BTRFSFEB 2014

www.anubhaskar.name

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1.Btrfs - Introduction2.Btrfs Architecture3.Prototype Architecture4.Install Btrfs5.Create Btrfs Volume6.Online resizing of Btrfs7.Add/Remove devices from Btrfs volume8.Create Btrfs sub volumes9.Delete Btrfs sub volumes10.Create Btrfs snapshots11.Rollback Btrfs snapshots

AGENDA

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1.File system + Volume Manager2.Data integrity – File system checksum3.Snapshots and clones4.Send/receive snapshots5.Highly Scalable (Max vol size - 16EiB)6.Copy-on-write transactional model7.Background scrub process for finding and fixing errors on files with redundant copies

8.Based on B-tree data structure9.GPL licensed

BTRFS - INTRODUCTION

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BTRFS ARCHITECTURE

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sda sdesdcsdb

md0 md1

vg0

lv0 lv1 lv2

/usr /var/home

sda sdesdcsdb

Volume/sub-volume

/usr /var/homeFile Systems

Logical Volumes

Volume Group

Physical Volumes

Physical Disks

Physical Disks

Storage Volume

File systems (btrfs)

LVM Btrfs

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PROTOTYPE ARCHITECTURE

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server1Centos6

sda sddsdcsdb

For installing OSCentos 68GB disk

For Btrfs1GB Disks

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Install Btrfs user space tools# yum install btrfs-progs

Create btrfs control node# mknod /dev/btrfs-control c 10 234

INSTALL BTRFS

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Create a RAID1 btrfs volume# mkfs.btrfs -d raid1 -m raid1 /dev/sdb /dev/sdc

View btrfs volume details# btrfs filesystem show /dev/sdb

Mount btrfs volume# mkdir /mount1# mount /dev/sdb /mount1

View file system details# btrfs filesystem df /mount1

View the size difference reported by df command# df -h /mount1

Add files to the volume# echo “test1” > /mount1/testfile1# ls -l /mount1

CREATE BTRFS VOLUME

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Shrink btrfs volumes online# df -h /mount1# btrfs filesystem resize -500m /mount1# df -h /mount1# ls -l /mount1# cat /mount1/testfile1

Expand btrfs volume online# df -h mount1# btrfs filesystem resize +250m /mount1# df -h mount1# btrfs filesystem resize max /mount1# df -h mount1# ls -l /mount1# cat /mount1/testfile1

ONLINE RESIZING OF BTRFS

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Add a new device to btrfs volume# btrfs filesystem show /dev/sdb# btrfs device add /dev/sdd /mount1# btrfs filesystem show /dev/sdb

Mirror metadata and data to new device# btrfs filesystem balance /mount1# btrfs filesystem show /dev/sdb# ls -l /mount1# cat /mount1/testfile1

Remove a device from btrfs volume# btrfs device delete /dev/sdd /mount1# btrfs filesystem show /dev/sdb

Wait for 5min and issue above command again to see some device missing error message disappearing.

ADD/REMOVE DEVICES FROM BTRFS VOLUME

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List subvolumes# cd /mount1# btrfs subvolume list /mount1# ls -l /mount1

Create a subvolume# btrfs subvolume create subvol1# btrfs subvolume list /mount1# ls -l /mount1

Create two more subvolumes# btrfs subvolume create subvol2# btrfs subvolume create subvol3# btrfs subvolume list /mount1#ls -l mount1

Mount subvol in a seperate directory# mkdir /mount2# mount -o subvol=subvol1 /dev/sdb /mount2# df -h /mount*

CREATE BTRFS SUB-VOLUMES

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Create a file in subvol1# echo “test2” > /mount2/testfile2# ls -l /mount2# ls -l /mount1/subvol1# cat /mount2/testfile2# cat /mount1/subvol1/testfile2# umount /mount2

Delete a subvolume# cd /mount1# btrfs subvolume delete subvol3# btrfs subvolume list /mount1# ls -l /mount1

DELETE BTRFS SUB-VOLUMES

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Add data to sub volume# echo “test3” > /mount1/subvol1/testfile3# ls -l /mount1/subvol1/# cat /mount1/subvol1/testfile3

Create a sub volume snapshot# btrfs subvolume list /mount1# btrfs subvolume snapshot /mount1/subvol1 /mount1/snapsubvol1# btrfs subvolume list /mount1# ls -l /mount1/snapsubvol1

Delete data from sub volume# rm /mount1/subvol1/testfile3# ls -l /mount1/subvol1/# ls -l /mount1/snapsubvol1

CREATE BTRFS SNAPSHOTS

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Rollback sub volume to snapshot# btrfs subvolume list /mount1# btrfs subvolume delete /mount1/subvol1# btrfs subvolume list /mount1# mv /mount1/snapsubvol1 /mount1/subvol1# btrfs subvolume list mount1

View data# ls -l /mount1/subvol1# cat /mount1/subvol1/testfile3

ROLLBACK BTRFS SNAPSHOTS

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THANK YOU

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