Hi

When we create a snapshot image manually, we may use addsnapshot command.
This command provides us options; -prepare and -trigger.
Would you please tell me the details of these two options?
I would like to know purposes of these options. The use- case may be appreciated, also.
I think they are something to do with ISV internal cache management for snapshot operation.
(like prestartfcconsistgrp and startfcconsistgrp commands for Legacy FlashCopy)

Thank you, Eiichiro

Hello!

Have you already referenced the documentation for these commands? as per https://www.ibm.com/docs/en/flashsystem-9x00/8.7.0?topic=sc-addsnapshot-1

For most use cases I would recommend using the GUI to go through your required use cases first and use it to determine the common CLI workflows as those can be seen from the GUI execution modals.

I hope this is helpful!

Hi

When we create a snapshot image manually, we may use addsnapshot command.
This command provides us options; -prepare and -trigger.
Would you please tell me the details of these two options?
I would like to know purposes of these options. The use- case may be appreciated, also.
I think they are something to do with ISV internal cache management for snapshot operation.
(like prestartfcconsistgrp and startfcconsistgrp commands for Legacy FlashCopy)

Thank you, Eiichiro

Hi,
Yes, I had read through the command reference before posting this question.
Unfortunately, I could not understand the technical purpose of these two options.
What is the purpose to execute addsnapshot twice; addsnapshot -prepare, then, addsnapshot -trigger?
Unfortunately, my customer wants to manage snapshots with CLI scripting.
Thank you, Eiichiro

------------------------------
EIICHIROH NAKAGAWA

Original Message:
Sent: Mon January 27, 2025 05:32 AM
From: Evelyn Perez
Subject: ISV addsnapshot -prepare and -trigger

Hello!

Have you already referenced the documentation for these commands? as per https://www.ibm.com/docs/en/flashsystem-9x00/8.7.0?topic=sc-addsnapshot-1

For most use cases I would recommend using the GUI to go through your required use cases first and use it to determine the common CLI workflows as those can be seen from the GUI execution modals.

I hope this is helpful!

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

Original Message:
Sent: Thu January 23, 2025 01:50 AM
From: EIICHIROH NAKAGAWA
Subject: ISV addsnapshot -prepare and -trigger

Hi

When we create a snapshot image manually, we may use addsnapshot command.
This command provides us options; -prepare and -trigger.
Would you please tell me the details of these two options?
I would like to know purposes of these options. The use- case may be appreciated, also.
I think they are something to do with ISV internal cache management for snapshot operation.
(like prestartfcconsistgrp and startfcconsistgrp commands for Legacy FlashCopy)

Thank you, Eiichiro

------------------------------
EIICHIROH NAKAGAWA
------------------------------

Hello again,

addsnapshot will create the objects to hold point in time images of a volume or the set of volumes in a volume group.  The -prepare parameter will create but not populate the data for the point in time image.  The -trigger operation (which must specify a previously prepared snapshot) will populate the Point In Time image at which point the snapshot and vdisk will be mutually consistent.

If you don't specify prepare or trigger addsnapshot will perform both operations before completing.

Under what use cases should use the prepare/trigger ?

For large sets of volumes the creation and population of the point in time copy can take a long time to complete.  If Host IO is interrupted during the process you may want to break the operation in to two steps.  So the primary use case is for hosts that are very sensitive to pauses using very large numbers/capacity of volumes in a single volume group.

For most users, calling addsnapshot in one operation is preferred.  

I hope that clarifies things.

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

Original Message:
Sent: Tue January 28, 2025 01:16 AM
From: EIICHIROH NAKAGAWA
Subject: ISV addsnapshot -prepare and -trigger

Hi,
Yes, I had read through the command reference before posting this question.
Unfortunately, I could not understand the technical purpose of these two options.
What is the purpose to execute addsnapshot twice; addsnapshot -prepare, then, addsnapshot -trigger?
Unfortunately, my customer wants to manage snapshots with CLI scripting.
Thank you, Eiichiro

------------------------------
EIICHIROH NAKAGAWA

Original Message:
Sent: Mon January 27, 2025 05:32 AM
From: Evelyn Perez
Subject: ISV addsnapshot -prepare and -trigger

Hello!

Have you already referenced the documentation for these commands? as per https://www.ibm.com/docs/en/flashsystem-9x00/8.7.0?topic=sc-addsnapshot-1

For most use cases I would recommend using the GUI to go through your required use cases first and use it to determine the common CLI workflows as those can be seen from the GUI execution modals.

I hope this is helpful!

