Primary Storage

Hi Team,

please help me understanding the difference between Policy Based HA and Hyperswap

As of today we are running Hyperwap beween two Flashsystems. Both Systems serve preferred path IOs and providing non-preferred path IOs in case the preferred path is gone. Access to the Volume is given through both Systems the same time. Some primary volumes reside on site a and some on site b.

Will this be the same situation with Policy Based HA and all the pathes can be used or only in case of a failover?

Within Hyperswap a volume resides on a primary site which can be choosen during creation of the volume. This is important as write IOs will be handeld throuth the primary site.

Will this be the same situation on Policy based HA ?

If yes will the "primary" Pool then be coresponding to the primary site?

thanks 

------------------------------
Sebbo
------------------------------

Hi Team,

please help me understanding the difference between Policy Based HA and Hyperswap

As of today we are running Hyperwap beween two Flashsystems. Both Systems serve preferred path IOs and providing non-preferred path IOs in case the preferred path is gone. Access to the Volume is given through both Systems the same time. Some primary volumes reside on site a and some on site b.

Will this be the same situation with Policy Based HA and all the pathes can be used or only in case of a failover?

Within Hyperswap a volume resides on a primary site which can be choosen during creation of the volume. This is important as write IOs will be handeld throuth the primary site.

Will this be the same situation on Policy based HA ?

If yes will the "primary" Pool then be coresponding to the primary site?

thanks 

------------------------------
Sebbo
------------------------------

Hi Sebbo, to add to Nezih's excellent post:

PBHA is the replacement technology for Hyperswap and differs in many ways from an implementation and a few key ways from a deployment perspective:

Hyperswap is set up within a single system and was limited by our existing Remote copy architecture, meaning it had performance, volume and Bandwidth limits of that code architecture.  The Single System is one slightly nice in that you are only dealing with one cluster for things like upgrade, but has the disadvantage that you are still sharing the same cluster state machine across all node, so a code failure there impacts the system.  It also means that for any local volumes (e.g. not replicated) a problem with the link could mean that you lose local access as the entire cluster has to see volumes for them to be active.

PBHA is between two independent systems and has more robustness in that you can have local and remote partitions set up on the system machine.  Loss of access to the replication partner only results in access to the remote partitions on one site.  You will have to upgrade the systems separately, however, advances in our management interfaces means you only have to do the initial configuration of the partnership and then all objects in that partition are only managed/created/changed on one site so it gives you the advantage of a single system management within a partition, but the high availability of two distinct systems.

there are also very large performance deltas as the new PBHA is using our new replication technology that scales a lot closer to non replicated traffic.  I recommend trying it out as Nezih recommends or trialling a proof of concept.  I think you will find the management much easier along with the other (performance) benefits PBHA offers.

Hi Team,

please help me understanding the difference between Policy Based HA and Hyperswap

As of today we are running Hyperwap beween two Flashsystems. Both Systems serve preferred path IOs and providing non-preferred path IOs in case the preferred path is gone. Access to the Volume is given through both Systems the same time. Some primary volumes reside on site a and some on site b.

Will this be the same situation with Policy Based HA and all the pathes can be used or only in case of a failover?

Within Hyperswap a volume resides on a primary site which can be choosen during creation of the volume. This is important as write IOs will be handeld throuth the primary site.

Will this be the same situation on Policy based HA ?

If yes will the "primary" Pool then be coresponding to the primary site?

thanks 

------------------------------
Sebbo
------------------------------

Hi Sebbo, to add to Nezih's excellent post:

PBHA is the replacement technology for Hyperswap and differs in many ways from an implementation and a few key ways from a deployment perspective:

Hyperswap is set up within a single system and was limited by our existing Remote copy architecture, meaning it had performance, volume and Bandwidth limits of that code architecture.  The Single System is one slightly nice in that you are only dealing with one cluster for things like upgrade, but has the disadvantage that you are still sharing the same cluster state machine across all node, so a code failure there impacts the system.  It also means that for any local volumes (e.g. not replicated) a problem with the link could mean that you lose local access as the entire cluster has to see volumes for them to be active.

PBHA is between two independent systems and has more robustness in that you can have local and remote partitions set up on the system machine.  Loss of access to the replication partner only results in access to the remote partitions on one site.  You will have to upgrade the systems separately, however, advances in our management interfaces means you only have to do the initial configuration of the partnership and then all objects in that partition are only managed/created/changed on one site so it gives you the advantage of a single system management within a partition, but the high availability of two distinct systems.

there are also very large performance deltas as the new PBHA is using our new replication technology that scales a lot closer to non replicated traffic.  I recommend trying it out as Nezih recommends or trialling a proof of concept.  I think you will find the management much easier along with the other (performance) benefits PBHA offers.

