CODEWITHSUNDEEP
google-compute-engine
etrey
etrey

Reputation: 487

How do I make a snapshot of my boot disk?

I've read multiple times that I can cause read/write errors if I create a snapshot. Is it possible to create a snapshot of the disk my machine is booted off of?

Upvotes: 0

Views: 259

Answers (2)

Marilu
Marilu

Reputation: 983

You an use the GCE APIs. Use the Disks:insert API to create the Persistence disk. you have some code examples on how to start an instance using Python, but Google has libraries for other programming languages like Java, PHP and other

Upvotes: 0

DoubleD
DoubleD

Reputation: 56

It depends on what you mean by "snapshot".

A snapshot is not a backup, it is a way of temporarily capturing the state of a system so you can make changes test the results and revert back to the previously known good state if the changes cause issues. How to take a snapshot varies depending on the OS you're using, whether you're talking about a physical system or a virtual system, what virtualization platform, you're using, what image types you're using for disks within a given virtualization platform etc. etc. etc.

Once you have a snapshot, then you can make a real backup from the snapshot. You'll want to make sure that if it's a database server that you've flushed everything to disk and then write lock it for the time it takes to make the snapshot (typically seconds). For other systems you'll similarly need to address things in a way that ensures that you have a consistent state.

If you want to make a complete backup of your system drive, directly rather than via a snapshot then you want to shut down and boot off an alternate boot device like a CD or an external drive. If you don't do that, and try to directly back up a running system then you will be leaving yourself open to all manner of potential issues. It might work some of the time, but you won't know until you try and restore it.

If you can provide more details about the system in question, then you'll get more detailed answers.

As far as moving apps and data to different drives, data is easy provided you can shut down whatever is accessing the data. If it's a database, stop the database, move the data files, tell the database server where to find its files and start it up.

For applications, it depends. Often it doesn't matter and it's fine to leave it on the system disk. It comes down to how it's being installed.

It looks like that works a little differently. The first snapshot will create an entire copy of the disk and subsequent snapshots will act like ordinary snapshots. This means it might take a bit longer to do the first snapshot.

According to : this you ideally want to shut down the system before taking a snapshot of your boot disk. If you can't do that for whatever reason, then you want to minimize the amount of writes hitting the disk and then take the snapshot. Assuming you're using a journaling filesystem (ext3, ext4, xfs etc.) it should be able to recover without issue.

Upvotes: 3

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