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Dual controller for dual VSA question

lmaximo
Occasional Advisor

Dual controller for dual VSA question

Hi to all and sorry for my English,

i would buy and configure one DL380G8 with one P420i controller and 16x256GB  SSD Disk.

I need to share this server between two company and therefore install on it two VSA 1TB Free.

Here my question:

Esxi on SD card or dedicated HDD/SDD

First VSA in first array RAID 10 with 8xSSD

About second VSA? Can we install it in a second array managed by the same controller or make sense to add a second 420i controller for the second array so that the two array are managed separately with goal of performance improvement?

I hope that my explanation is clear and that nothing is missed.

Thanks in advance for your help/suggestion about this configuration.

Best regards.

Massimo

 

11 REPLIES
oikjn
Honored Contributor

Re: Dual controller for dual VSA question

This seems overly complicated.  A single VSA used by itself does not provide anything special and is not worth the extra complications IMO.  what are these two individual VSA's serving data for?  

Is the host going to have any other VMs on it or is it just going to have the two VSA VMs?

lmaximo
Occasional Advisor

Re: Dual controller for dual VSA question

Hi Oikjn and thanks for your reply.

Please, can you explain "A single VSA used by itself does not provide anything special"? Thanks for this.

The two VSA will be used as iSCSI target by other two different Esxi server.

So, finally, we would have:

First Esxi server that use first VSA as iSCSI target

Second Esxi server that use second VSA as iSCSI target

Third Esxi server (object of this post) that contain/run only the two VSA.

I hope to be more clear now.

Thanks again

Massimo

 

oikjn
Honored Contributor

Re: Dual controller for dual VSA question

the only advantage the VSA solution has is its redundancy around the network raid setup.  having a single VSA running by itself completely negates that advantage.  You would be better off using a DAS shelf between the two hosts instead of a third host running two VSAs.  a "Normal" setup with two VM hosts would be to run a VSA instance on each host and then connect them as a single cluster.  This would provide the redundancy where you could restart either host or either VSA node and maintain system availability.  The only drawback to this is that you would require 2x the raw storage capacity.  Also keep in mind that the VSA itself doesn't provide hardware raid support to the underlying drives, so you have to provide it to the VSA as such and that means you need a hardware raid card on the host.  

 

I still don't understand your isolation you were thinking you were trying to achieve.  with two ESX hosts and two VSAs each serving their own host, If that is the case, why not just have internal harddrives serving the data to each host?

lmaximo
Occasional Advisor

Re: Dual controller for dual VSA question

Hi Oikjn and thanks again for your time.

You are absolutely right and i apologize but i missed some information because we would reach the redudancy goal in a second time.

Basically our "final goal" is to have the redundancy of the two VSA in another host esxi in equal configuration.

So, finally, but after some months from here, we will hope to have:

First Cluster of two or more Esxi server that use first VSA as iSCSI target

Second Cluster of two or more Esxi server that use second VSA as iSCSI target

First other Esxi server (object of this post) that contain/run only the two VSA.

Second other Esxi server for HP VSA Fault tollerance VM

Third other Esxi server (exactly equal to this object of this post) that contain/run two VSA as redundancy of the the two previous  VSA

About a minimum of 7 esxi server in final configuration

The choiche of run two VSA in the same host have only goal to optimize the usage of hardware host and to avoid to have one host for each VSA.

If my solution "can work" i will have all redundancy with two esxi host instead that with four host.

I hope to be more clear now.

Thank again.

Massimo

Bart_Heungens
Honored Contributor

Re: Dual controller for dual VSA question

Hi Massimo,

I keep on reading your explanation and really don't get what you try to achieve...

First of all your statement "First Esxi server that use first VSA as iSCSI target, Second Esxi server that use second VSA as iSCSI target" doesn't make any sense. You cannot connect to a VSA as iSCSI target.

When you deploy a VSA solution you will deploy a minimum of 2 VSA's on 2 different servers. These 2 VSA's will form a cluster with a virtual IP address configured accros those 2 VSA's. Your iSCSI target will be the cluster of 2 or more VSA's, not the VSA itself... You can create a cluster with 1 VSA which does not make any sense (like Oikjn mentioned), because that would be a DAS solution...

You install 2 VSA's on 2 different servers since the VSA will replicate all data accros those 2 servers for redundancy on the server level, the server is not a single point of failure anymore.

When you deploy 2 VSA's on 1 physical server you will need to assign 2 capacity blocks to each VSA and have it replcated to each other. The data is replicated on 2 different disks BUT the server is still a single point of failure...

