresh 4TB backup harddisk. How to copy all existing snapshots to the backup harddisk? I tried # btrfs send ...
3
votes
1answer
3k views

How much can the space allocated for an LVM snapshot be reduced?

I created an LVM snapshot, then I modified the original logical volume, and now I see that I probably allocated too much space to hold the snapshot. And I want to reclaim some free space by reducing ...
3
votes
1answer
2k views

KVM - live external snapshots and appropriate disk names

If I wish to take an external snapshot of a running KVM guest, I would run a command like below: # create the directory for the snapshot data mkdir /vms/$DOMAIN/snapshots/$SNAPSHOT_NAME # create the ...
3
votes
3answers
4k views

Difference between fsfreeze and lvm snapshot

I heard recently about fsfreeze and I'm very interested in making snapshots of my VM with VMware and get a consistent state of disk using quiescence. All my file-systems are LVM volumes, and man ...
3
votes
2answers
1k views

How can I capture a consistent snapshot of a directory and all its children?

We have an application that periodically backs itself up to a directory on the local file system. Inside this directory are several more files and directories. I want to produce a "snapshot" of all ...
3
votes
1answer
639 views

Snapshot large changing files

At home I have the following backup scheme: All machines daily rsync to the servers $FULL_COPY directory. The server takes snapshots of that directory daily (also weekly/monthly), keeping at most X ...
3
votes
0answers
161 views

Revert to snapshot at boot

Can I take a snapshot of a physical machine and revert to that stage every time the machine boots? This can be done with virtual machines, but I want to do it for a physical machine. Background I ...
3
votes
0answers
714 views

How can I mount a VDI with snapshot?

Working on Linux Mint 18.1, VirtualBox 5.0.40_Ubuntu. I have a VDI file from a VirtualBox VM: ~/VirtualBox\ VMs/Win10x64/Win10x64.vdi I've taken a Snapshot: ~/VirtualBox\ VMs/Win10x64/Snapshots/{...
3
votes
1answer
587 views

Snapper to only take snapshots if something has changed, or at a lower cadence

I'm using snapper for automatic timeline snapshots of my filesystem. The issue I have is that it continues to take hourly snapshots even when nothing on the filesystem has changed, which causes the ...
3
votes
0answers
317 views

LXC with both GUI apps and snapshots on unmodified Fedora kernel

I am looking for a tool or library to run LXC that supports: running X applications conveniently snapshotting root filesystems (using a Fedora system with an unmodified kernel), so that I don't have ...
3
votes
1answer
474 views

Having trouble with LVM snapshot

I have a funtoo linux machine which I am trying to add ubuntu to (thats a whole other issue). It is encrypted with luks and has lvm on top of that. I have a 2 TB harddrive (sdb) which I would like ...
3
votes
1answer
507 views

Create Logical Volume Snapshot at boot and before mount

I'm using Kubuntu 11.10 and before I upgrade to 12.04, I want to make snapshots of my filesystems. Coming to think of that, I realized that it can be very useful to create snapshots of logical volumes ...
3
votes
1answer
244 views

How to test if two btrfs snapshots are identical or not?

As far as I know, in order to determine if a snapshot is identical with another one or not, we should check if Received UUID of destination is equal to UUID of source snapshot or not. But this time, ...
2
votes
3answers
3k views

Unable to zfs send | zfs receive datasets in same zpool

I have two environments Staging (staging) and Development (choang). I am unable to replicate (including snapshots) from dataset zfs/staging.assets to another dataset zfs/choang.assets within the same ...
2
votes
1answer
287 views

Restore single files from a btrfs snapshot without doing a full copy

Background I maintain a series of hourly snapshots on my btrfs filesystem using btrbk. The subvolume and snapshots are stored like this (names shortened to make it easier to follow): /@vol ...
2
votes
1answer
253 views

Will writing identical data to blocks of a file under ZFS use space in snapshots?

I have a 16M file. I take a snapshot of the ZFS filesystem which contains it. If I overwrite the file with the same data, will ZFS need to store two copies of all of the blocks of the file?
2
votes
1answer
696 views

How to change snap user directory?

I use Fedora. I wonder how I can configure snap to store all snapshots not in ~/snap/... but rather in ~/X/snap/... Sorry, I have already tried looking at various documentation of snapd but could ...