aodh/doc/source/measurements.rst

Measurements

Three type of meters are defined in ceilometer:

double: meter; cumulative double: meter; gauge double: meter; delta

Type	Definition
Cumulative	Increasing over time (instance hours)
Gauge	Discrete items (floating IPs, image uploads) and fluctuating values (disk I/O)
Delta	Changing over time (bandwidth)

Units

1. Whenever a volume is to be measured, SI approved units and their approved symbols or abbreviations should be used. Information units should be expressed in bits ('b') or bytes ('B').
2. For a given meter, the units should NEVER, EVER be changed.
3. When the measurement does not represent a volume, the unit description should always described WHAT is measured (ie: apples, disk, routers, floating IPs, etc.).
4. When creating a new meter, if another meter exists measuring something similar, the same units and precision should be used.
5. Meters and samples should always document their units in Ceilometer (API and Documentation) and new sampling code should not be merged without the appropriate documentation.

Dimension	Unit	Abbreviations	Note
None Volume Time	N/A byte seconds	B s	Dimension-less variable

Here are the meter types by components that are currently implemented:

Compute (Nova)

All meters are related to the guest machine, not the host.

Name	Type*	Unit	Resource	Origin**	Support***	Note
instance	g	instance	inst ID	both	1, 2, 3, 4	Existence of instance
instance:<type>	g	instance	inst ID	both	1, 2, 3, 4	Existence of instance <type> (openstack types)
memory	g	MB	inst ID	n	1, 2	Volume of RAM allocated
memory.usage	g	MB	inst ID	p	1, 2, 3, 4	Volume of RAM used
cpu	c	ns	inst ID	p	1, 2	CPU time used
cpu_util	g	%	inst ID	p	1, 2, 3, 4	Average CPU utilisation
vcpus	g	vcpu	inst ID	n	1, 2	Number of VCPUs
disk.read.requests	c	request	inst ID	p	1, 2	Number of read requests
disk.read.requests.rate	g	request/s	inst ID	p	1, 2, 3	Average rate of reads
disk.write.requests	c	request	inst ID	p	1, 2	Number of write requests
disk.write.requests.rate	g	request/s	inst ID	p	1, 2, 3	Average rate of writes
disk.read.bytes	c	B	inst ID	p	1, 2	Volume of reads
disk.read.bytes.rate	g	B/s	inst ID	p	1, 2, 3, 4	Average rate of reads
disk.write.bytes	c	B	inst ID	p	1, 2	Volume of writes
disk.write.bytes.rate	g	B/s	inst ID	p	1, 2, 3, 4	Average volume of writes
disk.latency	g	ms	inst ID	p	2	Average disk latency
disk.device.read.requests	c	request	disk ID	p	1, 2	Number of read requests
disk.device.read.requests.rate	g	request/s	disk ID	p	1, 2, 3	Average rate of read requests
disk.device.write.requests	c	request	disk ID	p	1, 2	Number of write requests
disk.device.write.requests.rate	g	request/s	disk ID	p	1, 2, 3	Average rate of write requests
disk.device.read.bytes	c	B	disk ID	p	1, 2	Volume of reads
disk.device.read.bytes.rate	g	B/s	disk ID	p	1, 2, 3	Average rate of reads
disk.device.write.bytes	c	B	disk ID	p	1, 2	Volume of writes
disk.device.write.bytes.rate	g	B/s	disk ID	p	1, 2, 3	Average volume of writes
disk.device.latency	g	ms	disk ID	p	2	Average disk latency per device
disk.root.size	g	GB	inst ID	n	1, 2	Size of root disk
disk.ephemeral.size	g	GB	inst ID	n	1, 2	Size of ephemeral disk
network.incoming.bytes	c	B	iface ID	p	1, 2	Number of incoming bytes
network.incoming.bytes.rate	g	B/s	iface ID	p	1, 2, 3, 4	Average rate of incoming bytes
network.outgoing.bytes	c	B	iface ID	p	1, 2	Number of outgoing bytes
network.outgoing.bytes.rate	g	B/s	iface ID	p	1, 2, 3, 4	Average rate of outgoing bytes
network.incoming.packets	c	packet	iface ID	p	1, 2	Number of incoming packets
network.incoming.packets.rate	g	packet/s	iface ID	p	1, 2, 3, 4	Average rate of incoming packets
network.outgoing.packets	c	packet	iface ID	p	1, 2	Number of outgoing packets
network.outgoing.packets.rate	g	packet/s	iface ID	p	1, 2, 3, 4	Average rate of outgoing packets