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

Original Message:
Sent: Thu January 23, 2025 01:50 AM
From: EIICHIROH NAKAGAWA
Subject: ISV addsnapshot -prepare and -trigger

Hi

When we create a snapshot image manually, we may use addsnapshot command.
This command provides us options; -prepare and -trigger.
Would you please tell me the details of these two options?
I would like to know purposes of these options. The use- case may be appreciated, also.
I think they are something to do with ISV internal cache management for snapshot operation.
(like prestartfcconsistgrp and startfcconsistgrp commands for Legacy FlashCopy)

Thank you, Eiichiro

------------------------------
EIICHIROH NAKAGAWA
------------------------------

Evelyn, I appreciate your kind explanation.

"If Host IO is interrupted during the process you may want to break the operation in to two steps. "
This case may happen on several users' environment.
It is my understanding that ISV put the cache into write-through mode on the source volumes after executing 'addsnapshot -prepare' until completing 'addsnapshot -trigger'
Is this correct?

"For most users, calling addsnapshot in one operation is preferred. "
I see, I will follow your suggestion as general solution.

Sincerely, Eiichiro

Hello again,

addsnapshot will create the objects to hold point in time images of a volume or the set of volumes in a volume group.  The -prepare parameter will create but not populate the data for the point in time image.  The -trigger operation (which must specify a previously prepared snapshot) will populate the Point In Time image at which point the snapshot and vdisk will be mutually consistent.

If you don't specify prepare or trigger addsnapshot will perform both operations before completing.

Under what use cases should use the prepare/trigger ?

For large sets of volumes the creation and population of the point in time copy can take a long time to complete.  If Host IO is interrupted during the process you may want to break the operation in to two steps.  So the primary use case is for hosts that are very sensitive to pauses using very large numbers/capacity of volumes in a single volume group.

For most users, calling addsnapshot in one operation is preferred.  

I hope that clarifies things.

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

Original Message:
Sent: Tue January 28, 2025 01:16 AM
From: EIICHIROH NAKAGAWA
Subject: ISV addsnapshot -prepare and -trigger

Hi,
Yes, I had read through the command reference before posting this question.
Unfortunately, I could not understand the technical purpose of these two options.
What is the purpose to execute addsnapshot twice; addsnapshot -prepare, then, addsnapshot -trigger?
Unfortunately, my customer wants to manage snapshots with CLI scripting.
Thank you, Eiichiro

------------------------------
EIICHIROH NAKAGAWA

Original Message:
Sent: Mon January 27, 2025 05:32 AM
From: Evelyn Perez
Subject: ISV addsnapshot -prepare and -trigger

Hello!

Have you already referenced the documentation for these commands? as per https://www.ibm.com/docs/en/flashsystem-9x00/8.7.0?topic=sc-addsnapshot-1

For most use cases I would recommend using the GUI to go through your required use cases first and use it to determine the common CLI workflows as those can be seen from the GUI execution modals.

I hope this is helpful!

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

Original Message:
Sent: Thu January 23, 2025 01:50 AM
From: EIICHIROH NAKAGAWA
Subject: ISV addsnapshot -prepare and -trigger

Hi

When we create a snapshot image manually, we may use addsnapshot command.
This command provides us options; -prepare and -trigger.
Would you please tell me the details of these two options?
I would like to know purposes of these options. The use- case may be appreciated, also.
I think they are something to do with ISV internal cache management for snapshot operation.
(like prestartfcconsistgrp and startfcconsistgrp commands for Legacy FlashCopy)

Thank you, Eiichiro

------------------------------
EIICHIROH NAKAGAWA
------------------------------

Hello!

I am not sure what you mean by ISV in this context.

Virtualize does not change the cache write of the product volumes when performing an addsnapshot -prepare.  The -prepare step does the complex object setup but doesn't touch the IO flow. 

Evelyn, I appreciate your kind explanation.

"If Host IO is interrupted during the process you may want to break the operation in to two steps. "
This case may happen on several users' environment.
It is my understanding that ISV put the cache into write-through mode on the source volumes after executing 'addsnapshot -prepare' until completing 'addsnapshot -trigger'
Is this correct?

"For most users, calling addsnapshot in one operation is preferred. "
I see, I will follow your suggestion as general solution.

Sincerely, Eiichiro

Hello again,

addsnapshot will create the objects to hold point in time images of a volume or the set of volumes in a volume group.  The -prepare parameter will create but not populate the data for the point in time image.  The -trigger operation (which must specify a previously prepared snapshot) will populate the Point In Time image at which point the snapshot and vdisk will be mutually consistent.

If you don't specify prepare or trigger addsnapshot will perform both operations before completing.

Under what use cases should use the prepare/trigger ?

For large sets of volumes the creation and population of the point in time copy can take a long time to complete.  If Host IO is interrupted during the process you may want to break the operation in to two steps.  So the primary use case is for hosts that are very sensitive to pauses using very large numbers/capacity of volumes in a single volume group.

For most users, calling addsnapshot in one operation is preferred.  

