8:57 a.m.
Hi David,
it's a little bit different.
Ovirt supports 'replica 3' (3 directories hsot the same content) or
'replica 3 arbiter 1' (2 directories host same data, third directory contains
metadata to prevent split brain situations) volumes.
If you have 'replica 3' it is smart to keep the data on separate hosts, although
you can keep it on the same host (but then you should use no replica and oVirt's
Single node setup).
When you extend , yoou need to add bricks (fancy name for a directory) in the x3 count.
If you wish that you want to use 5 nodes, you can go with 'replica 3 arbiter 1'
volume, where ServerA & ServerB host data and ServerC host only metadata (arbiter).
Then you can extend and for example ServerC can host again metadata while ServerD &
ServerE host data for the second replica set.
You can even use only 3 servers for Gluster , while much more systems as ovirt nodes (CPU
& RAM) to host VMs.
In case of a 4 node setup - 3 hosts have the gluster data and the 4th - is not part of ths
gluster, just hosting VMs.
Best Regards,
Strahil Nikolov
На 19 юли 2020 г. 15:25:10 GMT+03:00, David White via Users <users(a)ovirt.org>
написа:
>Thanks again for explaining all of this to me.
>Much appreciated.
>
>Regarding the hyperconverged environment,
>reviewing https://www.ovirt.org/documentation/gluster-hyperconverged/chap-Deploying_Hyperconverged.html,
>it appears to state that you need, exactly, 3 physical servers.
>
>Is it possible to run a hyperconverged environment with more than 3
>physical servers?
>Because of the way that the gluster triple-redundancy works, I knew
>that I would need to size all 3 physical servers' SSD drives to store
>100% of the data, but there's a possibility that 1 particular (future)
>customer is going to need about 10TB of disk space.
>
>For that reason, I'm thinking about what it would look like to have 4
>or even 5 physical servers in order to increase the total amount of
>disk space made available to oVirt as a whole. And then from there, I
>would of course setup a number of virtual disks that I would attach
>back to that customer's VM.
>
>So to recap, if I were to have a 5-node Gluster Hyperconverged
>environment, I'm hoping that the data would still only be required to
>replicate across 3 nodes. Does this make sense? Is this how data
>replication works? Almost like a RAID -- add more drives, and the RAID
>gets expanded?
>
>Sent with ProtonMail Secure Email.
>
>‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
>On Tuesday, June 23, 2020 4:41 PM, Jayme <jaymef(a)gmail.com> wrote:
>
>> Yes this is the point of hyperconverged. You only need three hosts to
>setup a proper hci cluster. I would recommend ssds for gluster storage.
>You could get away with non raid to save money since you can do replica
>three with gluster meaning your data is fully replicated across all
>three hosts.
>>
>
>> On Tue, Jun 23, 2020 at 5:17 PM David White via Users
><users(a)ovirt.org> wrote:
>>
>
>> > Thanks.
>> > I've only been considering SSD drives for storage, as that is what
>I currently have in the cloud.
>> >
>
>> > I think I've seen some things in the documents about oVirt and
>gluster hyperconverged.
>> > Is it possible to run oVirt and Gluster together on the same
>hardware? So 3 physical hosts would run CentOS or something, and I
>would install oVirt Node + Gluster onto the same base host OS? If so,
>then I could probably make that fit into my budget.
>> >
>
>> > Sent with ProtonMail Secure Email.
>> >
>
>> > ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
>> > On Monday, June 22, 2020 1:02 PM, Strahil Nikolov via Users
><users(a)ovirt.org> wrote:
>> >
>
>> > > Hey David,
>> > >
>> >
>
>> > > keep in mind that you need some big NICs.
>> > > I started my oVirt lab with 1 Gbit NIC and later added 4
>dual-port 1 Gbit NICs and I had to create multiple gluster volumes and
>multiple storage domains.
>> > > Yet, windows VMs cannot use software raid for boot devices, thus
>it's a pain in the @$$.
>> > > I think that optimal is to have several 10Gbit NICs (at least 1
>for gluster and 1 for oVirt live migration).
>> > > Also, NVMEs can be used as lvm cache for spinning disks.
>> > >
>> >
>
>> > > Best Regards,
>> > > Strahil Nikolov
>> > >
>> >
>
>> > > На 22 юни 2020 г. 18:50:01 GMT+03:00, David White
>dmwhite823(a)protonmail.com написа:
>> > >
>> >
>
>> > > > > For migration between hosts you need a shared storage. SAN,
>Gluster,
>> > > > > CEPH, NFS, iSCSI are among the ones already supported (CEPH
>is a little
>> > > > > bit experimental).