------------------------------
Evelyn Perez
IBM Senior Technical Staff Member
IBM Storage Virtualize Software Architect for SVC and FlashSystem

Original Message:
Sent: Fri February 02, 2024 05:48 AM
From: Sebbo
Subject: HyperSwap vs Policy Based HA whats the diffference

Hi Team,

please help me understanding the difference between Policy Based HA and Hyperswap

As of today we are running Hyperwap beween two Flashsystems. Both Systems serve preferred path IOs and providing non-preferred path IOs in case the preferred path is gone. Access to the Volume is given through both Systems the same time. Some primary volumes reside on site a and some on site b.

Will this be the same situation with Policy Based HA and all the pathes can be used or only in case of a failover?

Within Hyperswap a volume resides on a primary site which can be choosen during creation of the volume. This is important as write IOs will be handeld throuth the primary site.

Will this be the same situation on Policy based HA ?

If yes will the "primary" Pool then be coresponding to the primary site?

thanks 

------------------------------
Sebbo
------------------------------

Hi Evelyn,

thank you for your focussed brief information. Am I right with the following advantage of PBHA?

Thinking of the 8-node-limitation for clusters, PBHA seems to use a different way, that allows to migrate from or even between two 8-node-clusters.

Hi Sebbo, to add to Nezih's excellent post:

PBHA is the replacement technology for Hyperswap and differs in many ways from an implementation and a few key ways from a deployment perspective:

Hyperswap is set up within a single system and was limited by our existing Remote copy architecture, meaning it had performance, volume and Bandwidth limits of that code architecture.  The Single System is one slightly nice in that you are only dealing with one cluster for things like upgrade, but has the disadvantage that you are still sharing the same cluster state machine across all node, so a code failure there impacts the system.  It also means that for any local volumes (e.g. not replicated) a problem with the link could mean that you lose local access as the entire cluster has to see volumes for them to be active.

PBHA is between two independent systems and has more robustness in that you can have local and remote partitions set up on the system machine.  Loss of access to the replication partner only results in access to the remote partitions on one site.  You will have to upgrade the systems separately, however, advances in our management interfaces means you only have to do the initial configuration of the partnership and then all objects in that partition are only managed/created/changed on one site so it gives you the advantage of a single system management within a partition, but the high availability of two distinct systems.

there are also very large performance deltas as the new PBHA is using our new replication technology that scales a lot closer to non replicated traffic.  I recommend trying it out as Nezih recommends or trialling a proof of concept.  I think you will find the management much easier along with the other (performance) benefits PBHA offers.

------------------------------
Evelyn Perez
IBM Senior Technical Staff Member
IBM Storage Virtualize Software Architect for SVC and FlashSystem

Original Message:
Sent: Fri February 02, 2024 05:48 AM
From: Sebbo
Subject: HyperSwap vs Policy Based HA whats the diffference

Hi Team,

please help me understanding the difference between Policy Based HA and Hyperswap

As of today we are running Hyperwap beween two Flashsystems. Both Systems serve preferred path IOs and providing non-preferred path IOs in case the preferred path is gone. Access to the Volume is given through both Systems the same time. Some primary volumes reside on site a and some on site b.

Will this be the same situation with Policy Based HA and all the pathes can be used or only in case of a failover?

Within Hyperswap a volume resides on a primary site which can be choosen during creation of the volume. This is important as write IOs will be handeld throuth the primary site.

Will this be the same situation on Policy based HA ?

If yes will the "primary" Pool then be coresponding to the primary site?

thanks 

------------------------------
Sebbo
------------------------------

Hi Sebbo, to add to Nezih's excellent post:

PBHA is the replacement technology for Hyperswap and differs in many ways from an implementation and a few key ways from a deployment perspective:

Hyperswap is set up within a single system and was limited by our existing Remote copy architecture, meaning it had performance, volume and Bandwidth limits of that code architecture.  The Single System is one slightly nice in that you are only dealing with one cluster for things like upgrade, but has the disadvantage that you are still sharing the same cluster state machine across all node, so a code failure there impacts the system.  It also means that for any local volumes (e.g. not replicated) a problem with the link could mean that you lose local access as the entire cluster has to see volumes for them to be active.

PBHA is between two independent systems and has more robustness in that you can have local and remote partitions set up on the system machine.  Loss of access to the replication partner only results in access to the remote partitions on one site.  You will have to upgrade the systems separately, however, advances in our management interfaces means you only have to do the initial configuration of the partnership and then all objects in that partition are only managed/created/changed on one site so it gives you the advantage of a single system management within a partition, but the high availability of two distinct systems.

there are also very large performance deltas as the new PBHA is using our new replication technology that scales a lot closer to non replicated traffic.  I recommend trying it out as Nezih recommends or trialling a proof of concept.  I think you will find the management much easier along with the other (performance) benefits PBHA offers.

