Why are such large disk sizes required? (instance flavors for CF on OpenStack)

[kinjelom]

In this doc docs-deploying-cf/openstack/required-flavors.html.md.erb is written:

[...] flavors must have the following listed specifications, at minimum:

Flavor Name	VCPUs	RAM (GB)	Root Disk (GB)	Ephemeral Disk (GB)
m1.small	1	2	10	20
m1.medium	2	4	10	40
m1.large	4	8	10	80
m1.xlarge	8	16	10	160

I found that when I reduce flavors disk sizes to these values:

Flavor Name	VCPUs	RAM (GB)	Root Disk (GB)	Ephemeral Disk (GB)
m1.small	1	2	4	4
m1.medium	2	4	4	8
m1.large	4	8	4	16
m1.xlarge	8	16	4	32

then instances disks usage in my deployment look like this (bosh instance --ps):

Instance	RAM Usage	Swap Usage	System Disk Usage	Ephemeral Disk Usage	Persistent Disk Usage
api_z1	10% (838MB)	0%	29% (23i%)	6% (5i%)	-
blobstore_z1	3% (134MB)	0%	29% (23i%)	3% (1i%)	0% (0i%)
clock_z1	7% (290MB)	0%	29% (23i%)	12% (10i%)	-
consul_z1	5% (95MB)	0%	29% (23i%)	5% (3i%)	0% (0i%)
doppler_z1	4% (142MB)	0%	29% (23i%)	4% (1i%)	-
etcd_z1	2% (168MB)	0%	29% (23i%)	2% (1i%)	0% (0i%)
ha_proxy_z1	3% (117MB)	0%	29% (23i%)	3% (1i%)	-
loggregator[...]_z1	5% (100MB)	0%	29% (23i%)	6% (3i%)	-
nats_z1	3% (109MB)	0%	29% (23i%)	3% (1i%)	-
postgres_z1	3% (140MB)	0%	29% (23i%)	4% (3i%)	2% (1i%)
router_z1	3% (114MB)	0%	29% (23i%)	3% (2i%)	-
stats_z1	6% (125MB)	0%	29% (23i%)	13% (6i%)	-
uaa_z1	18% (711MB)	0%	29% (23i%)	13% (2i%)	-

Why are such large disk sizes required by default?
Doesn't it slow down IaaS operations?

[cf-gitbot]

We have created an issue in Pivotal Tracker to manage this:

https://www.pivotaltracker.com/story/show/151215943

The labels on this github issue will be updated when the story is started.

[cf-pub-tools]

Hi @wildloop

This documentation repository is maintained by technical writers, not developers or support engineering.

If you have questions about the open source Cloud Foundry project, we recommend that you contact the cf-dev@lists.cloudfoundry.org mailing list.

For questions about Pivotal Cloud Foundry, please contact Pivotal support: https://support.pivotal.io

Thank you.

[kinjelom]

Thanks,
There are the flavors with the new names and configuration (cf-deployment):
https://github.com/cloudfoundry/cf-deployment/tree/master/iaas-support/openstack