Backing up disk with ext4 partitions

Thomas, welcome to these user forums.

Take a read of topic: 115378: Backup of Mint Linux is absurdly huge which may be of interest to you, in particular, see post #4 in this topic from Slava where this issue is shown to be a known issue to the development team, but there seems to be very little intention by Acronis to fix this as it doesn't appear to cause any problems when both creating a backup of a Linux EXT4 partition or in restoring the same.

Hi Steve, thanks for the response. I'll give it a shot anyways, but it is rather disappointing if I'm only able backup my ext4 partitions using sector-by-sector backup. It kind of defeats the purpose of using backup software in the first place, since I could just use something like dd for that. Not to mention that it's misleading of Acronis, since ext4 is advertised as a supported filesystem (and it works in previous versions... I use ATI 2013 at work and haven't had a problem with using it on ext4 partitions).

You may have corruption of your ext4 file system thus the errors.  Support for your file system does exist in the current product.

http://www.acronis.com/en-us/support/documentation/ATI2017/index.html#3…

Thomas, you would need to check the offline Acronis Logs from when you make the backup of your EXT4 partitions using the ATIH 2017 Rescue Media - this should give an indication if it does switch to using sector-by-sector mode.

It's been some months since I last tested this with my own Ubuntu system using the offline media so can't remember what the size of the backup was in relation to the size of the partition / used data on same.

Yeah I'll have to try and see what happens, though I assume it will revert to sector-by-sector backup since that's what the warning said it was doing.

Alright so it's definitely using sector-by-sector backup as an uncompressed backup is the exact same size as the partition. With compression the size of the backup is reasonable, but the drive is brand new so that's probably to be expected (and as I add and delete files, I don't know if it would stay that way...)

Thanks for your update Thomas confirming the sector-by-sector mode being used.  I am only a casual user of Linux so my actual usage is fairly low apart from one particular application that runs full time (World Community Grid) and which will be creating and deleting lots of temporary files.  I haven't noticed any significant increase in backup file sizes over the time I have been doing them though my partition sizes are fairly small too. 

It may be that Linux handles file fragmentation a whole lot better than Windows and reuses sectors more efficiently too.

I had a similar issue. I have two laptops, which both are dual-boot including Windows 10 and (a) Ubuntu / (b) Debian. While Acronis True Image Home 2012 was perfectly able to produce an image backup of my laptop with Windows 10 and Ubuntu (without sector-by-sector!), this was not the case with my similar other notebook containing Windows 10 and Debian. First I thought this was due to Debian. I therefore replaced Debian with Ubuntu. But still I received the message, that the ext4 partition would contain errors. But according to fsck this was not the case. Fiddling around with this for hours I finally found out that not every ext4 partition is the same: When making an ext4 file system, there are certain options to be defined. It seems that depending on these options Acronis will or will not be able to make an image backup of ext4 without the need for its sector-by-sector procedure. I found that the following command works when making an ext4 file system:

sudo mkfs.ext4 -b 4096 -E lazy_itable_init=0 -I 256 -i 16384 -O filetype,large_file,sparse_super,uninit_bg,^64bit,^metadata_csum /dev/sdb6

Obviously you'll have to replace the "/dev/sdb6" part with the partition name you want to format.

Certain other options may also work but I have only tried the above and had success with it.

Arne, thanks for sharing your findings about ATI and ext4 partition backups.  This is still an issue even with the latest ATI 2019 version as I found very recently when backing up a laptop just running Xubuntu 18.04 to an external drive which defaulted to sector by sector after telling me there were errors on the ext4 partition when fsck doesn't find any!

Yes, that is also what I found. My intention was not to say that it is not an issue anymore, but merely to share a work-around. If you create an ext4 formated partition with the mentioned mkfs.ext4 command Acronis should work without sector-by-sector mode (also for Xubuntu 18.04).

We both probably agree: It would be better, if one would not need that workaround and ext4 could be backed up in any scenario.

Arne, have bookmarked your work-around but will need to think about how to test this as don't really want to have to start over with a new install of my Linux boxes at present!  I have an old laptop that is a candidate for any testing albeit had to use forcepae --- forcepae on the install due to its age when I replaced Windows 7 on it with Xubuntu recently.  Had to use the same boot parameters when making the Linux version of the ATI 2019 rescue media to make a backup or else needed to use Clonezilla instead.

 Arne Lindemann wrote:

sudo mkfs.ext4 -b 4096 -E lazy_itable_init=0 -I 256 -i 16384 -O filetype,large_file,sparse_super,uninit_bg,^64bit,^metadata_csum /dev/sdb6

Obviously you'll have to replace the "/dev/sdb6" part with the partition name you want to format.

