On 1/23/14 1:46 AM, Matthieu Huin wrote:
Hello Christian,
----- Original Message -----
From: "Christian Schwede" <christian.schw...@enovance.com>
To: "OpenStack Development Mailing List (not for usage questions)"
<openstack-dev@lists.openstack.org>, "Matthieu
Huin" <matthieu.h...@enovance.com>
Sent: Wednesday, January 22, 2014 10:47:24 PM
Subject: Re: [openstack-dev] [Swift] domain-level quotas
Hi Matthieu,
Am 22.01.14 20:02, schrieb Matthieu Huin:
The idea is to have a middleware checking a domain's current usage
against a limit set in the configuration before allowing an upload.
The domain id can be extracted from the token, then used to query
keystone for a list of projects belonging to the domain. Swift would
then compute the domain usage in a similar fashion as the way it is
currently done for accounts, and proceed from there.
the problem might be to compute the current usage of all accounts within
a domain. It won't be a problem if you have only a few accounts in a
domain, but with tens, hundreds or even thousands accounts in a domain
there will be a performance impact because you need to iterate over all
accounts (doing a HEAD on every account) and sum up the total usage.
One might object that this is already a concern when applying quotas
to potentially huge accounts with lots of containers, although I agree
that domains add an order of magnitude to this problem.
Swift accounts and containers keep track* of the total object count and
size, so account/container quotas need only perform a single HEAD
request to get the current usage. The number of containers per account
or objects per container doesn't affect the speed with which the quota
check runs.
Since domains don't map directly to a single entity in Swift, getting
the usage for a domain requires making O(N) requests to fetch the
individual usage data. Domain quotas wouldn't just make usage checks "an
order of magnitude" more costly; they'd take it from roughly constant to
potentially unbounded.
* subject to eventual consistency, of course
_______________________________________________
OpenStack-dev mailing list
OpenStack-dev@lists.openstack.org
http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
