#1 Global Leader in Data Resilience

Veeam Agent for Linux 6 blksnap module - Xen PV/PVHVM filesystem corruption

KB ID: 4428
Product: Veeam Agent for Linux | 6.0
Published: 2023-03-20
Last Modified: 2024-02-16
mailbox
Get weekly article updates
By subscribing, you are agreeing to have your personal information managed in accordance with the terms of Veeam's Privacy Notice.

Cheers for trusting us with the spot in your mailbox!

Now you’re less likely to miss what’s been brewing in our knowledge base with this weekly digest

error icon

Oops! Something went wrong.

Please, try again later.

Article Applicability

This article is relevant only if the answer to all three of these questions is "Yes."

  1. Is Veeam Agent for Linux 6 in use?
  2. Is Veeam Agent for Linux installed within a Xen PV/PVHVM virtual machine, specifically Citrix XenServer or XCP-ng?
  3. Is that virtual machine running one of these Linux distros?
    • RHEL/Oracle Linux 9
    • SLES 15 SP3+
    • openSUSE Tumbleweed/Leap 15.3+
    • Ubuntu 22.04+
    • Debian 11

Challenge

After Veeam Agent for Linux completes a volume-level backup or file-level backup using a snapshot, filesystem corruption is detected.

/var/log/syslog example:

EXT4-fs error (device dm-0): ext4_lookup:1752: inode #129793: comm ls: iget: checksum invalid
EXT4-fs error (device dm-0): ext4_lookup:1752: inode #129793: comm ls: iget: checksum invalid
EXT4-fs warning (device dm-0): ext4_dirblock_csum_verify:400: inode #12: comm ls: No space for directory leaf checksum. Please run e2fsck -D.
EXT4-fs error (device dm-0): htree_dirblock_to_tree:1042: inode #12: comm ls: Directory block failed checksum

 

Affected Configuration

Veeam Agent for Linux 6 is installed on a Xen PV/PVHVM virtual machine running a Linux distribution that uses blksnap kernel module by default (RHEL/Oracle Linux 9, SLES 15 SP3+,openSUSE Tumbleweed/Leap 15.3+,Ubuntu 22.04+, or Debian 11). For more information about which distributions use blksnap, refer to KB2804.

Cause

Research has determined that this issue is related xen-blkfront handling of read requests with the REQ_FUA bit enabled (implicitly converting these read requests to be zero-write requests, effectively zeroing the block being read).

For more information, refer to this Xenproject patch request: [PATCH] xen/blkfront: Only check REQ_FUA for writes

Solution

This issue is resolved in Veeam Agent for Linux 6.0.2.1173. To obtain it, contact Veeam Technical Support.

More Information

Veeam Agent for Linux User Guide — System Requirements

For virtual machines, only full virtualization type is supported. Oracle VM virtual machines are supported with limitations. Virtual I/O (VirtIO) devices have experimental support status. Other containers and paravirtualized instances are not supported and may result in corruption of the source file system — for more information, see this Veeam KB article.

To submit feedback regarding this article, please click this link: Send Article Feedback
To report a typo on this page, highlight the typo with your mouse and press CTRL + Enter.

Spelling error in text

This site is protected by hCaptcha and its Privacy Policy and Terms of Service apply except as noted in our Privacy Policy.
Thank you!

Thank you!

Your feedback has been received and will be reviewed.

Oops! Something went wrong.

Please, try again later.

You have selected too large block!

Please try select less.

KB Feedback/Suggestion

This form is only for KB Feedback/Suggestions, if you need help with the software open a support case

By submitting, you are agreeing to have your personal information managed in accordance with the terms of Veeam's Privacy Notice.
This site is protected by hCaptcha and its Privacy Policy and Terms of Service apply except as noted in our Privacy Policy.
Verify your email to continue your product download
We've sent a verification code to:
  • Incorrect verification code. Please try again.
An email with a verification code was just sent to
Didn't receive the code? Click to resend in sec
Didn't receive the code? Click to resend
Thank you!

Thank you!

Your feedback has been received and will be reviewed.

error icon

Oops! Something went wrong.

Please, try again later.