Richard Elling via illumos-discuss wrote:
New thread, the previous was about kernel-level clustering, not layered
software.
On Dec 23, 2014, at 2:15 PM, Miles Fidelman via illumos-discuss
<[email protected]> wrote:
It really is a pain.
HA is hard. DR is hard. HA + DR is hard.
In the Linux world, Xen or KVM + DRBD + Pacemaker + CRM gives you a relatively
painless HA cluster.
This is block-level replication.
In the BSD world, there's HAST + CARP get you pretty far along the same path.
Also block-level replication.
But there's nothing equivalent in the illumos world (Xen is pretty thin too).
The illumos equivalent for block-level replication is AVS. This works ok for
small systems.
Nexenta even productized it under the moniker "Simple HA" Unfortunately it
doesn't work
well for systems in the TB+ range due to the architectural issues of moving
large amounts
of data and the speed of light. Few illumos vendors work on small systems and
even
Nexenta killed "Simple HA"
Today, most vendors do something other than block-level replication for large scale
HA & DR.
Most people use dataset replication or application-level redundancy in the
illumos world.
There are commercially-supported, general-purpose clustering solutions, such as
RSF-1.
If you want to roll your own, I'd suggest pacemaker/heartbeat and znapzend as
good open-source
starting points.
Well... AVS seems to be just about dead, and undocumented, and znapzend
is not continuous replication - doesn't seem like an HA solution.
I should point out that in the commercial world there are also VMware
and SANs - that also do block level replication.
Kind of a large gap when it comes to using illumos in any kind of production
environment.
I don't see a large gap in capabilities. Many thousands of illumos-based
systems are in
production with HA and DR.
-- richard
Not with FOSS underpinnings. Unless I'm missing something really big.
I'd sure like to be wrong on this.
Miles Fidelman
--
In theory, there is no difference between theory and practice.
In practice, there is. .... Yogi Berra
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