Certain other options may also work but I have only tried the above and had success with it.

Thanks very much for this. I used your parameters to set the correct filesystem features by booting from an Ubuntu live cd and setting the parameters with "tune2fs -O uninit_bg,^64bit,^metadata_csum /dev/sdb6" (these were (un)set by default). Beforehand you need to e2fsck the device. After (un)setting the filesystem features I had to run resize2fs. The command directs you to do this so it's pretty self-explanatory. For safety I made a backup using Clonezilla.

Afterwards I could backup using ATI 2019, showing the correct used size for the ext4 filesystems. The backup file was small and it finished quickly.

Regards,

Roelof.

Roelof, thanks for your further information.

I have been able to run the following sequence of commands after booting from my Xubuntu live USB stick and opening a terminal window.

sudo e2fsck -f /dev/sda2
sudo tune2fs -O uninit_bg,^64bit,^metadata_csum /dev/sda2
sudo resize2fs /dev/sda2

(repeated the above for /dev/sda1 too)

Then shutdown and booted normally into Xubuntu with no issues.  Not got round to booting from my ATI rescue media to test the difference this has made but look forward to not being told that there are partition errors because it is of my ext4 partitions!

Well, mixed results for me with this issue!

Making the changes for my main Xubuntu partition (/dev/sda1) worked fine with no errors reported by ATI 2019.

The same changes for my spare ext4 partition with only around 7GB of backup data didn't work and still gave errors which triggered sector by sector mode and a very large backup size.

I deleted the spare partition and recreated it as advised by Arne using:

sudo mkfs.ext4 -b 4096 -E lazy_itable_init=0 -I 256 -i 16384 -O filetype,large_file,sparse_super,uninit_bg,^64bit,^metadata_csum /dev/sda2

but even with this as an empty ext4 partition, it gave errors still and used sector by sector mode!

Last update: unmounted the sda2 partition and reformatted to FAT32 then repeated ATI 2019 backup and all completed successfully and quickly with no errors & not using sector by sector to give a backup of both my sda1 ext4 partition with my sda2 FAT32 partition!

One further test performed.  Used Gparted to reformat the FAT32 sda2 partition to ext3 then booted from my ATI 2019 (Linux) rescue media and made a full disk backup without any errors with a size of just 6.4GB (versus 81.8GB yesterday with sda2 as ext4 & falling over to sector by sector).

Definitely an issue with the ATI rescue media handling of ext4 partitions!

I currently facing the same issue in Acronis Snap Deploy 5 U3 1761 and 1808.

Unfortunately, none of the fixes so far have worked for me. Either creating the partition with Arne's options or changing them after install with Roelof's commands in a live boot environment.

We have an enterprise support contract with Acronis and I've escalated a support case with Acronis. Will let you guys know what I hear back.

Sorry to repost to an old thread, but this issue is fixed for us now in the newest build of Acronis Snap Deploy 5 Update 4 Build 1924.

Support told us about this fix and I can verify I don't need any of workarounds to capture an EXT4 partition any longer. Not sure if the fix was also ported to other Acronis products.

nvdev wrote:

Sorry to repost to an old thread, but this issue is fixed for us now in the newest build of Acronis Snap Deploy 5 Update 4 Build 1924.

Support told us about this fix and I can verify I don't need any of workarounds to capture an EXT4 partition any longer. Not sure if the fix was also ported to other Acronis products.

Hi! Thank you for sharing your experience! 
I've clarified - fix for EXT4 wasn't added to the bootable media of Acronis True Image yet, but the issue is known to developers.

Was it fixed in Acronis True Image 2020?

Alexey, welcome to these public User Forums.

Yes, as far as I am aware.

Steve Smith wrote:

Alexey, welcome to these public User Forums.

Yes, as far as I am aware.

Acronis True Image 2020 my ubuntu 22.04, the main EXT4 partition with a size of 15gb sees as 465 gb. need more than 3 hours

Valentin, please check that you are using the latest / final build version of ATI 2020 which is build #38600.

If you are using the Acronis bootable rescue media, then you should also make sure that this too is created using the latest build version or downloaded from your Acronis Account as the latest .ISO file.

If you still see a problem, then see forum topic: EXT4 partition backup (Linux).

Steve Smith wrote:

Valentin, please check that you are using the latest / final build version of ATI 2020 which is build #38600.

If you are using the Acronis bootable rescue media, then you should also make sure that this too is created using the latest build version or downloaded from your Acronis Account as the latest .ISO file.

If you still see a problem, then see forum topic: EXT4 partition backup (Linux).

 

The problem is solved, it turned out I have Ext4 + LVM

Valentin, thank you for sharing the answer to your issue here!