Other quote from you: "Second other Esxi server for HP VSA Fault tollerance VM". Let it be clear that you cannot VMotion a VM (since it is using local storage), you don't make a backup of a local VSA (doesn't make any sense since it is replicated to another VSA anyway on another server), and we definitely not gonna put Fault Tolerance on the VSA... THe VSA itself is already replicating its data through Network RAID, why do you want VMware to have the VSA replicated as well?

If you have in mind 7 servers, why not put the VSA's accros several servers? You will get more bandwidth on network level so a better performance anyway...

Kr,

Bart

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lmaximo
Occasional Advisor

Re: Dual controller for dual VSA question

Hi Bart,

and thanks for your reply. I understand that my bad explanation in a language of which I'm not fully master has become a terrible result. I apologize for this and try again with hope not to disturb anyone.

From the scratch: I would like to achieve an iSCSI target that will be a cluster of 2 (or more) VSA's with his virtual IP. This cluster will be formed between two VSA running on two different Esxi server. I already know this and I took this for granted creating accordingly a lot of confusion.

Now, to make the most of the hardware of these two Esxi server, can i form another totally different cluster (installing other two VSA) together with the aforementioned ones?

Therefore:

Esx01 with VSA01CLUST01 and VSA01CLUST02

Esxi02 with VSA02CLUST01 and VSA02CLUST02

I would like to achive two totally different VSA cluster using the same hardware and obtaining the most usage of hardware other then high availability.

I hope to be clear in this my last chanche... :-) :-)

Best regards and thanks again.

Massimo

Bart_Heungens
Honored Contributor

Re: Dual controller for dual VSA question

Hi Massimo,

OK this makes more sense. And yes you can install 2 VSA's on 1 server for creating 2 clusters... However, can you tell me the reason why you want to clusters? You state that you obtain the most usage of hardware? Why can't you do this with one VSA?

Performance wise I would suggest 2 RAID controllers, 1 for each VSA. But these 2 VSA's will still use the same network cards... Or do you want to install dedicated NIC's as well? The entire setup will be way more expensive for the little gain you will obtain.

Also when you have 2 RAID controllers you have 2 RAID sets so 2 times RAID overhead... So price per GB will be higher...

THe only reason I can imagine is that you want to create an all-flash cluster and a SAS cluster? Even then you don't have the best usage of the hardware... You will still have to decide which data will be on the SSD model and the SAS model... Growing those 2 clusters will be less efficient either instead of choosing 1 big cluster with SSD and SAS with tiering enabled... And for those volumes wanted on SAS you can disable tiering per volume...

So technically yes you can... But I still don't get the message you obtain the most usage of hardware... This can be with a single VSA per server, this is at least how I do it for my +100 customers with VSA...

Kr,

Bart

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lmaximo
Occasional Advisor

Re: Dual controller for dual VSA question

Hi Bart,

I'm happy that now is more clear. :-)

>>Why can't you do this with one VSA?

Only because, on this way, I can install two (one for company) free VSA 1 TB cluster, avoiding the purchase of two expensive 4TB licenses that, leaving aside the economic factor, would be too big for what was necessary.

>>Or do you want to install dedicated NIC's as well?

Yes, sure. In my idea, adding necessay SDD to unused bays, necessary NICs and 1 additional controller, I avoid to add another dedicated esxi host and would use at most the existing one that have dual processor and 16 or 32GB of ram.

>>But I still don't get the message you obtain the most usage of hardware...

Based on this my clarifications (i hope) you think that this can be a good idea?

Differently from you, this is my first experience with VSA and "coming" from many QNAP (879 or higher) SSD RAID 5 equipped i have only a theoretical idea how much I will gain in performance and efficiency (in addition to HA).

Thanks.

Regards.

Massimo

Bart_Heungens
Honored Contributor

Re: Dual controller for dual VSA question

Hi Massimo,

If you know the weaknesses of the 1TB free license (no support, no updates, nothing whatsoever) then yes you can make the configuration you had in mind...

But I am not convinced that the additional NICs, controllers, RAM, better CPU, tweaking of the system and the time that you will put in there will be cheaper than the 4TB license pack... Know that in the 4TTB license pack you get 3 licenses for 3 VSA's... Including tiering to SSD's...

To answer your question: yes you can do it technically, will you get more performance and more HA? Quite sure no unless you know what you are doing, and it will be more expensive for sure...

Kr,

Bart

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lmaximo
Occasional Advisor

Re: Dual controller for dual VSA question

Hi Bart,

based on your experience, some technical suggestion, also at networking level, that I can follow?

Thanks again for your time.

Regards.

Massimo

Bart_Heungens
Honored Contributor

Re: Dual controller for dual VSA question

Hi,

I mentioned most already in my previous posts...Follow the best practices, and if you continue with 2 VSA's, know the limitations and weaknesses like the need for separating all controllers and network cards... For that follow the best practices as well on VMware side with vswitches and network balancing...

Kr,

Bart

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