Public bug reported: I experience this with Ubuntu 21.04. I've not tested on older releases. I have a btrfs RAID1 array and simulated a failed disk and then replaced it with the `btrfs replace` feature part of btrfs-progs after mounting the remaining disk with the degraded,noatime mount options.
For clarity: The disk that is being used in btrfs replace is sda1, sdb1 is the existing disk with the data that is mounted degraded. Unfortunately, when you begin the replacement, btrfs begins slowly allocating new empty single chunks on the disk that was mounted degraded (sdb1) as soon as the btrfs replace begins, seemingly equal to the amount of raid1 chunks that were already allocated + 1. As the replace continues, this value increases: Data,single: Size:107.00GiB, Used:5.25MiB (0.00%) /dev/sdb1 107.00GiB ... several minutes later as btrfs replace continues to run ... Data,single: Size:177.00GiB, Used:5.25MiB (0.00%) /dev/sdb1 177.00GiB I have also posted this on the Btrfs kernel mailing list here for more details and output from commands: https://lore.kernel.org/linux- btrfs/cafmvigfq+xotjo_578lvsvycd3sblcv_ap6a+b0u+ybapu2...@mail.gmail.com/T/#t It's speculated this could be an Ubuntu specific issue. What is certain is I've done this process three times with this array on Ubuntu 21.04 and it happens every time, so I can reproduce it 100%. I believe this is a bug with the Ubuntu kernel, but I suppose it could be related to btrfs-progs. What is certain is the btrfs replace triggers the issue. I'm happy to provide any more additional details as best I can. Thanks, -Jonah ** Affects: linux (Ubuntu) Importance: Undecided Status: Incomplete ** Tags: btrfs ** Description changed: I experience this with Ubuntu 21.04. I have a btrfs RAID1 array and simulated a failed disk and then replaced it with the `btrfs replace` feature part of btrfs-progs after mounting the remaining disk with the degraded,noatime mount options. + For clarity: The disk that is being used in btrfs replace is sda1, sdb1 + is the existing disk with the data that is mounted degraded. + Unfortunately, when you begin the replacement, btrfs begins slowly allocating new empty single chunks on the disk that was mounted degraded - as soon as the btrfs replace begins, seemingly equal to the amount of - raid1 chunks that were already allocated + 1. As the replace continues, - this value increases: + (sdb1) as soon as the btrfs replace begins, seemingly equal to the + amount of raid1 chunks that were already allocated + 1. As the replace + continues, this value increases: Data,single: Size:107.00GiB, Used:5.25MiB (0.00%) - /dev/sdb1 107.00GiB + /dev/sdb1 107.00GiB ... several minutes later as btrfs replace continues to run ... Data,single: Size:177.00GiB, Used:5.25MiB (0.00%) - /dev/sdb1 177.00GiB + /dev/sdb1 177.00GiB I have also posted this on the Btrfs kernel mailing list here for more details and output from commands: https://lore.kernel.org/linux- btrfs/cafmvigfq+xotjo_578lvsvycd3sblcv_ap6a+b0u+ybapu2...@mail.gmail.com/T/#t It's speculated this could be an Ubuntu specific issue. What is certain is I've done this process three times with this array on Ubuntu 21.04 and it happens every time, so I can reproduce it 100%. I believe this is a bug with the Ubuntu kernel, but I suppose it could be related to btrfs-progs. What is certain is the btrfs replace triggers the issue. I'm happy to provide any more additional details as best I can. Thanks, -Jonah ** Description changed: - I experience this with Ubuntu 21.04. I have a btrfs RAID1 array and - simulated a failed disk and then replaced it with the `btrfs replace` - feature part of btrfs-progs after mounting the remaining disk with the - degraded,noatime mount options. + I experience this with Ubuntu 21.04. I've not tested on older releases. + I have a btrfs RAID1 array and simulated a failed disk and then replaced + it with the `btrfs replace` feature part of btrfs-progs after mounting + the remaining disk with the degraded,noatime mount options. For clarity: The disk that is being used in btrfs replace is sda1, sdb1 is the existing disk with the data that is mounted degraded. Unfortunately, when you begin the replacement, btrfs begins slowly allocating new empty single chunks on the disk that was mounted degraded (sdb1) as soon as the btrfs replace begins, seemingly equal to the amount of raid1 chunks that were already allocated + 1. As the replace continues, this value increases: Data,single: Size:107.00GiB, Used:5.25MiB (0.00%) /dev/sdb1 107.00GiB ... several minutes later as btrfs replace continues to run ... Data,single: Size:177.00GiB, Used:5.25MiB (0.00%) /dev/sdb1 177.00GiB I have also posted this on the Btrfs kernel mailing list here for more details and output from commands: https://lore.kernel.org/linux- btrfs/cafmvigfq+xotjo_578lvsvycd3sblcv_ap6a+b0u+ybapu2...@mail.gmail.com/T/#t It's speculated this could be an Ubuntu specific issue. What is certain is I've done this process three times with this array on Ubuntu 21.04 and it happens every time, so I can reproduce it 100%. I believe this is a bug with the Ubuntu kernel, but I suppose it could be related to btrfs-progs. What is certain is the btrfs replace triggers the issue. I'm happy to provide any more additional details as best I can. Thanks, -Jonah -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1925284 Title: Btrfs: Disk replacement causes massive allocation of empty single chunks while degraded Status in linux package in Ubuntu: Incomplete Bug description: I experience this with Ubuntu 21.04. I've not tested on older releases. I have a btrfs RAID1 array and simulated a failed disk and then replaced it with the `btrfs replace` feature part of btrfs-progs after mounting the remaining disk with the degraded,noatime mount options. For clarity: The disk that is being used in btrfs replace is sda1, sdb1 is the existing disk with the data that is mounted degraded. Unfortunately, when you begin the replacement, btrfs begins slowly allocating new empty single chunks on the disk that was mounted degraded (sdb1) as soon as the btrfs replace begins, seemingly equal to the amount of raid1 chunks that were already allocated + 1. As the replace continues, this value increases: Data,single: Size:107.00GiB, Used:5.25MiB (0.00%) /dev/sdb1 107.00GiB ... several minutes later as btrfs replace continues to run ... Data,single: Size:177.00GiB, Used:5.25MiB (0.00%) /dev/sdb1 177.00GiB I have also posted this on the Btrfs kernel mailing list here for more details and output from commands: https://lore.kernel.org/linux- btrfs/cafmvigfq+xotjo_578lvsvycd3sblcv_ap6a+b0u+ybapu2...@mail.gmail.com/T/#t It's speculated this could be an Ubuntu specific issue. What is certain is I've done this process three times with this array on Ubuntu 21.04 and it happens every time, so I can reproduce it 100%. I believe this is a bug with the Ubuntu kernel, but I suppose it could be related to btrfs-progs. What is certain is the btrfs replace triggers the issue. I'm happy to provide any more additional details as best I can. Thanks, -Jonah To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1925284/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
