Several Data ONTAP Edge Questions

[ Edited ]



I'm looking into using Data ONTAP edge and I have several questions about how the appliance works.


If I want to use the full 10 TB capacity, I have some questions on the recommended approach:

  • VMDK files are limited to 2 TB,  so do you just add 5 of them to the appliance?
  • Do you create a separate SCSI controller for each VMDK, or do you put them all on the same SCSI device on the virtual appliance?
  • What VMDK format do you use? (Thin, Thick lazy zeroed, eager zeroed thick)
  • Is the 10 TB limit the "usable" space after WAFL has been written to the disks?
  • Or is the 10 TB limit the amount of raw space (VMDK files) you can attach to the appliance?


Some questions around the underlying disks in the physical server:

  • Is there a recommended RAID level to use for the local disks in the physical server?  (RAID 5, 6, etc)
  • I plan on having at least 12 x 900 GB SAS drives in the server
    • Do I create 1 big RAID group and 1 big VMFS volume?
    • Do I create smaller RAID groups and VMFS volumes for each of the VMDKs?
    • What is recommendation for the underlying disks RAID config?
  • Is there a supported servers/disks list?


Some questions around the virtual appliance config and performance:

  • I think the base appliance has 2 vCPU and 4 GB of RAM.  If I give it more, will it take advantage of it?
  • For example, if I give it more RAM, will the appliance have more "cache"?
  • Same question for CPU, does giving the appliance more vCPU's give it more processing power?


I know it's a lot of questions.  But I can't seem to find the answers for them in any of the marketing material I've been reading.


Thanks in advance.

Re: Several Data ONTAP Edge Questions

Well...  I've not got much response, but I have figured out a few of the answers so I thought I would share.  It seems I just need to test some of this and blog about it.  (if only I had time)

What is the maximum usable storage?

The Data ONTAP Edge family supports up to 10TB of storage capacity. The usable limit is impacted by a few factors:

  • Overhead imposed by VMware (about 233GB for a 10TB system)
  • WAFL reserve (1007GB for the root volume alone)
  • Snapshot space (initially zero, since the root volume disables Snapshot copies by default)

Data ONTAP Edge configured with 10TB of storage will boot up and show "usable space" as 9071GB. This means that you can create a volume of 8990GB that, when the WAFL reserve is taken into account, results in 8540GB of free space for data and Snapshot copies. Reducing the WAFL reserve can increase the amount of usable space, as does disabling Snapshot copies. NetApp does not recommend either for most situations.

The configuration of the RAID card determines how much raw disk space is required to deliver a specific quantity of usable storage. For example, RAID 1 (mirroring without parity) needs 20TB of raw storage to deliver 10TB of usable storage. Contact your NetApp representative for more information.

What drives does Data ONTAP Edge support?

Answer: Data ONTAP Edge uses virtual machine disks (vmdks) passed to it by the hypervisor. It then uses RAID 0 (pass-through) on the vmdks and creates the aggregate. Due to using vmdks, the drive details are abstracted from the virtual machine. Therefore, any underlying drive type is supported.

Can Data ONTAP Edge support a server with more than one RAID controller?

Answer: Yes. The hypervisor abstracts the drive environment through the VMware file system such that Data ONTAP Edge sees only a virtual disk. The vmdk information passed to the virtual machine does not distinguish from where the disks come.

Can the settings for the virtual machine be changed?

Answer: The Data ONTAP-v virtual machine reserves two CPU cores and 4GB of RAM from the host. You cannot change these settings; if you do, the storage system will not boot. Limiting resources is not supported and has not been tested. It can negatively impact the I/O capability of the storage system and can risk data loss.

After installing the Data ONTAP Edge virtual machine, a 100% CPU utilization warning is reported by vSphere. Why?

Answer: Data ONTAP-v does not release the CPUs when idle. So, vSphere reports a high CPU warning because it sees 100% usage. You can ignore or clear the vSphere alarm for CPU usage. The Data ONTAP sysstat command displays the true usage of the CPUs.

What VMDK format do you use? (Thin, Thick lazy zeroed, eager zeroed thick)

Select the disk format Thick Provision Lazy Zeroed to store the virtual machine virtual disks

What are the basic requirements for a Data ONTAP Edge deployment?

Answer: Data ONTAP Edge server requirements are as follows.

  • Enterprise-class x86 server with a minimum of 8GB memory
  • VMware vSphere version 4.1 U2, 5.0 or higher
  • Hardware RAID with battery-backed cache

Internal drives connected to a RAID controller

Supported servers are listed on the IMT. (Netapp’s Interoperability Matrix)

Data ONTAP Edge deployments require a connection (via SnapVault) to an existing FAS or V-Series storage system. Standalone Data ONTAP Edge deployments are supported with Data ONTAP Edge-T.

What are the hardware requirements?

Answer: Data ONTAP-v runs on most x86 enterprise-class servers. It requires two virtual CPUs, 4GB of memory, and a hardware RAID controller with battery-backed cache. The type, physical size, and location (internal or external) of the managed disk do not matter (as defined in the Interoperability Matrix). The VMware vSphere hypervisor and Data ONTAP-v virtual machine must be read from datastores that are not part of the managed storage array

How much and what kind of storage is supported?

Answer: The maximum storage capacity is 10TB. This number is post-RAID since the RAID functionality is provided via the hardware.

Data ONTAP-v does not provide RAID