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mongodbrecoverydata-recoveryext4wiredtiger

Deleted a Mongodb data folder by accident on ext4, how to best recover data?

What's the best/fastest/safest way to recover deleted files from ext4 ?

Specs:

  • The disk is 1TB SSHD (hibrid HDD + SSD), also the partition is encrypted with LUKS Encryption (version 1)
  • Mongodb is using WiredTiger as a storage engine.

Also if I manage a partial recovery of files, could I do a partial recovery of mongo's collections?

Solution

  • Step 1: File recovery

    Fast Recovery of files using extundelete:

    sudo umount /path/to/disk && 
sudo extundelete /path/to/disk --restore-directory /path/to/dir -o /restored/path/
    • /path/to/disk represents the disk path, e.g. /dev/sdd , /dev/mapping/label
    • /path/to/dir represents the path that you want recovered relative to disk mounting point, e.g. if /dev/ssd would be mounted at /mnt/label/ the full path would be /mnt/label/path/to/dir and the relative path is /path/to/dir

    pros of recovery with extundelete:

    • it's lightweight
    • can work if the disk is mounted or encrypted
    • pretty fast, it gave answers if recovery is possible in seconds and it writes the recovered files with over 100 MB/s

    cons for data recovery in general

    • no guarantee for success
    • won't work if new data was written in the deleted sectors (so unmount the disk as soon as possible and make an image of the broken disk before any recovery)

    Step 2 : repair mongodb if missing data

    Backup before this step, mongod --repair could delete good data

    Untested, but from my understanding mongod --repair should help repair the database if incomplete otherwise you can continue recovery for WiredTiger with :