erasetup is utility used to setup volumes and manage snapshots for dm-era
Usage:
erasetup [-h|--help] [-v|--verbose] [-f|--force]
<command> [command options]
create <name> <metadata-dev> <data-dev> [chunk-size]
open <name> <metadata-dev> <data-dev>
close <name>
status [name]
dumpmeta <metadata-dev>
takesnap <name> <snapshot-dev>
dropsnap <snapshot-dev>
dumpsnap <metadata-dev>
Create device example:
# lvcreate -L 32M -n meta vg
Logical volume "meta" created.
# lvcreate -L 4G -n data vg
Logical volume "data" created.
# erasetup create home /dev/vg/meta /dev/vg/data
# erasetup status
name: home
current era: 1
device size: 4.00 GiB
chunk size: 64.00 KiB
metadata size: 32.00 MiB
metadata used: 300.00 KiB (0.92%)
uuid: ERA-253-2
# mkfs.ext4 -q /dev/mapper/home
# mount /dev/mapper/home /home
Close device example
# erasetup close home
Open device example
# erasetup open home /dev/vg/meta /dev/vg/data
Take snapshot example:
# lvcreate -L 1G -n snap vg
Logical volume "snap" created.
# erasetup takesnap home /dev/vg/snap
# dd if=/dev/zero of=/home/test bs=1M count=100
100+0 records in
100+0 records out
104857600 bytes (105 MB) copied, 0.0889242 s, 1.2 GB/s
# erasetup status
name: home
current era: 3
device size: 4.00 GiB
chunk size: 64.00 KiB
metadata size: 32.00 MiB
metadata used: 300.00 KiB (0.92%)
uuid: ERA-253-2
snapshot: 45c62c3e66-8b2d-880d-ef53-48138498b3
status: Active
size: 1023.74 MiB
used: 100.11 MiB (9.78%)
era: 2
Drop snapshot example
# erasetup dropsnap /dev/vg/snap
# erasetup status
name: home
current era: 3
device size: 4.00 GiB
chunk size: 64.00 KiB
metadata size: 32.00 MiB
metadata used: 300.00 KiB (0.92%)
uuid: ERA-253-2
Dump snapshot example
# erasetup dumpsnap /dev/vg/snap
<snapshot block_size="128" blocks="65536" era="12"
dev="/dev/mapper/era-snap-45c62c3e66-8b2d-880d-ef53-48138498b3">
<block block="0" era="12"/>
<range begin="1" end="31" era="1"/>
<range begin="32" end="34" era="3"/>
<range begin="35" end="545" era="1"/>
<block block="546" era="3"/>
<range begin="547" end="2047" era="0"/>
<block block="2048" era="1"/>
<range begin="2049" end="2111" era="0"/>
<range begin="2112" end="3711" era="3"/>
<range begin="3712" end="6143" era="0"/>
<block block="6144" era="1"/>
<range begin="6145" end="10239" era="0"/>
<block block="10240" era="1"/>
<range begin="10241" end="14335" era="0"/>
<block block="14336" era="1"/>
<range begin="14337" end="18431" era="0"/>
<block block="18432" era="1"/>
<range begin="18433" end="30719" era="0"/>
<block block="30720" era="4"/>
<block block="30721" era="3"/>
<range begin="30722" end="32768" era="1"/>
<block block="32769" era="0"/>
<range begin="32770" end="33281" era="1"/>
<range begin="33282" end="51199" era="0"/>
<block block="51200" era="1"/>
<range begin="51201" end="55295" era="0"/>
<block block="55296" era="1"/>
<range begin="55297" end="65534" era="0"/>
<block block="65535" era="1"/>
</snapshot>