Legend:
*
[g]: gauge
[c]: cumulative
**
[p]: pollster
[n]: notification
***
[1]: Libvirt support
[2]: HyperV support
[3]: Vsphere support
[4]: XenAPI support

Note

To enable the libvirt memory.usage supporting, you need libvirt version 1.1.1+, qemu version 1.5+, and you need to prepare suitable balloon driver in the image, particularly for Windows guests, most modern Linuxes have it built in. The memory.usage meters can't be fetched without image balloon driver.

Note

On libvirt/hyperV, the following meters are not generated directly from the underlying hypervisor, but are generated by the 'rate_of_change' transformer as defined in the default pipeline configuration.

• cpu_util
• disk.read.requests.rate
• disk.write.requests.rate
• disk.read.bytes.rate
• disk.write.bytes.rate
• disk.device.read.requests.rate
• disk.device.write.requests.rate
• disk.device.read.bytes.rate
• disk.device.write.bytes.rate
• network.incoming.bytes.rate
• network.outgoing.bytes.rate
• network.incoming.packets.rate
• network.outgoing.packets.rate

Contributors are welcome to extend other virtualization backends' meters or complete the existing ones.

The meters below are related to the host machine.

Note

By default, Nova will not collect the following meters related to the host compute node machine. Nova option 'compute_monitors = ComputeDriverCPUMonitor' should be set in nova.conf to enable meters.

Name	Type	Unit	Resource	Origin	Note
compute.node.cpu.frequency	Gauge	MHz	host ID	notification	CPU frequency
compute.node.cpu.kernel.time	Cumulative	ns	host ID	notification	CPU kernel time
compute.node.cpu.idle.time	Cumulative	ns	host ID	notification	CPU idle time
compute.node.cpu.user.time	Cumulative	ns	host ID	notification	CPU user mode time
compute.node.cpu.iowait.time	Cumulative	ns	host ID	notification	CPU I/O wait time
compute.node.cpu.kernel.percent	Gauge	%	host ID	notification	CPU kernel percentage
compute.node.cpu.idle.percent	Gauge	%	host ID	notification	CPU idle percentage
compute.node.cpu.user.percent	Gauge	%	host ID	notification	CPU user mode percentage
compute.node.cpu.iowait.percent	Gauge	%	host ID	notification	CPU I/O wait percentage
compute.node.cpu.percent	Gauge	%	host ID	notification	CPU utilization

Network (Neutron)

Name	Type	Unit	Resource	Origin	Note
network	Gauge	network	netw ID	notification	Existence of network
network.create	Delta	network	netw ID	notification	Creation requests for this network
network.update	Delta	network	netw ID	notification	Update requests for this network
subnet	Gauge	subnet	subnt ID	notification	Existence of subnet
subnet.create	Delta	subnet	subnt ID	notification	Creation requests for this subnet
subnet.update	Delta	subnet	subnt ID	notification	Update requests for this subnet
port	Gauge	port	port ID	notification	Existence of port
port.create	Delta	port	port ID	notification	Creation requests for this port
port.update	Delta	port	port ID	notification	Update requests for this port
router	Gauge	router	rtr ID	notification	Existence of router
router.create	Delta	router	rtr ID	notification	Creation requests for this router
router.update	Delta	router	rtr ID	notification	Update requests for this router
ip.floating	Gauge	ip	ip ID	both	Existence of floating ip
ip.floating.create	Delta	ip	ip ID	notification	Creation requests for this floating ip
ip.floating.update	Delta	ip	ip ID	notification	Update requests for this floating ip
bandwidth	Delta	B	label ID	notification	Bytes through this l3 metering label

Image (Glance)

Name	Type	Unit	Resource	Origin	Note
image	Gauge	image	image ID	both	Image polling -> it (still) exists
image.size	Gauge	B	image ID	both	Uploaded image size
image.update	Delta	image	image ID	notification	Number of update on the image
image.upload	Delta	image	image ID	notification	Number of upload of the image
image.delete	Delta	image	image ID	notification	Number of delete on the image
image.download	Delta	B	image ID	notification	Image is downloaded
image.serve	Delta	B	image ID	notification	Image is served out

