Nimble Space discrepancy

[Niveda]

Hi,

We see space discrepany in Nimble and the VMware and theres a lot of difference in the free space and allocated

• On VMware        we see 20 TB free / allocated 37 TB
• On Nimble           we see 85 TB free / used 7 TB

I am aware that compression ,deduplication and thin provisioning does a lot of saving but I would like to understand if Storage can be over allocated at times because the actual and the logical space isnt same?

Also can the savings make this huge difference? Are we missing anything at the VMware ?

[Satish04]

Hi Niveda,

Yes, the difference in free and allocated space between VMware and Nimble storage can be attributed to various factors
such as thin provisioning, deduplication, and compression.

Thin Provisioning: Thin provisioning allows you to allocate more logical storage space to virtual machines in VMware than what is physically available on the Nimble storage array.
This means that the allocated space reported by VMware can be larger than the actual physical capacity of the Nimble array. Thin provisioning enables more efficient
utilization of storage capacity by allocating space on-demand as the virtual machines require it.

Deduplication: Nimble storage arrays often employ data deduplication techniques to reduce storage space consumption by eliminating redundant data blocks.
Deduplication identifies duplicate data blocks across multiple virtual machines or within a single virtual machine and stores only one instance of each unique block.
This can lead to significant space savings, especially if there are similarities or repetitive data patterns among the virtual machines.

Compression: Compression is another data reduction technique used by Nimble storage arrays.
It reduces the size of data blocks by encoding them in a more compact form.
Compressing the data further reduces the storage space required to store the virtual machines.

These storage efficiency technologies (thin provisioning, deduplication, and compression) can result in substantial savings in storage space utilization.
The reported free space on the Nimble storage array reflects the post-data reduction savings,
which may explain the significant difference between the free space reported on Nimble and the allocated space reported on VMware.

It's important to note that the reported space usage in VMware is based on the logical size of the virtual disks allocated to the virtual machines, while the reported space usage on the Nimble array reflects the physical storage consumed after data reduction techniques have been applied. This can account for the discrepancy between the two.

To ensure accurate reporting and understanding of your storage utilization, it's recommended to consider both the logical space allocation in VMware and the physical space consumption on the Nimble storage array. 

Hope this helps.

Regards,

Satish

[Mahesh202]

Hi Niveda

The discrepancy you're observing between the space reported in VMware and on the Nimble Storage system can be attributed to several factors, including thin provisioning, compression, deduplication, and other storage optimization techniques. 

1. Overallocation: Yes, storage systems, including Nimble Storage, often employ thin provisioning, which allows for the allocation of more logical capacity to virtual machines (VMs) than the physical capacity available. This means that the logical space allocated to VMs in VMware may exceed the actual physical capacity of the storage system. Thin provisioning helps optimize storage utilization by allocating physical capacity on-demand as data is written.
2. Storage savings: Compression, deduplication, and thin provisioning can result in significant storage savings. Compression reduces the size of data by encoding it in a more compact form, while deduplication identifies and eliminates duplicate data. Thin provisioning ensures that physical capacity is allocated only when data is written, rather than pre-allocated for the entire logical capacity. These techniques can lead to substantial differences between the logical space reported in VMware and the actual physical space consumed on the Nimble Storage system.

It's important to note that the reported free and allocated space in VMware is based on the logical provisioned size, while the free and used space on the Nimble Storage system reflects the actual physical utilization. The difference between the two can be quite significant due to the benefits of compression, deduplication, and thin provisioning.

To ensure accurate visibility of storage utilization, it's recommended to monitor the capacity and usage metrics provided by the Nimble Storage system itself. This will give you a more accurate representation of the physical space consumed and available on the storage array.

Additionally, it's advisable to review the specific configuration and settings of your VMware environment to ensure that thin provisioning, compression, and deduplication features are appropriately configured and accounted for in your capacity planning.

Hope this helps.!!

Regards
Mahesh.

[Sunitha_Mod]

Hello @Niveda,

Let us know if you were able to resolve the issue.

If you have no further query and you are satisfied with the answer then kindly mark the topic as Solved so that it is helpful for all community members.