Create Bluestore OSD backed by SSD

Dont take my word for it on the WAL sizing – Check http://docs.ceph.com/docs/mimic/rados/configuration/bluestore-config-ref/

This script will create a spare 20G Logical volume to use as the WAL for a second spinner later if you need it

export SSD=sdc
export SPINNER=sda

vgcreate ceph-ssd-0 /dev/$SSD
vgcreate ceph-hdd-0 /dev/$SPINNER

lvcreate --size 20G -n block-0 ceph-hdd-0
lvcreate -l 100%FREE -n block-1 ceph-hdd-0

lvcreate --size 20G -n ssd-0 ceph-ssd-0
lvcreate --size 20G -n ssd-1 ceph-ssd-0
lvcreate -l 100%FREE -n ssd-2 ceph-ssd-0

ceph-volume lvm create --bluestore --data ceph-hdd-0/block-1 --block.db ceph-ssd-0/ssd-0
ceph-volume lvm create --bluestore --data ceph-ssd-0/ssd-2

KVM\Qemu\Openstack – Manage a live migration

virsh qemu-monitor-command {VMNAME} --pretty '{"execute":"migrate_cancel"}'

Allow Virsh more downtime(If it cant keepup with RAM utilization)

virsh migrate-setmaxdowntime VMNAME 2500

 

Check migration status

virsh domjobinfo instance-000002ac
Job type: Unbounded
Operation: Outgoing migration
Time elapsed: 1307956 ms
Data processed: 118.662 GiB
Data remaining: 9.203 MiB
Data total: 8.005 GiB
Memory processed: 118.662 GiB
Memory remaining: 9.203 MiB
Memory total: 8.005 GiB
Memory bandwidth: 41.294 MiB/s
Dirty rate: 35040 pages/s
Page size: 4096 bytes
Iteration: 197
Constant pages: 1751031
Normal pages: 31041965
Normal data: 118.416 GiB
Expected downtime: 3314 ms
Setup time: 70 ms

 

https://www.redhat.com/archives/libvirt-users/2014-January/msg00007.html
https://specs.openstack.org/openstack/nova-specs/specs/mitaka/implemented/abort-live-migration.html

 

https://www.server24.eu/private-cloud/complete-live-migration-vms-high-load/