Questions on Disks

[Newbie009]

Hi all,

I have 4 quick questions for you:

1) From what I understand when you install vCenter Operations Manager you enter the datastore which will be the location of the install.

This datastore is then automatically used as the repository for all collected data.

Is it possible to configure the appliance with a separate datastore to store the data, separate from the appliance OS files or is it just one datastore for everything?

2) A client is asking if we can use Thin Provisioning for the disk where we will install vCenter Server Operations Manager.

I have read that this is not recommended but am I right in thinking that the only thing bad about this is that, if you install on a Thin Provisioned disk, there is the chance that you could install other VMs on the same datastore and use the space intended for the Op Mgr disk should it need to grow in the future?

That is it is more of a "you could do it but you need to be really careful" scenario/warning?

I ask because the LUN where they want to install it will be used solely for the appliance, no other VMs.

3) Is there a maximum recommended datastore size for this appliance or is is whatever you need?

I ask because VMware mentioned that, for the amount of data we wanted to collect, we would need aprox 1.8TB disk space.

IF we were to install in Thick Provisioning, is there any problem to install the appliance on a datastore that big?

4) Do the answers to the above 3 questions change with the version of vCenter Operation i.e. v1.0.1 and v5.0?

Any comments?

Thanks in advance

Mark

[Newbie009]

I should also mention that what we are doing with the client is just a demonstration of how the software works and a specific data-collecting exercise.

IF everything goes well and they like what they see, there is the option to install again on a more permanent basis and use Thick for the installation.

Thanks

[jddias · Accepted solution]

1) From  what I understand when you install vCenter Operations Manager you enter  the datastore which will be the location of the install.

This datastore is then automatically used as the repository for all collected data.

Is  it possible to configure the appliance with a separate datastore to  store the data, separate from the appliance OS files or is it just one  datastore for everything?

You could SvMotion Hard disk 2 on the VMs to another data store if you wanted to provide seperation.  What is your reasoning for doing this?

2) A client is asking if we can use Thin Provisioning for the disk where we will install vCenter Server Operations Manager.

I  have read that this is not recommended but am I right in thinking that  the only thing bad about this is that, if you install on a Thin  Provisioned disk, there is the chance that you could install other VMs  on the same datastore and use the space intended for the Op Mgr disk  should it need to grow in the future?

It is not recommended for performance reasons.  The virtual disks will be adding data rapidly for the first few months of operation and a thin provisioned VMDK would be constantly growing.  There is a write performance penalty when a thin provisioned disk needs to allocate more space.  That is the rationale for recommending eager thick disks.  Overprovisioning is another concern, as you stated.

3) Is there a maximum recommended datastore size for this appliance or is is whatever you need?

I ask because VMware mentioned that, for the amount of data we wanted to collect, we would need aprox 1.8TB disk space.

IF we were to install in Thick Provisioning, is there any problem to install the appliance on a datastore that big?

VMDKs can be up to 2TB (-512 bytes if anyone wants to be picky :smileysilly:) in size and you may have multiple.  I believe the file system will scale to 16TB max (based on ext3 and 4k blocks).  I would generally advise sticking with the sizing recommendations in the documentation and monitoring the free space.

4) Do the answers to the above 3 questions change with the version of vCenter Operation i.e. v1.0.1 and v5.0?

Yes, in particular for question 3 - you expand the existing hard disk 2 in 1.0.1 instead of adding another vmdk in 5.0.

[Newbie009]

Hi jddias,

Thanks for the quick reply.

Here are my comments to your questions:

1) I was just curious if it could be done as it appears that it can´t in the documentation.

2) I can understand your comments.

The client only needs to collect data for 1 month.

They are also reluctant to give me a LUN of nearly 2TB in size for a test.

I will mention what you said to them.

Thanks again, excellent answers.

Regards

Mark