Informix High Availability
Someone asked whether to build Informix high availability on physical hosts with HDR/SDS or on VMware using vMotion. Opinions were mixed: one poster favoured VMware as more transparent and lower-level, while most preferred Informix-native HDR because the engine caches much in memory, secondary takeover is faster, and HDR only ships logical logs rather than all pages, physical log, temp and sort space. Others suggested combining HDR with a cluster manager, and warned of VMware's extra virtualisation layer, performance overhead, harder debugging, hypervisor bugs during live migration, and a crash seen when snapshotting during an ontape backup. No single conclusion was reached.
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Hello all, I am doing Informix HA Implementation research between "Physical Host + Informix + HDR/SDS" vs "VMWare + Informix + vMotion" Whats your bet and why ? Thanks --001a11c3d08c374d8b051fa1c667
VMWare, because its more transparent and takes place at a lower level. > On 13 Sep 2015, at 15:29, KN Liew Liew <liewkn@gmail.com> wrote: > > Hello all, > > I am doing Informix HA Implementation research between "Physical Host + > Informix + HDR/SDS" vs "VMWare + Informix + vMotion" > > Whats your bet and why ? > > Thanks > > --001a11c3d08c374d8b051fa1c667 > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. >
I'm a big fan of Informix HDR. No generic ha solution will make me comfortable since I formix keeps lots of data in memory. Recovery of an HDR secondary to take over from a failed promary will always be faster than recovering an HA copy. Art On Sep 13, 2015 10:29 AM, "KN Liew Liew" <liewkn@gmail.com> wrote: > Hello all, > > I am doing Informix HA Implementation research between "Physical Host + > Informix + HDR/SDS" vs "VMWare + Informix + vMotion" > > Whats your bet and why ? > > Thanks > > --001a11c3d08c374d8b051fa1c667 > > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > --001a113ecb5a89f76d051fa4042f
I would go for a combination of the 2 since the Informix replication thru HRD is great and specialized in the management of databases and HA environments have a broader view of things. You probably have other things running on your system in relation with your databases and may be also other things that are not directly in relation with the database engine. I do not have experience with vMotion but have advised and setup HA environments on IBM Power Systems using Informix HDR to take care of the Informix engine part (and all of the databases in the instance) together with IBM PowerHA for all of the things around the engine (launching scripts, batches, supersion, applications, etc) and this works great. Cordialement, Regards, Khaled Bentebal Directeur Général - ConsultiX Tél: 33 (0) 1 39 12 18 00 Fax: 33 (0) 1 39 12 18 18 Mobile: 33 (0) 6 07 78 41 97 Email: khaled.bentebal@consult-ix.fr Site Web: www.consult-ix.fr Le 13/09/15 16:29, KN Liew Liew a écrit : > Hello all, > > I am doing Informix HA Implementation research between "Physical Host + > Informix + HDR/SDS" vs "VMWare + Informix + vMotion" > > Whats your bet and why ? > > Thanks > > --001a11c3d08c374d8b051fa1c667 > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > >
What is my bet on what? VMWARE adds an extra layer. Performance will be marginally worse to much = worse, overall. The biggest problem is people using VMWARE/etc in = productions haven=92t gotten to the point yet where they run diagnostics = on the VM.=20 We are still in a traditional mindset when the problem (from an = infrastructure standpoint) is either the The DB, the OS, or rate = hardware. One of the biggest current overlooks its that for every = Databse Write, we no longer have=20 DB Disk write -> OS writes -> Physical Disk Subsystem write. We have DB Disk Write -> OS write -> VM Write -> Physical Disk Subsystem write.=20= That is one more level of indirection, and It not only has an extra cost = (resulting in some minor performance hit) but it also means an extra = layer of debugging necessary if you have a problem. And Keep in mind that while I listed the issue for disk, with a VM it is = everything.=20 Memory, Disk, Network, CPU. All 4 components have to go through the VM = Layer to process.=20 Oh AN VMOTION is another area where bugs can result in nasty situations. = In order to do a =93hot failover=94 you have to be able to fully manage = all OS registers and Virtual CPU registers, in real time. If you miss = your window you can watch your Database, or any other application using = the in transit register, crash hard. I worked with a customer that saw = exactly that until their Hypervisor was patched.=20 Now keep in mind that VMWARE brings some very nice features, and = provides you the opportunity of partitioning a very large bare metal box = to logically represent a bunch of machines, but don=92t expect better = performance out of it.=20 You are taking a performance hit for the flexibility that VMWARE + = vmotion provides. Just remember nothing comes without a cost. :-) -Mark On Sep 13, 2015, at 9:29 AM, KN Liew Liew <liewkn@gmail.com> wrote: > Hello all,=20 >=20 > I am doing Informix HA Implementation research between "Physical Host = +=20 > Informix + HDR/SDS" vs "VMWare + Informix + vMotion"=20 >=20 > Whats your bet and why ?=20 >=20 > Thanks=20 >=20 > --001a11c3d08c374d8b051fa1c667=20 >=20 >=20 > = **************************************************************************= *****=20 > Forum Note: Use "Reply" to post a response in the discussion forum.=20= >=20
And I have seen an interesting VMware bug with larger Informix Windows
installation (~1.5TB), if you take a VMware snapshot at the same time as you
take an ontape backup the VMServer crashes i.e the physical server crashes
Cheers
Paul
-----Original Message-----
From: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org] On Behalf Of Mark
Jamison
Sent: Monday, September 14, 2015 9:48 AM
To: ids@iiug.org
Subject: Re: Informix High Availability [35783]
What is my bet on what?
