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... I am quite happy now with the performance of that new server I am |
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preparing. |
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See thread "Intel(R) C600 SAS Controller" for that story: |
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https://www.mail-archive.com/gentoo-user@l.g.o/msg146119.html |
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Right now I get quite good results when doing backups of the 2 existing |
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VMs (which have their virtio-disks on LVM-LVs on the host) ... up to |
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200MB/s ... I can show for reference, if someone is interested. |
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I think that is around the possible maximum. |
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---> |
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The issue I want to share with you is related to a btrfs subvol I have here. |
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Block device sda builds the btrfs-pool containing the root-fs: |
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# btrfs fi show |
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Label: ROOT uuid: 9133c469-df1e-45f5-a09f-d1b9c75c69da |
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Total devices 1 FS bytes used 29.47GiB |
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devid 1 size 500.00GiB used 278.04GiB path /dev/sda |
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Btrfs v3.12 |
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These are the subvolumes (I could/should rm some, but it doesn't matter |
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for this issue, afaik): |
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# btrfs su list / |
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ID 257 gen 4282 top level 5 path __active |
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ID 258 gen 4874 top level 5 path __active/root |
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ID 266 gen 4772 top level 258 path images |
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ID 267 gen 838 top level 258 path images/otrs |
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ID 289 gen 4285 top level 258 path images/windows |
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ID 538 gen 4874 top level 5 path __active/virt-backup |
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fstab has: |
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# grep btrfs /etc/fstab |
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LABEL=ROOT / btrfs defaults,noatime,compress=lzo 0 0 |
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LABEL=ROOT /mnt/virt-backup btrfs compress=no,noatime,subvolid=538 0 0 |
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... so I want to mount subvolid 538 with disabled compression (to speed |
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up backups as the files written to it are compressed on the fly via pigz |
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already). |
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But after booting I get that dir mounted with compress=lzo (which is |
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default). |
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# mount | grep btrfs |
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/dev/sda on / type btrfs (rw,noatime,compress=lzo,space_cache) |
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/dev/sda on /mnt/virt-backup type btrfs |
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(rw,noatime,compress=lzo,space_cache) |
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remounting works, though: |
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booze ~ # mount -o remount,compress=no /mnt/virt-backup/ |
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booze ~ # mount | grep btrfs |
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/dev/sda on / type btrfs (rw,noatime,space_cache) |
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/dev/sda on /mnt/virt-backup type btrfs (rw,noatime,space_cache) |
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BUT it remounts / without compression as well ... ! |
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Is it a bug? A mistake or misunderstanding? |
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Could someone test this on his gentoo-btrfs-box? |
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-- |
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Additional info: |
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# cat /proc/version |
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Linux version 3.12.21-gentoo-r1 ... |
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sys-fs/btrfs-progs-3.12-r1 |
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# btrfs su get-default / |
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ID 258 gen 4886 top level 5 path __active/root |
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# line in grub.cfg mounts default subvol (because no specific subvol is |
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specified) |
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linux /boot/vmlinuz-3.12.21-gentoo-r1 |
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root=UUID=9133c469-df1e-45f5-a09f-d1b9c75c69da ro |
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Thanks, regards, Stefan |
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