JP Vossen on 26 Apr 2016 21:13:10 -0700

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Re: [PLUG] disk image one-liner

Ahhh, so XFS only.  Very cool though, thanks.

On 04/26/2016 11:25 PM, Keith C. Perry wrote:

I'll give you 3 :)  All based on from the example provided at the bottom of the xfsdump man page.

Assuming I have a 100Gb file system with 14Gb in use mounted at /mnt/vm which is my "source", I could format and mount a 16Gb USB disk on /mnt/flash


xfsdump -J - /mnt/vm | xfsrestore -p 300 -J - /mnt/flash

This would perfectly image the /mnt/vm filesystem to /mnt/flash and show status every 300 seconds.

Only thing left to do is reinstall the boot sectors. :D

But wait, there's more!

XFS is designed to be able to dump live file systems so on a running system, so...

xfsdump -p 300 -J - / | lzop > /mnt/replication/sysvol.xfz

...would dump the root file system, run it though lzop compression and save the file in sysvol.xfz on /mnt/replication.  That location could be an external drive or some other location.  I usually SSHfs mount backup locations for this task when I'm on the same LAN.  If I am pushing data off-LAN or SSHfs isn't available I can always use regular SSH...

xfsdump -p 300 -J - / | lzop | ssh user@remote.server.ip "dd of=/mnt/replication/sysvol.xfz"

BTW, you can also use the xfsrestore program to interactively browse and restore individual files or directories from a compressed dump file :D

I should also say, that this really is file system imaging and not strictly disk imaging but it came up in the context where the terms could be used interchangeably.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
Keith C. Perry, MS E.E.
Owner, DAO Technologies LLC
(O) +1.215.525.4165 x2033
(M) +1.215.432.5167

----- Original Message -----
From: "JP Vossen" <>
To: "Philadelphia Linux User's Group Discussion List" <>
Sent: Tuesday, April 26, 2016 5:52:08 PM
Subject: [PLUG] disk image one-liner

Subject: Re: [PLUG] [plug-announce] TOMORROW - Tue, Apr 19, 2016:
PLUG North - "Linux Containers" by Jason Plum and Rich Freeman (*6:30
pm* at CoreDial in Blue Bell)

On 04/26/2016 12:07 PM, Keith C. Perry wrote:
So, even though I always start with 100Gb disk images when I move
the file system, it gets imaged onto the appropriate medium in at the
appropriate size with the same one-liner. It doesn't matter whether
its a 16Gb USB stick, 128Gb SSD or 1Tb encrypted VM container with
system and data volumes.

And that one-liner would be....what now?  Sounds quite interesting!  XFS
only or generic?

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