------------------------------
Evelyn Perez
IBM Senior Technical Staff Member
IBM Storage Virtualize Software Architect for SVC and FlashSystem

Original Message:
Sent: Fri February 02, 2024 05:48 AM
From: Sebbo
Subject: HyperSwap vs Policy Based HA whats the diffference

Hi Team,

please help me understanding the difference between Policy Based HA and Hyperswap

As of today we are running Hyperwap beween two Flashsystems. Both Systems serve preferred path IOs and providing non-preferred path IOs in case the preferred path is gone. Access to the Volume is given through both Systems the same time. Some primary volumes reside on site a and some on site b.

Will this be the same situation with Policy Based HA and all the pathes can be used or only in case of a failover?

Within Hyperswap a volume resides on a primary site which can be choosen during creation of the volume. This is important as write IOs will be handeld throuth the primary site.

Will this be the same situation on Policy based HA ?

If yes will the "primary" Pool then be coresponding to the primary site?

thanks 

------------------------------
Sebbo
------------------------------

Edit: I got a pleasant response in another thread clarifying the question below - Host location settings would apply (multi)path definitions, hence "local" (near to host) copy of the HA volume will be used for R/W. Isn't it pretty much like SVC ESC would work?

------

Hi Evelyn! Not trying to hijack Sebbo's thread, but more in the way to add to the discussion, if you won`t mind clarify:

Consider a ISL attached PBHA scenario where a single VMware vSphere cluster "stretches" between locations, hence hosts from both sites are/must be added to a single storage partition, so all hosts within that cluster can access the same volumes; Hosts are split 50/50 between locations and sized so half cluster can handle 100% VM workload.

As stated PBHA hosts/volumes(groups) have their "preferred system" (or site) handled by policy at the storage partition level; If I got it correctly, in the said cluster setup half of the cluster will always access volumes cross-ISL for both reads and writes, is that right? Or there's granular host/volume affinity that could be setup within the storage partition? 

Thanks.

------------------------------
Thiago Lucas

Original Message:
Sent: Mon February 05, 2024 12:19 PM
From: Evelyn Perez
Subject: HyperSwap vs Policy Based HA whats the diffference

Hi Sebbo, to add to Nezih's excellent post:

PBHA is the replacement technology for Hyperswap and differs in many ways from an implementation and a few key ways from a deployment perspective:

Hyperswap is set up within a single system and was limited by our existing Remote copy architecture, meaning it had performance, volume and Bandwidth limits of that code architecture.  The Single System is one slightly nice in that you are only dealing with one cluster for things like upgrade, but has the disadvantage that you are still sharing the same cluster state machine across all node, so a code failure there impacts the system.  It also means that for any local volumes (e.g. not replicated) a problem with the link could mean that you lose local access as the entire cluster has to see volumes for them to be active.

PBHA is between two independent systems and has more robustness in that you can have local and remote partitions set up on the system machine.  Loss of access to the replication partner only results in access to the remote partitions on one site.  You will have to upgrade the systems separately, however, advances in our management interfaces means you only have to do the initial configuration of the partnership and then all objects in that partition are only managed/created/changed on one site so it gives you the advantage of a single system management within a partition, but the high availability of two distinct systems.

there are also very large performance deltas as the new PBHA is using our new replication technology that scales a lot closer to non replicated traffic.  I recommend trying it out as Nezih recommends or trialling a proof of concept.  I think you will find the management much easier along with the other (performance) benefits PBHA offers.

------------------------------
Evelyn Perez
IBM Senior Technical Staff Member
IBM Storage Virtualize Software Architect for SVC and FlashSystem

Original Message:
Sent: Fri February 02, 2024 05:48 AM
From: Sebbo
Subject: HyperSwap vs Policy Based HA whats the diffference

Hi Team,

please help me understanding the difference between Policy Based HA and Hyperswap

As of today we are running Hyperwap beween two Flashsystems. Both Systems serve preferred path IOs and providing non-preferred path IOs in case the preferred path is gone. Access to the Volume is given through both Systems the same time. Some primary volumes reside on site a and some on site b.

Will this be the same situation with Policy Based HA and all the pathes can be used or only in case of a failover?

Within Hyperswap a volume resides on a primary site which can be choosen during creation of the volume. This is important as write IOs will be handeld throuth the primary site.

Will this be the same situation on Policy based HA ?

If yes will the "primary" Pool then be coresponding to the primary site?

thanks 

------------------------------
Sebbo
------------------------------