Space of SimpliVity & Vmware

[Engsys_SP]

I have a question  about free space.

I facing with alert "No space remaining. Free up space by deleting unnecessary or old backups."  I want to create add new serrver but i'm concerned affect VMs shutdown.

I'm having confuse distinguishing between vmware's datastore and simplivity's space. it what effect do it have when i create new VM?

Please help me! Thanks you so much.

[egoqed]

dear canonVN

So your question is: Why do you have different amount of free space in the cluster overview and the cluster space summary?

Well, there are a few things to consider regarding space allocation but first, what kind of setup do you have ?
1.8:1 dedup ration seems extremely bad . How many host you have i your cluster mentioning?

You have somewehre around 55 TB combined storage and only 4.2 of it left. So, it makes sense to consider what to do next. As you are way over 80% and should already got an alert regarding remaining space.

Now back to your question. As SVT does thin provisioning you can in theory create extream big storages as datastores (as you probably did). You created more storage than you have which is called over provisioning.

This can work but is dangerous as you can completely fill up your hosts. 

Thin provisioing does only consume space you have "spent" regardless of how big your virtual disks are. Whereas thick provisioning "reservers" the requested storage.

So long story short. the picture you see on vmware on the host or cluster sais nothing about your effetive storage. Alway take a look on "monitor" and storage efficientcy and check logical and physical storage...

let's start with this. ask if you need more information.

cheers egoQED

[Engsys_SP]

@egoqed  thank for your reply.  We have 4 nodes in my cluster, it using deduplication 1:9:1.  I understood my problem . Howerve I want to know detail between 2 type space showed in my srceenshot. how can I calculate the HPE simpliVity space? Storage VMware is reporting 83TB but physical space HPE simpliVity is 55TB. why this difference?

[egoqed]

the physical space which HPE shows you, is the effective storage you have. But be aware that all VM have 2 replicas. So if you create a 1TB VM, you will spend 2TB on the storage.

The amount you see in the VMware screen is the combined storage you have in your "datastore" (DS) tab.

for example you have made a DS with 10TB, so you will see 10 tb on the cluster and around 270GB per node (the local storage of the back drives where your ESXi OS is running).

So, you should have either muliple DS which have a combined storage of the value you see. Or maybe you have only one big DS with the size you see.

btw. i would not create to big storages, a few smallers are better to handle. One of our 4node clusters looks like this:

 You see the dedup ratio, that's why I was a bit surprised...

On this cluster I only see 15TB in the VMware vCenter overview, as I only have 2 DS with 8TB and 7TB.

You see the relation between?

cheers

[Engsys_SP]

@egoqed  all VM have 2 replicas- this is default feature of simplivity, right? -->Is there an exception when i want some of my VMs in the cluster to not have replica? can I create datastore not in HPE simpliVity Federation? 

[egoqed]

Yes, the 2 repl. is the standard way SVT does things. You can create a single replica storage and do a storage move of certain VMs so you have only one. BUT, if something happens with the host which holds this sing.rep. DS...your Data is lost.

"I create datastore not in HPE simpliVity Federation? " Not quite sure what you mean. If you want to have the functions of SVT you have to create the DS within the Federation/Datacenter/Cluster. 

In theory you could use other NFS shares and mount them into the Fed, but that is highly experimental and only for test lab environments....nothing you want to have in a productive env.

[Sanika]

Hi @Engsys_SP 

VMware Datastore is the logical storage space presented to VMware vSphere for hosting VMs.  It does not account for SimpliVity's backend optimizations (dedupe and compression).
SimpliVity space reflects the actual amount of physical storage consumed in the SimpliVity environment after applying deduplication, compression and optimization.

Because HPE SimpliVity's data deduplication technology identifies and eliminates redundant data, logical capacity used is typically larger than physical capacity due to the reduction in data footprint.

And yes, HPE SimpliVity's default feature is to maintain 2 replicas of data for all VMs in the cluster. This ensures high availability and data redundancy.
Also, datastores in HPE SimpliVity are designed to be managed within the federation and are accessible only to HPE OmniStack hosts in the same cluster.
However, you can create and use standard vSphere datastores if you need storage options that aren't managed by the HPE SimpliVity Federation. These datastores won't have the same data efficiency and resiliency features, but they can be used for other purposes within your environment.

For more information regarding VMware's datastore (logical capacity) and Simplivity's space (physical capacity), you may refer to the below videos:

HPE SimpliVity - Logical and Physical Capacity
https://support.hpe.com/hpesc/public/videoDisplay?videoId=vtc00030455en_us

HPE SimpliVity - Monitor HPE SimpliVity storage efficiency
https://support.hpe.com/hpesc/public/videoDisplay?videoId=vtc00030429en_us

Hope this helps.

Regards,
Sanika.

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[Engsys_SP]

@egoqed how to create single replica storage, can you tell me the details?  The existing datastore will change to single replica storage, right?

[Sanika]

Hi @Engsys_SP 

To know about single replica and dual replica datastores, you can refer to the topic "Manage datastores" in the HPE OmniStack Administration Guide.
https://support.hpe.com/hpesc/public/docDisplay?docId=dp00003638en_us&docLocale=en_US

Also you may refer to this video "HPE SimpliVity - Creating a single-replica datastore"
https://support.hpe.com/hpesc/videoDisplay?videoId=vtc00030010en_us

Regards,
Sanika.

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[Engsys_SP]

@egoqed about deduplication methods, 

Could you analyze this method more carefully?

As far as I know, there are two methods of deduplication. What method do you think I'm using?

[Engsys_SP]

@Sanika  thanks for your information. 

" You cannot change the datastore's replica type after you create the datastore. For example, you cannot convert a single-replica datastore to a dual-replica datastore
You can move a single-replica virtual machine from a single-replica datastore to a dual-replica datastore, making it a dual-replica virtual machine."

I confuseed that comments in the HPE OmniStack Administration Guide. This mean that can not change datastore from single-replica datastore to dual-replica datastore and vice versa after created, right? how to move a single-replica virtual machine from a single-replica datastore to a dual-replica datastore?

[Sanika]

Hi @Engsys_SP 

Yes, you're right. According to the statement given in the guide, you cannot change datastore from single-replica datastore to dual-replica datastore after the datastore is created.

To move a single-replica virtual machine from a single-replica datastore to a dual-replica datastore, you may run the below command:
svt-vm-move --source <name of the origin datastore> --vm <name of the virtual machine> --cluster <name of the target cluster> --destination <name of the target datastore>

Please note, you cannot move a virtual machine from a dual-replica datastore to a single-replica datastore.

For more information on this, you may refer to the video "HPE SimpliVity - Moving a Virtual Machine using CLI"
Link - https://support.hpe.com/hpesc/videoDisplay?videoId=vtc00030317en_us

also, you may refer to the command "svt-vm-move" in the "Virtual machine commands" section in the command reference guide
Link - https://support.hpe.com/hpesc/public/docDisplay?docId=sd00005170en_us

Hope this helps.

Regards,
Sanika.

If you feel this was helpful, please click the KUDOS thumb below. Also consider marking this as an "Accepted Solution" , if the post has helped to solve your issue.