ChevUribe
Expert
Expert

Hybrid Flash Storage

Just like in a VSAN environment, If I have a typical VMware environment who is residing on a hybrid flash storage; can I configure that the SSDs will be the one for cache and the SATA/SAS disks are for storage?

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13 Replies
npadmani
Virtuoso
Virtuoso

if you manually mark SSHD as SSD storage and use that as your cache in VSAN disk group. It will work. So answer to your question is 'Yes', if you wish, you can do that in a test/training environment.

But in production environment, you want real SSD for caching so you get actual SSD performance and also you want your environment to be Supported. Above scenario is not going to be a supported scenario.

Storage requirements

  • For Caching:
    • At least 1 SAS/SATA Solid State Drive (SSD), or a PCIe flash disk.

Ref: VMware Virtual SAN 6.0 Requirements (2106708) | VMware KB

Narendra Padmani VCIX6-DCV | VCIX7-CMA | VCI | TOGAF 9 Certified
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ChevUribe
Expert
Expert

what I mean is can we do the similar thing if we are not using VSAN?

Can I have for example an EMC SAN hybrid flash storage. The SSDs will be for Cache and the SATA/SAS will be for capacity?

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npadmani
Virtuoso
Virtuoso

oh yes, why not?

We have Storage based Tiering and Caching mechanism available from almost all the storage vendors.

Take a quick look at following post which will answer you question in a great detail.

Tiering vs. caching in flash-based storage systems

aso refer

EMC Square ISM book

http://www.amazon.com/Information-Storage-Management-Managing-Protecting/dp/0470294213?ie=UTF8&*Vers...

Narendra Padmani VCIX6-DCV | VCIX7-CMA | VCI | TOGAF 9 Certified
ChevUribe
Expert
Expert

From my understanding, the SSD as cache and SAS/SATA as capacity configuration will be done in the storage side.

Will this configuration be transparent to VMware? Will VMware be intelligent enough that if we put the VMs on that SSD/SAS LUN, it will use the SAS for the capacity?

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RanjnaAggarwal
VMware Employee
VMware Employee

Hi,

If the SSD and HDDs are configured from the Storage side like which one is for storing the data and for caching that esxi will never come to know. But there is an option to configure the flash read cache feature at esxi level if you are using this feature apart from your storage configuration then yes you can configure particular ssd for the flash read cache feature.

Regards, Ranjna Aggarwal
RanjnaAggarwal
VMware Employee
VMware Employee

I hope this answers your query.

Regards, Ranjna Aggarwal
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ChevUribe
Expert
Expert

@RanjnaAggarwal

May I knnow what option is this in the ESXI hosts?

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RanjnaAggarwal
VMware Employee
VMware Employee

Check this article:-

http://www.vladan.fr/vmware-vflash-read-cache-vfrc-configuration/

Regards, Ranjna Aggarwal
ChevUribe
Expert
Expert

Oh I can see, this is similar to VSAN without the VSAN license.

Its only limitation is it should be a local SSD.

I'm thinking if this can also be done on a SAN storage Smiley Sad

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RanjnaAggarwal
VMware Employee
VMware Employee

In SAN devices no need to configure anything as vmware admin, san devices have ssd for caching

Regards, Ranjna Aggarwal
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ChevUribe
Expert
Expert

Yes it can be figured on the storage side, but as discussed earlier if I am correct; ESXI hosts will never know that the SSDs are already used for caching.

VMs will never utilize that unlike the procedure you gave to me.

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RanjnaAggarwal
VMware Employee
VMware Employee

yes, esxi will never know this part as i mentioned earlier it is not going to be visible to esxi.

Regards, Ranjna Aggarwal
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npadmani
Virtuoso
Virtuoso

From my understanding, the SSD as cache and SAS/SATA as capacity configuration will be done in the storage side.

Will this configuration be transparent to VMware? Will VMware be intelligent enough that if we put the VMs on that SSD/SAS LUN, it will use the SAS for the capacity?

if storage array level tiering is done,then we will read those capabilities at vcenter-esxi end by the use of VASA provider, and use those in Storage Profiles, that's how it gets managed. in short, it becomes profiled driven storage management for VM placements.

Ref:

vSphere Storage APIs - Storage Awareness FAQ (2004098) | VMware KB

Narendra Padmani VCIX6-DCV | VCIX7-CMA | VCI | TOGAF 9 Certified
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