>> > > >
>> >
>
>> > > > Sounds like I'll be using NFS or Gluster after all.
>> > > > Thank you.
>> > > >
>> >
>
>> > > > > The engine is just a management layer. KVM/qemu has that
>option a
>> > > > > long time ago, yet it's some manual work to do it.
>> > > > > Yeah, this environment that I'm building is expected to
grow
>over time
>> > > > > (although that growth could go slowly), so I'm trying to
>architect
>> > > > > things properly now to make future growth easier to deal
>with. I'm also
>> > > > > trying to balance availability concerns with budget
>constraints
>> > > > > starting out.
>> > > >
>> >
>
>> > > > Given that NFS would also be a single point of failure, I'll
>probably
>> > > > go with Gluster, as long as I can fit the storage requirements
>into the
>> > > > overall budget.
>> > > > Sent with ProtonMail Secure Email.
>> > > > ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
>> > > > On Monday, June 22, 2020 6:31 AM, Strahil Nikolov via Users
>> > > > users(a)ovirt.org wrote:
>> > > >
>> >
>
>> > > > > На 22 юни 2020 г. 11:06:16 GMT+03:00, David White via
>> > > > > Usersusers(a)ovirt.org написа:
>> > > >
>> >
>
>> > > > > > Thank you and Strahil for your responses.
>> > > > > > They were both very helpful.
>> > > >
>> >
>
>> > > > > > > I think a hosted engine installation VM wants 16GB
RAM
>configured
>> > > > > > > though I've built older versions with 8GB RAM.
>> > > > > > > For modern VMs CentOS8 x86_64 recommends at least
2GB for
>a host.
>> > > > > > > CentOS7 was OK with 1, CentOS6 maybe 512K.
>> > > > > > > The tendency is always increasing with updated OS
>versions.
>> > > >
>> >
>
>> > > > > > Ok, so to clarify my question a little bit, I'm
trying to
>figure
>> > > > > > out
>> > > > >
>> >
>
>> > > > > > how much RAM I would need to reserve for the host OS
(or
>oVirt
>> > > > > > Node).
>> > > > >
>> >
>
>> > > > > > I do recall that CentOS / RHEL 8 wants a minimum of 2GB,
so
>perhaps
>> > > > > > that would suffice?
>> > > > > > And then as you noted, I would need to plan to give the
>engine
>> > > > > > 16GB.
>> > > >
>> >
>
>> > > > > I run my engine on 4Gb or RAM, but i have no more than 20
>VMs, the
>> > > > > larger the setup - the more ram for the engine is needed.
>> > > >
>> >
>
>> > > > > > > My minimum ovirt systems were mostly 48GB 16core,
but
>most are
>> > > > > > > now
>> > > > >
>> >
>
>> > > > > > > 128GB 24core or more.
>> > > >
>> >
>
>> > > > > > But this is the total amount of physical RAM in your
>systems,
>> > > > > > correct?
>> > > > >
>> >
>
>> > > > > > Not the amount that you've reserved for your host
OS?I've
>spec'd
>> > > > > > out
>> > > > >
>> >
>
>> > > > > > some hardware, and am probably looking at purchasing
two
>PowerEdge
>> > > > > > R820's to start, each with 64GB RAM and 32 cores.
>> > > >
>> >
>
>> > > > > > > While ovirt can do what you would like it to do
>concerning a
>> > > > > > > single
>> > > > >
>> >
>
>> > > > > > > user interface, but with what you listed,
>> > > > > > > you're probably better off with just plain
KVM/qemu and
>using
>> > > > > > > virt-manager for the interface.
>> > > >
>> >
>
>> > > > > > Can you migrate VMs from 1 host to another with
>virt-manager, and
>> > > > > > can
>> > > > >
>> >
>
>> > > > > > you take snapshots?
>> > > > > > If those two features aren't supported by
virt-manager,
>then that
>> > > > > > would
>> > > > >
>> >
>
>> > > > > > almost certainly be a deal breaker.
>> > > >
>> >
>
>> > > > > The engine is just a management layer. KVM/qemu has that
>option a
>> > > > > long time ago, yet it's some manual work to do it.
>> > > >
>> >
>
>> > > > > > Come to think of it, if I decided to use local storage
on
>each of
>> > > > > > the
>> > > > >
>> >
>
>> > > > > > physical hosts, would I be able to migrate VMs?
>> > > > > > Or do I have to use a Gluster or NFS store for that?
