OE database(s) on VMware: RDM or Eager Zeroed disks?

Posted by Jimmer on 05-Jun-2015 01:36

Dear Sirs,
In a VMware virtualized environment, are there concerns/preferences between putting the database on an RDM disk or Thick Eager Zeroed?
Mainly it is going to be one physical server with two guests maximum, one guest with the db and one with the application files, appserver,etc...
OS of each guest is on a separate Raid 1 set, with the database(s) on their separate disks and so for the application files.
No overcommitting of Ram or CPU resources and no snapshots of the db disks.
Since the disks are internal, there may be some checks to be done regarding whether they can be added as Raw disks on VMware, so can we go with Eager Zeroed instead if RDM is a dead end or we try Hyper-V (to see if we can add them as physical disks)

Thanks

JM

All Replies

Posted by Marie Candela on 09-Jun-2015 16:24

We don’t have any direct experience in Development with those configurations.  Hopefully someone out in the field can offer you some feedback.  The North Amercia PUG is going on this week, maybe after that’s over…
 
-Marie
 
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From: Jimmer [mailto:bounce-Jimmer@community.progress.com]
Sent: Friday, June 05, 2015 2:37 AM
To: TU.OE.RDBMS@community.progress.com
Subject: [Technical Users - OE RDBMS] OE database(s) on VMware: RDM or Eager Zeroed disks?
 
Thread created by Jimmer

Dear Sirs,
In a VMware virtualized environment, are there concerns/preferences between putting the database on an RDM disk or Thick Eager Zeroed?
Mainly it is going to be one physical server with two guests maximum, one guest with the db and one with the application files, appserver,etc...
OS of each guest is on a separate Raid 1 set, with the database(s) on their separate disks and so for the application files.
No overcommitting of Ram or CPU resources and no snapshots of the db disks.
Since the disks are internal, there may be some checks to be done regarding whether they can be added as Raw disks on VMware, so can we go with Eager Zeroed instead if RDM is a dead end or we try Hyper-V (to see if we can add them as physical disks)

Thanks

JM

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Flag this post as spam/abuse.

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Posted by Libor Laubacher on 09-Jun-2015 18:04

Is this brand new setup or are you going to re-use what’s on the existing disk drives ?
 
If this is a brand new setup, then go eager zeroed.
 
If you have a database already behind SAN on an existing LUN, I’d go RDM, as you would not need to do any migration, and by using RDM just plug an existing LUN in.
 
But judging from your description you aim to have 1 ESX host using internal drives, so go eager zeroed DS.
I am not sure I understand the remark about a need to add disks as ‘raw’ since they are internal. You can put a datastore onto an internal drive. RDM’s advantage is a) re-use of an existing data (behind an existing LUN), b) whatever backup/snapshot techniques were used on SAN for that LUN(s) can still carry on unchanged
You can technically use RDM for local drives with some tweaking, but there will be no benefit at all, only extra work.
 

Ø  Mainly it is going to be one physical server

 
Question tho – what are you going to do if this one server bursts up in the flames ?
You should at least have 2 hosts and use HA.
 
<shameless plugs>

Posted by Jimmer on 10-Jun-2015 07:16

Hi Libor,

It's a brand new setup, new servers, so no pre-existing data.

We were thinking RDM because we don't see the advantage of adding a virtualization layer to a relatively crowded environment (around 40 concurrently running databases, though mostly no heavy activity, just bug testing and dev, etc...) since we will not be using snapshots, nor VM replication. Why add a layer and worry about it? Unless I'm missing something :)

In all cases, the hardware doesn't seem to have the requirements for adding RDM in VMWare, so we're going Hyper-V with pass through (physical) disks for the databases, which tested fine.

Regarding the server bursting up in flames :), it is a risk, but we will have to rely on backups of the VM and the .p/.r programs (database data being irrelevant to a large extent).

One of the alternatives, since no SAN is involved we can use empty drive slots on another similar server and "continue" from there relatively easily since it is virtual.

But then again, for client deployments, if you had the two options (RDM and Eager Zeroed), with no pre-existing data, what would you choose for database, given you want the best performing environment with little to no compromise?

Thanks

JMR

Posted by Libor Laubacher on 10-Jun-2015 13:22

Jean-Marie,

Ø  But then again, for client deployments, if you had the two options (RDM and Eager Zeroed), with no pre-existing data, what would you choose for database, given you want the best performing environment with little to no compromise?

VMFS and eager zeroed VMDK.
 
I do not believe that fiddling with RDM onto local drives will give you a performance benefit (worth the trouble which is involved in setting this up).
 
/LL
 
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From: Jimmer [mailto:bounce-Jimmer@community.progress.com]
Sent: Wednesday, June 10, 2015 2:17 PM
To: TU.OE.RDBMS@community.progress.com
Subject: RE: [Technical Users - OE RDBMS] OE database(s) on VMware: RDM or Eager Zeroed disks?
 
Reply by Jimmer

Hi Libor,

It's a brand new setup, new servers, so no pre-existing data.

We were thinking RDM because we don't see the advantage of adding a virtualization layer to a relatively crowded environment (around 40 concurrently running databases, though mostly no heavy activity, just bug testing and dev, etc...) since we will not be using snapshots, nor VM replication. Why add a layer and worry about it? Unless I'm missing something :)

In all cases, the hardware doesn't seem to have the requirements for adding RDM in VMWare, so we're going Hyper-V with pass through (physical) disks for the databases, which tested fine.

Regarding the server bursting up in flames :), it is a risk, but we will have to rely on backups of the VM and the .p/.r programs (database data being irrelevant to a large extent).

One of the alternatives, since no SAN is involved we can use empty drive slots on another similar server and "continue" from there relatively easily since it is virtual.

But then again, for client deployments, if you had the two options (RDM and Eager Zeroed), with no pre-existing data, what would you choose for database, given you want the best performing environment with little to no compromise?

Thanks

JMR

Stop receiving emails on this subject.

Flag this post as spam/abuse.

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Posted by Jimmer on 15-Jun-2015 01:23

Ok, I got your point :)

Thanks Libor

Regards,

JMR

This thread is closed