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Support sparsefiles Copy in blockfile snapshotter
Adds the ability to copy sparse files and can be configured in the config.
In the Go language, io.Copy is equivalent to cp --sparse=never xxx, so even if the initial scratch file is a sparse file, it is still a non-sparse file after go io.copy. Each snapshot block file will occupy the full block file size by default.
Hi @zhaojizhuang. Thanks for your PR.
I'm waiting for a containerd member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.
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Can we stat each file after the copy to see if the block usage differs? The expectation right now is blockfile snapshotter is not very efficient when copy file range is not used. Are the sparse file properties preserved when it doesn't go through a full read/write copy of the file?
@dmcgowan according to https://wiki.archlinux.org/title/sparse_file
We use the command "fallocate -d copy.img" to make the snapshot blockfile sparse.
here is the test demo,using nginxt,which has 7 layers
root@n37-006-180:~# nerdctl pull nginx --snapshotter blockfile
docker.io/library/nginx:latest: resolved |++++++++++++++++++++++++++++++++++++++|
index-sha256:32e76d4f34f80e479964a0fbd4c5b4f6967b5322c8d004e9cf0cb81c93510766: exists |++++++++++++++++++++++++++++++++++++++|
manifest-sha256:43df308e3a5e165fd5d4e077c991ed936aebca01bf20ab25961d7e542db410a0: exists |++++++++++++++++++++++++++++++++++++++|
config-sha256:1d668e06f1e534ab338404ba891c37d618dd53c9073dcdd4ebde82aa7643f83f: exists |++++++++++++++++++++++++++++++++++++++|
layer-sha256:e58cbd904f7f72cc6e30b30dc19b47fc4c1ee2a0103c69eb5b20f8e950c58e42: exists |++++++++++++++++++++++++++++++++++++++|
layer-sha256:b0a0cf830b12453b7e15359a804215a7bcccd3788e2bcecff2a03af64bbd4df7: exists |++++++++++++++++++++++++++++++++++++++|
layer-sha256:1e5314d67f1699f049bf4bd694833e1e2b1b35905847570442f75ca71e758a62: exists |++++++++++++++++++++++++++++++++++++++|
layer-sha256:4d84de5fb9b2d32bc417c2e043fcc88e3303970c61cd4916956e66431a9ce7d3: exists |++++++++++++++++++++++++++++++++++++++|
layer-sha256:05f7109fea9eb1af4aae06cbc0894f5e2c5b07a638ebb509f0d88b6dfc948997: exists |++++++++++++++++++++++++++++++++++++++|
layer-sha256:2818b7b6a9db4d0901d74850cf1096f76fa22d8a7fad4d711710fbf6ab1b48d1: exists |++++++++++++++++++++++++++++++++++++++|
layer-sha256:8066e07ce4f22945d61fa9682f5ef843bb750a4829d3176009d383933c27eedd: exists |++++++++++++++++++++++++++++++++++++++|
elapsed: 3.7 s total: 0.0 B (0.0 B/s)
After
After 7 snapshots (18~24) were sparsified, the results are as follows:
du -h
root@n37-006-180:/var/lib/containerd/io.containerd.snapshotter.v1.blockfile/snapshots# du -h 18 19 20 21 22 23 24
86M 18
198M 19
198M 20
198M 21
198M 22
198M 23
198M 24
du -h --apparent-size
root@n37-006-180:/var/lib/containerd/io.containerd.snapshotter.v1.blockfile/snapshots# du -h --apparent-size 18 19 20 21 22 23 24
512M 18
512M 19
512M 20
512M 21
512M 22
512M 23
512M 24
stat
root@n37-006-180:/var/lib/containerd/io.containerd.snapshotter.v1.blockfile/snapshots# stat 18 19 20 21 22 23 24
File: 18
Size: 536870912 Blocks: 175208 IO Block: 4096 regular file
Device: fe01h/65025d Inode: 1835365 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2024-05-08 16:06:57.442605960 +0800
Modify: 2024-05-08 16:06:57.422605477 +0800
Change: 2024-05-08 16:06:57.422605477 +0800
Birth: -
File: 19
Size: 536870912 Blocks: 403536 IO Block: 4096 regular file
Device: fe01h/65025d Inode: 1835373 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2024-05-08 16:07:02.313723617 +0800
Modify: 2024-05-08 16:07:02.289723037 +0800
Change: 2024-05-08 16:07:02.289723037 +0800
Birth: -
File: 20
Size: 536870912 Blocks: 403496 IO Block: 4096 regular file
Device: fe01h/65025d Inode: 1835380 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2024-05-08 16:07:06.029813372 +0800
