Primary Storage

I plan to expand an array size by adding two FCMs on a production system.
The current DRAID6 array consists of 13 19.2TB FCMs.

I have no plan to stop the attached servers for this expansion work.

I have two questions:

Q1:
The expandarray command usage says the following:
"Expansion can have an impact on host performance and latency when performed on an array that has over 50% load."

Would you please tell me what does "50% load" mean?
I need to know the exact metrics so that I can check the "50% load" on the FS7300
https://www.ibm.com/docs/en/flashsystem-7x00/8.5.x?topic=ac-expandarray

Q2:
How long does it take to complete the array expansion process after executing expandarray?  Are there any good estimation method?

Best regards, Eiichiro

Hello Nakagawa-san,

Q1 is a valid question, which I cannot offer an answer for as of now.
To know 50%, we'd need to know what the 100% load would be, I will consult on that with the community.
Perhaps, someone else can contribute some useful insight on that in the meantime.

For Q2: it is hard to estimate, if not even impossible. Since the array expansion process is a background task with low priority, the duration may vary during the process depending on the array's workload.
Once kicked off, lsarrayexpansionprogress provides an ETA.

I plan to expand an array size by adding two FCMs on a production system.
The current DRAID6 array consists of 13 19.2TB FCMs.

I have no plan to stop the attached servers for this expansion work.

I have two questions:

Q1:
The expandarray command usage says the following:
"Expansion can have an impact on host performance and latency when performed on an array that has over 50% load."

Would you please tell me what does "50% load" mean?
I need to know the exact metrics so that I can check the "50% load" on the FS7300
https://www.ibm.com/docs/en/flashsystem-7x00/8.5.x?topic=ac-expandarray

Q2:
How long does it take to complete the array expansion process after executing expandarray?  Are there any good estimation method?

Best regards, Eiichiro

Hello Nakagawa-san,

Q1 is a valid question, which I cannot offer an answer for as of now.
To know 50%, we'd need to know what the 100% load would be, I will consult on that with the community.
Perhaps, someone else can contribute some useful insight on that in the meantime.

For Q2: it is hard to estimate, if not even impossible. Since the array expansion process is a background task with low priority, the duration may vary during the process depending on the array's workload.
Once kicked off, lsarrayexpansionprogress provides an ETA.

I plan to expand an array size by adding two FCMs on a production system.
The current DRAID6 array consists of 13 19.2TB FCMs.

I have no plan to stop the attached servers for this expansion work.

I have two questions:

Q1:
The expandarray command usage says the following:
"Expansion can have an impact on host performance and latency when performed on an array that has over 50% load."

Would you please tell me what does "50% load" mean?
I need to know the exact metrics so that I can check the "50% load" on the FS7300
https://www.ibm.com/docs/en/flashsystem-7x00/8.5.x?topic=ac-expandarray

Q2:
How long does it take to complete the array expansion process after executing expandarray?  Are there any good estimation method?

Best regards, Eiichiro

I plan to expand an array size by adding two FCMs on a production system.
The current DRAID6 array consists of 13 19.2TB FCMs.

I have no plan to stop the attached servers for this expansion work.

I have two questions:

Q1:
The expandarray command usage says the following:
"Expansion can have an impact on host performance and latency when performed on an array that has over 50% load."

Would you please tell me what does "50% load" mean?
I need to know the exact metrics so that I can check the "50% load" on the FS7300
https://www.ibm.com/docs/en/flashsystem-7x00/8.5.x?topic=ac-expandarray

Q2:
How long does it take to complete the array expansion process after executing expandarray?  Are there any good estimation method?

Best regards, Eiichiro

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

I plan to expand an array size by adding two FCMs on a production system.
The current DRAID6 array consists of 13 19.2TB FCMs.

I have no plan to stop the attached servers for this expansion work.

I have two questions:

Q1:
The expandarray command usage says the following:
"Expansion can have an impact on host performance and latency when performed on an array that has over 50% load."

Would you please tell me what does "50% load" mean?
I need to know the exact metrics so that I can check the "50% load" on the FS7300
https://www.ibm.com/docs/en/flashsystem-7x00/8.5.x?topic=ac-expandarray

Q2:
How long does it take to complete the array expansion process after executing expandarray?  Are there any good estimation method?

Best regards, Eiichiro