>> > > >
>> >
>
>> > > > > For migration between hosts you need a shared storage. SAN,
>Gluster,
>> > > > > CEPH, NFS, iSCSI are among the ones already supported (CEPH
>is a little
>> > > > > bit experimental).
>> > > >
>> >
>
>> > > > > > ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
>> > > > > > On Sunday, June 21, 2020 5:58 PM, Edward Berger
>edwberger(a)gmail.com
>> > > > > > wrote:
>> > > >
>> >
>
>> > > > > > > While ovirt can do what you would like it to do
>concerning a
>> > > > > > > single
>> > > > >
>> >
>
>> > > > > > > user interface, but with what you listed,
>> > > > > > > you're probably better off with just plain
KVM/qemu and
>using
>> > > > > > > virt-manager for the interface.
>> > > >
>> >
>
>> > > > > > > Those memory/cpu requirements you listed are really
tiny
>and I
>> > > > > > > wouldn't recommend even trying ovirt on such
challenged
>systems.
>> > > > > > > I would specify at least 3 hosts for a gluster
>hyperconverged
>> > > > > > > system,
>> > > > >
>> >
>
>> > > > > > > and a spare available that can take over if one of
the
>hosts
>> > > > > > > dies.
>> > > > >
>> >
>
>> > > > > >
>> >
>
>> > > >
>> >
>
>> > > > > > > I think a hosted engine installation VM wants 16GB
RAM
>configured
>> > > > > > > though I've built older versions with 8GB RAM.
>> > > > > > > For modern VMs CentOS8 x86_64 recommends at least
2GB for
>a host.
>> > > > > > > CentOS7 was OK with 1, CentOS6 maybe 512K.
>> > > > > > > The tendency is always increasing with updated OS
>versions.
>> > > >
>> >
>
>> > > > > > > My minimum ovirt systems were mostly 48GB 16core,
but
>most are
>> > > > > > > now
>> > > > >
>> >
>
>> > > > > > > 128GB 24core or more.
>> > > >
>> >
>
>> > > > > > > ovirt node ng is a prepackaged installer for an
oVirt
>> > > > > > > hypervisor/gluster host, with its cockpit interface
you
>can
>> > > > > > > create and
>> > > > >
>> >
>
>> > > > > > > install the hosted-engine VM for the user and admin
web
>> > > > > > > interface. Its
>> > > > >
>> >
>
>> > > > > > > very good on enterprise server hardware with lots
of
>RAM,CPU, and
>> > > > > > > DISKS.
>> > > >
>> >
>
>> > > > > > > On Sun, Jun 21, 2020 at 4:34 PM David White via
Users
>> > > > > > > users(a)ovirt.org wrote:
>> > > >
>> >
>
>> > > > > > > > I'm reading through all of the
documentation at
>> > > > > > > > https://ovirt.org/documentation/, and am a
bit
>overwhelmed with
>> > > > > > > > all of
>> > > > >
>> >
>
>> > > > > > > > the different options for installing oVirt.
>> > > >
>> >
>
>> > > > > > > >
>> >
>
>> > > >
>> >
>
>> > > > > >
>> >
>
>> > > >
>> >
>
>> > > > > > > > My particular use case is that I'm looking
for a way to
>manage
>> > > > > > > > VMs
>> > > > >
>> >
>
>> > > > > > > > on multiple physical servers from 1 interface,
and be
>able to
>> > > > > > > > deploy
>> > > > >
>> >
>
>> > > > > > > > new VMs (or delete VMs) as necessary. Ideally,
it would
>be
>> > > > > > > > great if I
>> > > > >
>> >
>
>> > > > > > > > could move a VM from 1 host to a different
host as
>well,
>> > > > > > > > particularly
>> > > > >
>> >
>
>> > > > > > > > in the event that 1 host becomes degraded (bad
HDD, bad
>> > > > > > > > processor,
>> > > > >
>> >
>
>> > > > > > > > etc...)
>> > > >
>> >
>
>> > > > > > > >
>> >
>
>> > > >
>> >
>
>> > > > > >
>> >
>
>> > > >
>> >
>
>> > > > > > > > I'm trying to figure out what the
difference is between
>an
>> > > > > > > > oVirt
>> > > > >
>> >
>
>> > > > > > > > Node and the oVirt Engine, and how the engine
differs
>from the
>> > > > > > > > Manager.
>> > > > >
>> >
>
>> > > > > > >
>> >
>
>> > > >
>> >
>
>> > > > > > > >
>> >
>
>> > > >
>> >
>
>> > > > > >
>> >
>
>> > > >
>> >
>
>> > > > > > > > I get the feeling that `Engine` = `Manager`.