Modify: 2024-05-08 16:07:06.020813155 +0800
Change: 2024-05-08 16:07:06.020813155 +0800
Birth: -
File: 21
Size: 536870912 Blocks: 403496 IO Block: 4096 regular file
Device: fe01h/65025d Inode: 1835420 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2024-05-08 16:07:09.975908685 +0800
Modify: 2024-05-08 16:07:09.966908468 +0800
Change: 2024-05-08 16:07:09.966908468 +0800
Birth: -
File: 22
Size: 536870912 Blocks: 403496 IO Block: 4096 regular file
Device: fe01h/65025d Inode: 1835428 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2024-05-08 16:07:13.929004166 +0800
Modify: 2024-05-08 16:07:13.921003973 +0800
Change: 2024-05-08 16:07:13.921003973 +0800
Birth: -
File: 23
Size: 536870912 Blocks: 403496 IO Block: 4096 regular file
Device: fe01h/65025d Inode: 1835429 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2024-05-08 16:07:17.882099647 +0800
Modify: 2024-05-08 16:07:17.874099454 +0800
Change: 2024-05-08 16:07:17.874099454 +0800
Birth: -
File: 24
Size: 536870912 Blocks: 403496 IO Block: 4096 regular file
Device: fe01h/65025d Inode: 1835436 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2024-05-08 16:07:21.825194887 +0800
Modify: 2024-05-08 16:07:21.834195105 +0800
Change: 2024-05-08 16:07:21.834195105 +0800
Birth: -
before
before 7 snapshots (18~24) were sparsified, the results are as follows:
du -h
root@n37-006-180:/var/lib/containerd/io.containerd.snapshotter.v1.blockfile/snapshots# du -h 25 26 27 28 29 30 31
513M 25
513M 26
513M 27
513M 28
513M 29
513M 30
512M 31
du -h --apparent-size
root@n37-006-180:/var/lib/containerd/io.containerd.snapshotter.v1.blockfile/snapshots# du -h --apparent-size 25 26 27 28 29 30 31
512M 25
512M 26
512M 27
512M 28
512M 29
512M 30
512M 31
stat
root@n37-006-180:/var/lib/containerd/io.containerd.snapshotter.v1.blockfile/snapshots# stat 25 26 27 28 29 30 31
File: 25
Size: 536870912 Blocks: 1048584 IO Block: 4096 regular file
Device: fe01h/65025d Inode: 1835047 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2024-05-10 11:41:07.107070124 +0800
Modify: 2024-05-10 11:41:07.090069713 +0800
Change: 2024-05-10 11:41:07.090069713 +0800
Birth: -
File: 26
Size: 536870912 Blocks: 1048584 IO Block: 4096 regular file
Device: fe01h/65025d Inode: 1835048 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2024-05-10 11:41:11.804183768 +0800
Modify: 2024-05-10 11:41:11.786183332 +0800
Change: 2024-05-10 11:41:11.786183332 +0800
Birth: -
File: 27
Size: 536870912 Blocks: 1048584 IO Block: 4096 regular file
Device: fe01h/65025d Inode: 1835053 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2024-05-10 11:41:15.521273699 +0800
Modify: 2024-05-10 11:41:15.513273505 +0800
Change: 2024-05-10 11:41:15.513273505 +0800
Birth: -
File: 28
Size: 536870912 Blocks: 1048584 IO Block: 4096 regular file
Device: fe01h/65025d Inode: 1835056 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2024-05-10 11:41:19.467369176 +0800
Modify: 2024-05-10 11:41:19.459368982 +0800
Change: 2024-05-10 11:41:19.459368982 +0800
Birth: -
File: 29
Size: 536870912 Blocks: 1048584 IO Block: 4096 regular file
Device: fe01h/65025d Inode: 1835059 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2024-05-10 11:41:23.421464842 +0800
Modify: 2024-05-10 11:41:23.413464649 +0800
Change: 2024-05-10 11:41:23.413464649 +0800
Birth: -
File: 30
Size: 536870912 Blocks: 1048584 IO Block: 4096 regular file
Device: fe01h/65025d Inode: 1835103 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2024-05-10 11:41:27.374560482 +0800
Modify: 2024-05-10 11:41:27.367560313 +0800
Change: 2024-05-10 11:41:27.367560313 +0800
Birth: -
File: 31
Size: 536870912 Blocks: 1048576 IO Block: 4096 regular file
Device: fe01h/65025d Inode: 1835104 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2024-05-10 11:41:31.315655833 +0800
Modify: 2024-05-10 11:41:31.325656075 +0800
Change: 2024-05-10 11:41:31.325656075 +0800
Birth: -