[ovs-dev] [PATCH v3 0/5] Fast OVSDB resync after restart or fail-over.

Ben Pfaff blp at ovn.org
Mon Feb 25 19:24:21 UTC 2019


It didn't get caught in any filters this time.

I see all the patches, although maybe I was CCed.

On Mon, Feb 25, 2019 at 11:08:40AM -0800, Han Zhou wrote:
> This seems not showing up in the mailing list. Retry sending using
> different words in title.
> On Mon, Feb 25, 2019 at 9:25 AM Han Zhou <zhouhan at gmail.com> wrote:
> >
> > In scalability test with ovn-scale-test, ovsdb-server SB load is not a
> > problem at least with 1k HVs. However, if we restart the ovsdb-server,
> > depending on the number of HVs and scale of logical objects, e.g. the
> > number of logical ports, ovsdb-server of SB become an obvious bottleneck.
> >
> > In our test with 1k HVs and 20k logical ports (200 lport * 100 lswitches
> > connected by one single logical router). Restarting ovsdb-server of SB
> > resulted in 100% CPU of ovsdb-server for more than 1 hour. All HVs (and
> > northd) are reconnecting and resyncing the big amount of data at the same
> > time.
> >
> > Similar problem would happen in failover scenario. With active-active
> > cluster, the problem can be aleviated slightly, because only 1/3 (assuming
> > it is 3-node cluster) of the HVs will need to resync data from new servers,
> > but it is still a serious problem.
> >
> > For detailed discussions for the problem and solutions, see:
> > https://mail.openvswitch.org/pipermail/ovs-discuss/2018-October/047591.html
> >
> > The patches implements the proposal in that discussion. It introduces
> > a new method monitor_cond_since to enable client to request changes that
> > happened after a specific point so that the data has been cached already
> > in client are not re-transfered. Scalability test shows dramatic improvement.
> > All HVs finishes sync as soon as they reconnect since there is no new data
> > to be transfered.
> >
> > The current patches supports all 3 modes of ovsdb-server, but only clustered
> > mode can benefit from it, since it is the only one that supports transaction
> > id out of the box.
> >
> > ---
> > v1 -> v2: fix the unused variable in patch 6/7 reported by 0-day.
> > v2 -> v3: first 2 in the 7 were merged. Revised 1/5 addressing Ben's
> > comment on the json cache hmap.
> >
> > Han Zhou (5):
> >   ovsdb-monitor: Refactor ovsdb monitor implementation.
> >   ovsdb-server: Transaction history tracking.
> >   ovsdb-monitor: Support monitor_cond_since.
> >   ovsdb-idl.c: Support monitor_cond_since method in C IDL.
> >   ovsdb-idl.c: Fast resync from server when connection reset.
> >
> >  Documentation/ref/ovsdb-server.7.rst |  78 +++++-
> >  lib/ovsdb-idl.c                      | 229 ++++++++++++----
> >  ovsdb/jsonrpc-server.c               | 101 +++++--
> >  ovsdb/monitor.c                      | 516 ++++++++++++++++++++++-------------
> >  ovsdb/monitor.h                      |  16 +-
> >  ovsdb/ovsdb-client.1.in              |  28 +-
> >  ovsdb/ovsdb-client.c                 | 104 ++++++-
> >  ovsdb/ovsdb-server.c                 |  11 +
> >  ovsdb/ovsdb.c                        |   3 +
> >  ovsdb/ovsdb.h                        |  10 +
> >  ovsdb/transaction.c                  | 117 +++++++-
> >  ovsdb/transaction.h                  |   4 +
> >  tests/ovsdb-monitor.at               | 301 +++++++++++++++++++-
> >  13 files changed, 1232 insertions(+), 286 deletions(-)
> >
> > --
> > 2.1.0
> >
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