Volume (Cinder)

Name	Type	Unit	Resource	Origin	Note
volume	Gauge	volume	vol ID	notification	Existence of volume
volume.size	Gauge	GB	vol ID	notification	Size of volume
volume.create.(start|end)	Delta	volume	vol ID	notification	Creation of volume
volume.delete.(start|end)	Delta	volume	vol ID	notification	Deletion of volume
volume.update.(start|end)	Delta	volume	vol ID	notification	Update volume(name or description)
volume.resize.(start|end)	Delta	volume	vol ID	notification	Update volume size
volume.attach.(start|end)	Delta	volume	vol ID	notification	Attaching volume to instance
volume.detach.(start|end)	Delta	volume	vol ID	notification	Detaching volume from instance
snapshot	Gauge	snapshot	snap ID	notification	Existence of snapshot
snapshot.size	Gauge	GB	snap ID	notification	Size of snapshot's volume
snapshot.create.(start|end)	Delta	snapshot	snap ID	notification	Creation of snapshot
snapshot.delete.(start|end)	Delta	snapshot	snap ID	notification	Deletion of snapshot
snapshot.update.(start|end)	Delta	snapshot	snap ID	notification	Update snapshot(name or description)

Make sure Cinder is properly configured first: see installing_manually.

Identity (Keystone)

Name	Type	Unit	Resource	Origin	Note
identity.authenticate.success	Delta	user	user ID	notification	User successfully authenticates
identity.authenticate.pending	Delta	user	user ID	notification	User pending authentication
identity.authenticate.failure	Delta	user	user ID	notification	User failed authentication
identity.role_assignment.created	Delta	role_assignment	role ID	notification	A role is added to an actor on a target
identity.role_assignment.deleted	Delta	role_assignment	role ID	notification	A role is removed from an actor on a target
identity.user.created	Delta	user	user ID	notification	A user is created
identity.user.deleted	Delta	user	user ID	notification	A user is deleted
identity.user.updated	Delta	user	user ID	notification	A user is updated
identity.group.created	Delta	group	group ID	notification	A group is created
identity.group.deleted	Delta	group	group ID	notification	A group is deleted
identity.group.updated	Delta	group	group ID	notification	A group is updated
identity.role.created	Delta	role	role ID	notification	A role is created
identity.role.deleted	Delta	role	role ID	notification	A role is deleted
identity.role.updated	Delta	role	role ID	notification	A role is updated
identity.project.created	Delta	project	project ID	notification	A project is created
identity.project.deleted	Delta	project	project ID	notification	A project is deleted
identity.project.updated	Delta	project	project ID	notification	A project is updated
identity.trust.created	Delta	trust	trust ID	notification	A trust is created
identity.trust.deleted	Delta	trust	trust ID	notification	A trust is deleted

Object Storage (Swift)

Name	Type	Unit	Resource	Origin	Note
storage.objects	Gauge	object	store ID	pollster	Number of objects
storage.objects.size	Gauge	B	store ID	pollster	Total size of stored objects
storage.objects.containers	Gauge	container	store ID	pollster	Number of containers
storage.objects.incoming.bytes	Delta	B	store ID	notification	Number of incoming bytes
storage.objects.outgoing.bytes	Delta	B	store ID	notification	Number of outgoing bytes
storage.api.request	Delta	request	store ID	notification	Number of API requests against swift
storage.containers.objects	Gauge	object	str ID/cont	pollster	Number of objects in container
storage.containers.objects.size	Gauge	B	str ID/cont	pollster	Total size of stored objects in container

In order to use storage.objects.incoming.bytes and storage.outgoing.bytes, one must configure Swift as described in installing_manually. Note that they may not be updated right after an upload/download, since Swift takes some time to update the container properties.

Orchestration (Heat)

Name	Type	Unit	Resource	Origin	Note
stack.create	Delta	stack	stack ID	notification	Creation requests for a stack successful
stack.update	Delta	stack	stack ID	notification	Updating requests for a stack successful
stack.delete	Delta	stack	stack ID	notification	Deletion requests for a stack successful
stack.resume	Delta	stack	stack ID	notification	Resuming requests for a stack successful
stack.suspend	Delta	stack	stack ID	notification	Suspending requests for a stack successful

To enable Heat notifications configure Heat as described in installing_manually.