I hope that clarifies things.

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

Original Message:
Sent: Tue January 28, 2025 01:16 AM
From: EIICHIROH NAKAGAWA
Subject: ISV addsnapshot -prepare and -trigger

Hi,
Yes, I had read through the command reference before posting this question.
Unfortunately, I could not understand the technical purpose of these two options.
What is the purpose to execute addsnapshot twice; addsnapshot -prepare, then, addsnapshot -trigger?
Unfortunately, my customer wants to manage snapshots with CLI scripting.
Thank you, Eiichiro

------------------------------
EIICHIROH NAKAGAWA

Original Message:
Sent: Mon January 27, 2025 05:32 AM
From: Evelyn Perez
Subject: ISV addsnapshot -prepare and -trigger

Hello!

Have you already referenced the documentation for these commands? as per https://www.ibm.com/docs/en/flashsystem-9x00/8.7.0?topic=sc-addsnapshot-1

For most use cases I would recommend using the GUI to go through your required use cases first and use it to determine the common CLI workflows as those can be seen from the GUI execution modals.

I hope this is helpful!

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

Original Message:
Sent: Thu January 23, 2025 01:50 AM
From: EIICHIROH NAKAGAWA
Subject: ISV addsnapshot -prepare and -trigger

Hi

When we create a snapshot image manually, we may use addsnapshot command.
This command provides us options; -prepare and -trigger.
Would you please tell me the details of these two options?
I would like to know purposes of these options. The use- case may be appreciated, also.
I think they are something to do with ISV internal cache management for snapshot operation.
(like prestartfcconsistgrp and startfcconsistgrp commands for Legacy FlashCopy)

Thank you, Eiichiro

------------------------------
EIICHIROH NAKAGAWA
------------------------------

Hi Evelyn

I might misunderstand the addsnapshot -prepare.
I thought it was something like prestartfcconsistgrp.
A prestartfcconsistgrp flushes the cache of any data that is destined for the source volume and forces the cache into the write-through mode until performing startfcconsistgrp.
So, I thought an addsnapshot -prepare performs the same manner.
i.e.
"addsnapshot -prepare"  performs like "prestartfcconsistgrp"
"addsnapshot -trigger"  performs like "startfcconsistgrp"

Again, I appreciate your explanation.

Sincerely, Eiichiro

p.s. I mean ISV as IBM Storage Virtualize.

Hello!

I am not sure what you mean by ISV in this context.

Virtualize does not change the cache write of the product volumes when performing an addsnapshot -prepare.  The -prepare step does the complex object setup but doesn't touch the IO flow. 

Evelyn, I appreciate your kind explanation.

"If Host IO is interrupted during the process you may want to break the operation in to two steps. "
This case may happen on several users' environment.
It is my understanding that ISV put the cache into write-through mode on the source volumes after executing 'addsnapshot -prepare' until completing 'addsnapshot -trigger'
Is this correct?

"For most users, calling addsnapshot in one operation is preferred. "
I see, I will follow your suggestion as general solution.

Sincerely, Eiichiro

Hello again,

addsnapshot will create the objects to hold point in time images of a volume or the set of volumes in a volume group.  The -prepare parameter will create but not populate the data for the point in time image.  The -trigger operation (which must specify a previously prepared snapshot) will populate the Point In Time image at which point the snapshot and vdisk will be mutually consistent.

If you don't specify prepare or trigger addsnapshot will perform both operations before completing.

Under what use cases should use the prepare/trigger ?

For large sets of volumes the creation and population of the point in time copy can take a long time to complete.  If Host IO is interrupted during the process you may want to break the operation in to two steps.  So the primary use case is for hosts that are very sensitive to pauses using very large numbers/capacity of volumes in a single volume group.

For most users, calling addsnapshot in one operation is preferred.  

I hope that clarifies things.

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

Original Message:
Sent: Tue January 28, 2025 01:16 AM
From: EIICHIROH NAKAGAWA
Subject: ISV addsnapshot -prepare and -trigger

Hi,
Yes, I had read through the command reference before posting this question.
Unfortunately, I could not understand the technical purpose of these two options.
What is the purpose to execute addsnapshot twice; addsnapshot -prepare, then, addsnapshot -trigger?
Unfortunately, my customer wants to manage snapshots with CLI scripting.
Thank you, Eiichiro

------------------------------
EIICHIROH NAKAGAWA

Original Message:
Sent: Mon January 27, 2025 05:32 AM
From: Evelyn Perez
Subject: ISV addsnapshot -prepare and -trigger

Hello!

Have you already referenced the documentation for these commands? as per https://www.ibm.com/docs/en/flashsystem-9x00/8.7.0?topic=sc-addsnapshot-1

For most use cases I would recommend using the GUI to go through your required use cases first and use it to determine the common CLI workflows as those can be seen from the GUI execution modals.