Same
>thing. I
>> > > > > > > > further
>> > > > >
>> >
>
>> > > > > > > > think I understand the Engine to be
essentially
>synonymous with
>> > > > > > > > a
>> > > > >
>> >
>
>> > > > > > > > vCenter VM for ESXi hosts. Is this correct?
>> > > >
>> >
>
>> > > > > > > >
>> >
>
>> > > >
>> >
>
>> > > > > >
>> >
>
>> > > >
>> >
>
>> > > > > > > > If so, then what's the difference between
the
>`self-hosted` vs
>> > > > > > > > the
>> > > > >
>> >
>
>> > > > > > > > `stand-alone` engines?
>> > > >
>> >
>
>> > > > > > > >
>> >
>
>> > > >
>> >
>
>> > > > > >
>> >
>
>> > > >
>> >
>
>> > > > > > > > oVirt Engine requirements look to be a minimum
of 4GB
>RAM and
>> > > > > > > > 2CPUs.
>> > > >
>> >
>
>> > > > > > > > oVirt Nodes, on the other hand, require only
2GB RAM.
>> > > > > > > > Is this a requirement just for the physical
host, or is
>that
>> > > > > > > > how
>> > > > >
>> >
>
>> > > > > > > > much RAM that each oVirt node process
requires? In
>other words,
>> > > > > > > > if I
>> > > > >
>> >
>
>> > > > > > > > have a physical host with 12GB of physical
RAM, will I
>only be
>> > > > > > > > able to
>> > > > >
>> >
>
>> > > > > > > > allocate 10GB of that to guest VMs? How much
of that
>should I
>> > > > > > > > dedicated
>> > > > >
>> >
>
>> > > > > > > > to the oVirt node processes?
>> > > >
>> >
>
>> > > > > > > >
>> >
>
>> > > >
>> >
>
>> > > > > >
>> >
>
>> > > >
>> >
>
>> > > > > > > > Can you install the oVirt Engine as a VM onto
an
>existing oVirt
>> > > > > > > > Node? And then connect that same node to the
Engine,
>once the
>> > > > > > > > Engine is
>> > > > >
>> >
>
>> > > > > > > > installed?
>> > > >
>> >
>
>> > > > > > > >
>> >
>
>> > > >
>> >
>
>> > > > > >
>> >
>
>> > > >
>> >
>
>> > > > > > > > Reading through the documentation, it also
sounds like
>oVirt
>> > > > > > > > Engine
>> > > > >
>> >
>
>> > > > > > > > and oVirt Node require different versions of
RHEL or
>CentOS.
>> > > >
>> >
>
>> > > > > > > > I read that the Engine for oVirt 4.4.0
requires RHEL
>(or
>> > > > > > > > CentOS)
>> > > > >
>> >
>
>> > > > > > > > 8.2, whereas each Node requires 7.x (although
I'll plan
>to just
>> > > > > > > > use the
>> > > > >
>> >
>
>> > > > > > > > oVirt Node ISO).
>> > > >
>> >
>
>> > > > > > > >
>> >
>
>> > > >
>> >
>
>> > > > > >
>> >
>
>> > > >
>> >
>
>> > > > > > > > I'm also wondering about storage.
>> > > > > > > > I don't really like the idea of using
local storage,
>but a
>> > > > > > > > single
>> > > > >
>> >
>
>> > > > > > > > NFS server would also be a single point of
failure, and
>Gluster
>> > > > > > > > would
>> > > > >
>> >
>
>> > > > > > > > be too expensive to deploy, so at this point,
I'm
>leaning
>> > > > > > > > towards using
>> > > > >
>> >
>
>> > > > > > > > local storage.
>> > > >
>> >
>
>> > > > > > > >
>> >
>
>> > > >
>> >
>
>> > > > > >
>> >
>
>> > > >
>> >
>
>> > > > > > > > Any advice or clarity would be greatly
appreciated.
>> > > >
>> >
>
>> > > > > > > > Thanks,
>> > > > > > > > David
>> > > >
>> >
>
>> > > > > > > > Sent with ProtonMail Secure Email.
>> > > >
>> >
>
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>> > > > > > > > To unsubscribe send an email to
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>> > > > > > > >
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>> > > >
>> >
>
>> > > > > > > > List Archives:
>> > > >
>> >
>
>> > > >
>https://lists.ovirt.org/archives/list/users@ovirt.org/message/RGHCN356DXJEDR5FJ7SXSBHBF5FYRWIN/
>> > > >
>> >
>
>> > > > >
>> >
>
>> > > >
>> >
>
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