Data Processing (Sahara)

Name	Type	Unit	Resource	Origin	Note
cluster.create	Delta	cluster	cluster ID	notification	Creation requests for a cluster successful
cluster.update	Delta	cluster	cluster ID	notification	Updating status requests for a cluster successful
cluster.delete	Delta	cluster	cluster ID	notification	Deletion requests for a cluster successful

To enable Sahara notifications configure Sahara as described in installing_manually.

Key Value Store (MagnetoDB)

Name	Type	Unit	Resource	Origin	Note
magnetodb.table.create	Gauge	table	table ID	notification	Creation requests for a table successful
magnetodb.table.delete	Gauge	table	table ID	notification	Deletion requests for a table successful
magnetodb.table.index.count	Gauge	index	table ID	notification	Number of indices created in a table

To enable MagnetoDB notifications configure MagnetoDB as described in installing_manually.

Energy (Kwapi)

Name	Type	Unit	Resource	Origin	Note
energy	Cumulative	kWh	probe ID	pollster	Amount of energy
power	Gauge	W	probe ID	pollster	Power consumption

Network (From SDN Controller)

These meters based on OpenFlow Switch metrics. In order to enable these meters, each driver needs to be configured.

Meter	Type	Unit	Resource	Origin	Note
switch	Gauge	switch	switch ID	pollster	Existence of switch
switch.port	Gauge	port	switch ID	pollster	Existence of port
switch.port.receive.packets	Cumulative	packet	switch ID	pollster	Received Packets
switch.port.transmit.packets	Cumulative	packet	switch ID	pollster	Transmitted Packets
switch.port.receive.bytes	Cumulative	B	switch ID	pollster	Received Bytes
switch.port.transmit.bytes	Cumulative	B	switch ID	pollster	Transmitted Bytes
switch.port.receive.drops	Cumulative	packet	switch ID	pollster	Receive Drops
switch.port.transmit.drops	Cumulative	packet	switch ID	pollster	Transmit Drops
switch.port.receive.errors	Cumulative	packet	switch ID	pollster	Receive Errors
switch.port.transmit.errors	Cumulative	packet	switch ID	pollster	Transmit Errors
switch.port.receive.frame_error	Cumulative	packet	switch ID	pollster	Receive Frame Alignment Errors
switch.port.receive.overrun_error	Cumulative	packet	switch ID	pollster	Receive Overrun Errors
switch.port.receive.crc_error	Cumulative	packet	switch ID	pollster	Receive CRC Errors
switch.port.collision.count	Cumulative	count	switch ID	pollster	Collisions
switch.table	Gauge	table	switch ID	pollster	Duration of Table
switch.table.active.entries	Gauge	entry	switch ID	pollster	Active Entries
switch.table.lookup.packets	Gauge	packet	switch ID	pollster	Packet Lookups
switch.table.matched.packets	Gauge	packet	switch ID	pollster	Packet Matches
switch.flow	Gauge	flow	switch ID	pollster	Duration of Flow
switch.flow.duration.seconds	Gauge	s	switch ID	pollster	Duration(seconds)
switch.flow.duration.nanoseconds	Gauge	ns	switch ID	pollster	Duration(nanoseconds)
switch.flow.packets	Cumulative	packet	switch ID	pollster	Received Packets
switch.flow.bytes	Cumulative	B	switch ID	pollster	Received Bytes

LoadBalancer as a Service (LBaaS)

Meter	Type	Unit	Resource	Origin	Note
network.services.lb.pool	Gauge	pool	pool ID	both	Existence of a LB Pool
network.services.lb.pool.create	Delta	pool	pool ID	notification	Creation of a LB Pool
network.services.lb.pool.update	Delta	pool	pool ID	notification	Update of a LB Pool
network.services.lb.vip	Gauge	vip	vip ID	both	Existence of a LB Vip
network.services.lb.vip.create	Delta	vip	vip ID	notification	Creation of a LB Vip
network.services.lb.vip.update	Delta	vip	vip ID	notification	Update of a LB Vip
network.services.lb.member	Gauge	member	member ID	both	Existence of a LB Member
network.services.lb.member.create	Delta	member	member ID	notification	Creation of a LB Member
network.services.lb.member.update	Delta	member	member ID	notification	Update of a LB Member
network.services.lb.health_monitor	Gauge	monitor	monitor ID	both	Existence of a LB Health Probe
network.services.lb.health_monitor.create	Delta	monitor	monitor ID	notification	Creation of a LB Health Probe
network.services.lb.health_monitor.update	Delta	monitor	monitor ID	notification	Update of a LB Health Probe
network.services.lb.total.connections	Cumulative	connection	pool ID	pollster	Total connections on a LB
network.services.lb.active.connections	Gauge	connection	pool ID	pollster	Active connections on a LB
network.services.lb.incoming.bytes	Cumulative	B	pool ID	pollster	Number of incoming Bytes
network.services.lb.outgoing.bytes	Cumulative	B	pool ID	pollster	Number of outgoing Bytes