VMWARE adds an extra layer. Performance will be marginally worse to much =
worse, overall. The biggest problem is people using VMWARE/etc in =
productions haven=92t gotten to the point yet where they run diagnostics =
on the VM.=20
We are still in a traditional mindset when the problem (from an =
infrastructure standpoint) is either the The DB, the OS, or rate =
hardware. One of the biggest current overlooks its that for every =
Databse Write, we no longer have=20
DB Disk write -> OS writes -> Physical Disk Subsystem write.
We have
DB Disk Write -> OS write -> VM Write -> Physical Disk Subsystem write.=20=
That is one more level of indirection, and It not only has an extra cost =
(resulting in some minor performance hit) but it also means an extra =
layer of debugging necessary if you have a problem.
And Keep in mind that while I listed the issue for disk, with a VM it is =
everything.=20
Memory, Disk, Network, CPU. All 4 components have to go through the VM =
Layer to process.=20
Oh AN VMOTION is another area where bugs can result in nasty situations. =
In order to do a =93hot failover=94 you have to be able to fully manage =
all OS registers and Virtual CPU registers, in real time. If you miss =
your window you can watch your Database, or any other application using =
the in transit register, crash hard. I worked with a customer that saw =
exactly that until their Hypervisor was patched.=20
Now keep in mind that VMWARE brings some very nice features, and =
provides you the opportunity of partitioning a very large bare metal box =
to logically represent a bunch of machines, but don=92t expect better =
performance out of it.=20
You are taking a performance hit for the flexibility that VMWARE + =
vmotion provides.
Just remember nothing comes without a cost. :-)
-Mark
On Sep 13, 2015, at 9:29 AM, KN Liew Liew <liewkn@gmail.com> wrote:
> Hello all,=20
>=20
> I am doing Informix HA Implementation research between "Physical Host =
+=20
> Informix + HDR/SDS" vs "VMWare + Informix + vMotion"=20
>=20
> Whats your bet and why ?=20
>=20
> Thanks=20
>=20
> --001a11c3d08c374d8b051fa1c667=20
>=20
>=20
> =
**************************************************************************=
*****=20
> Forum Note: Use "Reply" to post a response in the discussion forum.=20=
>=20
****************************************************************************
***
Forum Note: Use "Reply" to post a response in the discussion forum.
If you do HDR, then the network between the primary and the secondary is only dealing with the transfer of the logical logs. If you do anything requiring disk mirroring in any form (including VMWare motiong), then you also have to transfer the updated page, the physical log, any temporary tables, any sort space as well. Mpruet Now Retired...
Congratulations on your retirement. Don't be a stranger. --EEM > -----Original Message----- > From: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org] On Behalf Of > MADISON PRUET > Sent: Saturday, October 03, 2015 20:42 PM > To: ids@iiug.org > Subject: Re: Informix High Availability [35824] > > If you do HDR, then the network between the primary and the secondary > is only dealing with the transfer of the logical logs. If you do > anything requiring disk mirroring in any form (including VMWare > motiong), then you also have to transfer the updated page, the physical > log, any temporary tables, any sort space as well. > > Mpruet > Now Retired... > > > *********************************************************************** > ******** > Forum Note: Use "Reply" to post a response in the discussion forum.