I hope this is helpful!

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

Original Message:
Sent: Thu January 23, 2025 01:50 AM
From: EIICHIROH NAKAGAWA
Subject: ISV addsnapshot -prepare and -trigger

Hi

When we create a snapshot image manually, we may use addsnapshot command.
This command provides us options; -prepare and -trigger.
Would you please tell me the details of these two options?
I would like to know purposes of these options. The use- case may be appreciated, also.
I think they are something to do with ISV internal cache management for snapshot operation.
(like prestartfcconsistgrp and startfcconsistgrp commands for Legacy FlashCopy)

Thank you, Eiichiro

------------------------------
EIICHIROH NAKAGAWA
------------------------------

Hello,

The internals are quite a bit different compared to flashcopy, as it is intended to be simpler and require less detailed understanding.  Prepare is just creating all the objects and associations.  It does not change or alter the IO Path.  Trigger will start the copying.

I hope this helps,

Hi Evelyn

I might misunderstand the addsnapshot -prepare.
I thought it was something like prestartfcconsistgrp.
A prestartfcconsistgrp flushes the cache of any data that is destined for the source volume and forces the cache into the write-through mode until performing startfcconsistgrp.
So, I thought an addsnapshot -prepare performs the same manner.
i.e.
"addsnapshot -prepare"  performs like "prestartfcconsistgrp"
"addsnapshot -trigger"  performs like "startfcconsistgrp"

Again, I appreciate your explanation.

Sincerely, Eiichiro

p.s. I mean ISV as IBM Storage Virtualize.

Hello!

I am not sure what you mean by ISV in this context.

Virtualize does not change the cache write of the product volumes when performing an addsnapshot -prepare.  The -prepare step does the complex object setup but doesn't touch the IO flow. 

Evelyn, I appreciate your kind explanation.

"If Host IO is interrupted during the process you may want to break the operation in to two steps. "
This case may happen on several users' environment.
It is my understanding that ISV put the cache into write-through mode on the source volumes after executing 'addsnapshot -prepare' until completing 'addsnapshot -trigger'
Is this correct?

"For most users, calling addsnapshot in one operation is preferred. "
I see, I will follow your suggestion as general solution.

Sincerely, Eiichiro

Hello again,

addsnapshot will create the objects to hold point in time images of a volume or the set of volumes in a volume group.  The -prepare parameter will create but not populate the data for the point in time image.  The -trigger operation (which must specify a previously prepared snapshot) will populate the Point In Time image at which point the snapshot and vdisk will be mutually consistent.

If you don't specify prepare or trigger addsnapshot will perform both operations before completing.

Under what use cases should use the prepare/trigger ?

For large sets of volumes the creation and population of the point in time copy can take a long time to complete.  If Host IO is interrupted during the process you may want to break the operation in to two steps.  So the primary use case is for hosts that are very sensitive to pauses using very large numbers/capacity of volumes in a single volume group.

For most users, calling addsnapshot in one operation is preferred.  

I hope that clarifies things.

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

Original Message:
Sent: Tue January 28, 2025 01:16 AM
From: EIICHIROH NAKAGAWA
Subject: ISV addsnapshot -prepare and -trigger

Hi,
Yes, I had read through the command reference before posting this question.
Unfortunately, I could not understand the technical purpose of these two options.
What is the purpose to execute addsnapshot twice; addsnapshot -prepare, then, addsnapshot -trigger?
Unfortunately, my customer wants to manage snapshots with CLI scripting.
Thank you, Eiichiro

------------------------------
EIICHIROH NAKAGAWA

Original Message:
Sent: Mon January 27, 2025 05:32 AM
From: Evelyn Perez
Subject: ISV addsnapshot -prepare and -trigger

Hello!

Have you already referenced the documentation for these commands? as per https://www.ibm.com/docs/en/flashsystem-9x00/8.7.0?topic=sc-addsnapshot-1

For most use cases I would recommend using the GUI to go through your required use cases first and use it to determine the common CLI workflows as those can be seen from the GUI execution modals.

I hope this is helpful!

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

Original Message:
Sent: Thu January 23, 2025 01:50 AM
From: EIICHIROH NAKAGAWA
Subject: ISV addsnapshot -prepare and -trigger

Hi

When we create a snapshot image manually, we may use addsnapshot command.
This command provides us options; -prepare and -trigger.
Would you please tell me the details of these two options?
I would like to know purposes of these options. The use- case may be appreciated, also.
I think they are something to do with ISV internal cache management for snapshot operation.
(like prestartfcconsistgrp and startfcconsistgrp commands for Legacy FlashCopy)

Thank you, Eiichiro

------------------------------
EIICHIROH NAKAGAWA
------------------------------