VPN as a Service (VPNaaS)

Meter	Type	Unit	Resource	Origin	Note
network.services.vpn	Gauge	vpn	vpn ID	both	Existence of a VPN service
network.services.vpn.create	Delta	vpn	vpn ID	notification	Creation of a VPN service
network.services.vpn.update	Delta	vpn	vpn ID	notification	Update of a VPN service
network.services.vpn.connections	Gauge	connection	connection ID	both	Existence of a IPSec Connection
network.services.vpn.connections.create	Delta	connection	connection ID	notification	Creation of a IPSec Connection
network.services.vpn.connections.update	Delta	connection	connection ID	notification	Update of a IPSec Connection
network.services.vpn.ipsecpolicy	Gauge	ipsecpolicy	ipsecpolicy ID	notification	Existence of a IPSec Policy
network.services.vpn.ipsecpolicy.create	Delta	ipsecpolicy	ipsecpolicy ID	notification	Creation of a IPSec Policy
network.services.vpn.ipsecpolicy.update	Delta	ipsecpolicy	ipsecpolicy ID	notification	Update of a IPSec Policy
network.services.vpn.ikepolicy	Gauge	ikepolicy	ikepolicy ID	notification	Existence of a Ike Policy
network.services.vpn.ikepolicy.create	Delta	ikepolicy	ikepolicy ID	notification	Creation of a Ike Policy
network.services.vpn.ikepolicy.update	Delta	ikepolicy	ikepolicy ID	notification	Update of a Ike Policy

Firewall as a Service (FWaaS)

Meter	Type	Unit	Resource	Origin	Note
network.services.firewall	Gauge	firewall	firewall ID	both	Existence of a Firewall service
network.services.firewall.create	Delta	firewall	firewall ID	notification	Creation of a Firewall service
network.services.firewall.update	Delta	firewall	firewall ID	notification	Update of a Firewall service
network.services.firewall.policy	Gauge	policy	policy ID	both	Existence of a Firewall Policy
network.services.firewall.policy.create	Delta	policy	policy ID	notification	Creation of a Firewall Policy
network.services.firewall.policy.update	Delta	policy	policy ID	notification	Update of a Firewall Policy
network.services.firewall.rule	Gauge	rule	rule ID	notification	Existence of a Firewall Rule
network.services.firewall.rule.create	Delta	rule	rule ID	notification	Creation of a Firewall Rule
network.services.firewall.rule.update	Delta	rule	rule ID	notification	Update of a Firewall Rule

Ironic Hardware IPMI Sensor Data

IPMI sensor data is not available by default in Ironic. To enable these meters see the Ironic Installation Guide.

Meter	Type	Unit	Resource	Origin	Note
hardware.ipmi.fan	Gauge	RPM	fan sensor	notification	Fan RPM
hardware.ipmi.temperature	Gauge	C	temp sensor	notification	Sensor Temperature Reading
hardware.ipmi.current	Gauge	W	current sensor	notification	Sensor Current Reading
hardware.ipmi.voltage	Gauge	V	voltage sensor	notification	Sensor Voltage Reading

There is another way to retrieve IPMI data, by deploying the Ceilometer IPMI agent on each IPMI-capable node in order to poll local sensor data. To avoid duplication of metering data and unnecessary load on the IPMI interface, the IPMI agent should not be deployed if the node is managed by Ironic and the 'conductor.send_sensor_data' option is set to true in the Ironic configuration.

IPMI agent also retrieve following Node Manager meter besides original IPMI sensor data:

Meter	Type	Unit	Resource	Origin	Note
hardware.ipmi.node.power	Gauge	W	host ID	pollster	System Current Power
hardware.ipmi.node.temperature	Gauge	C	host ID	pollster	System Current Temperature

Generic Host

These meters are generic host metrics getting from snmp. To enable these, snmpd agent should be running on the host from which the metrics are gathered.

Meter	Type*	Unit	Resource	Origin	Note
hardware.cpu.load.1min	g	process	host ID	pollster	CPU load in the past 1 minute
hardware.cpu.load.5min	g	process	host ID	pollster	CPU load in the past 5 minutes
hardware.cpu.load.15min	g	process	host ID	pollster	CPU load in the past 15 minutes
hardware.disk.size.total	g	B	disk ID	pollster	Total disk size
hardware.disk.size.used	g	B	disk ID	pollster	Used disk size
hardware.memory.total	g	B	host ID	pollster	Total physical memory size
hardware.memory.used	g	B	host ID	pollster	Used physical memory size
hardware.memory.swap.total	g	B	host ID	pollster	Total swap space size
hardware.memory.swap.avail	g	B	host ID	pollster	Available swap space size
hardware.network.incoming.bytes	c	B	iface ID	pollster	Bytes received by network interface
hardware.network.outgoing.bytes	c	B	iface ID	pollster	Bytes sent by network interface
hardware.network.outgoing.errors	c	packet	iface ID	pollster	Sending error of network interface
hardware.network.ip.incoming.datagrams	c	datagrams	host ID	pollster	Number of received datagrams
hardware.network.ip.outgoing.datagrams	c	datagrams	host ID	pollster	Number of sent datagrams
hardware.system_stats.io.incoming.blocks	c	blocks	host ID	pollster	Aggregated number of blocks received to block device
hardware.system_stats.io.outgoing.blocks	c	blocks	host ID	pollster	Aggregated number of blocks sent to block device
hardware.system_stats.cpu.idle	g	%	host ID	pollster	CPU idle percentage

Legend:
*
[g]: gauge
[c]: cumulative

Dynamically retrieving the Meters via ceilometer client

To retrieve the available meters that can be queried given the actual resource instances available, use the meter-list command:

$ ceilometer meter-list
+------------+-------+--------------------------------------+---------+----------------------------------+
| Name       | Type  | Resource ID                          | User ID | Project ID                       |
+------------+-------+--------------------------------------+---------+----------------------------------+
| image      | gauge | 09e84d97-8712-4dd2-bcce-45970b2430f7 |         | 57cf6d93688e4d39bf2fe3d3c03eb326 |

Naming convention

If you plan on adding meters, please follow the convention below:

1. Always use '.' as separator and go from least to most discriminant word. For example, do not use ephemeral_disk_size but disk.ephemeral.size
2. When a part of the name is a variable, it should always be at the end and start with a ':'. For example do not use <type>.image but image:<type>, where type is your variable name.
3. If you have any hesitation, come and ask in #openstack-ceilometer

User-defined sample metadata for Nova

Users are allowed to add additional metadata to samples of nova meter. These additional metadata are stored in 'resource_metadata.user_metadata.*' of the sample.

To do so, users can add nova user metadata prefixed with 'metering.':

$ nova boot --meta metering.custom_metadata=a_value my_vm

Or users can define metadata keys they cared without any prefix in ceilometer.conf. For example,if users need to add "fqdn" of metadata to samples, they can add or modify as below into ceilometer.conf in [DEFAULT] group:

reserved_metadata_keys=fqdn

Note: The name of the metadata shouldn't exceed 256 characters otherwise it will be cut off. Also, if it has '.', this will be replaced by a '_' in ceilometer.

User-defined sample metadata for Swift

It's possible to add additional metadata to sample of Swift meter as well. You might specify headers whose values will be stored in resource_metadata as 'resource_metadata.http_header$name', where $name is a name of the header with '-' replaced by '_'.

This is done using 'metadata_headers' option in middleware configuration, refer to installing_manually for details.

For example, this could be used to distinguish external and internal users. You'd have to implement a custom Swift middleware that sets a proper header and just add it to metadata_headers.

OSprofiler data

All messages with event type "profiler.*" will be collected as profiling data. Using notification plugin profiler/notifications.py.

Note

Be sparing with heavy usage of OSprofiler, especially in case of complex operations like booting and deleting instance that may create over 100kb of sample data per each request.