Hi,

We have the following config on one of our customers and are a little confused as how the SVC is reporting Usable Capacity at a pool level compared to the backend FCM storage arrays. Is the reason why the usable capacity numbers are different due to the different code levels between SVC and storage arrays?:

SVC - 8.3.1.3 software level

• Two FS7200 storage pools, each reporting approx 342TiB used capacity out of 548TiB of total usable capacity (they are mirrors of each other through vdisk copies, hence the same usage) - This is working as expected
• Two FS7300 Storage pools, each reporting approx 278TiB used capacity out of 548TiB of total usable capacity - This is reporting incorrectly

2 x FS7200 - 8.3.1.5

• Single FCM pool per array, reporting 342TiB used capacity out of 548TiB total - matches SVC

2 x FS7300 - 8.5.0.5 - Newly installed a couple of months ago

• Single FCM pool per array, reporting 178TiB used capacity out of 548TiB total - does not match SVC, is 100TiB less!

So as you can see, the SVC for some reason is adding approx 100TiB to it's used capacity compared to the backend storage. Are we right to assume the backend storage is correct, and when we get the SVC and FS7x00's upgraded to latest levels later this year, the SVC will report the used capacity correctly as per the backend FS7300's? And the reason for the discrepancy is that the SVC is back level to the FS7300 and can't correctly obtain the actual usage?

It does make it a little tricky to get the total usage stats for the customer, but as long as we know tro trust the backend rather than SVC stats, we can come up with the right total.

Thanks, Andy

Hi,

We have the following config on one of our customers and are a little confused as how the SVC is reporting Usable Capacity at a pool level compared to the backend FCM storage arrays. Is the reason why the usable capacity numbers are different due to the different code levels between SVC and storage arrays?:

SVC - 8.3.1.3 software level

• Two FS7200 storage pools, each reporting approx 342TiB used capacity out of 548TiB of total usable capacity (they are mirrors of each other through vdisk copies, hence the same usage) - This is working as expected
• Two FS7300 Storage pools, each reporting approx 278TiB used capacity out of 548TiB of total usable capacity - This is reporting incorrectly

2 x FS7200 - 8.3.1.5

• Single FCM pool per array, reporting 342TiB used capacity out of 548TiB total - matches SVC

2 x FS7300 - 8.5.0.5 - Newly installed a couple of months ago

• Single FCM pool per array, reporting 178TiB used capacity out of 548TiB total - does not match SVC, is 100TiB less!

So as you can see, the SVC for some reason is adding approx 100TiB to it's used capacity compared to the backend storage. Are we right to assume the backend storage is correct, and when we get the SVC and FS7x00's upgraded to latest levels later this year, the SVC will report the used capacity correctly as per the backend FS7300's? And the reason for the discrepancy is that the SVC is back level to the FS7300 and can't correctly obtain the actual usage?

It does make it a little tricky to get the total usage stats for the customer, but as long as we know tro trust the backend rather than SVC stats, we can come up with the right total.

Thanks, Andy

One thing to check regarding capacity numbers is to compare the scsi unmap settings  (lssystem | grep unmap).

Maybe unmap is turned off on the FS7300.

Hi,

We have the following config on one of our customers and are a little confused as how the SVC is reporting Usable Capacity at a pool level compared to the backend FCM storage arrays. Is the reason why the usable capacity numbers are different due to the different code levels between SVC and storage arrays?:

SVC - 8.3.1.3 software level

• Two FS7200 storage pools, each reporting approx 342TiB used capacity out of 548TiB of total usable capacity (they are mirrors of each other through vdisk copies, hence the same usage) - This is working as expected
• Two FS7300 Storage pools, each reporting approx 278TiB used capacity out of 548TiB of total usable capacity - This is reporting incorrectly

2 x FS7200 - 8.3.1.5

• Single FCM pool per array, reporting 342TiB used capacity out of 548TiB total - matches SVC

2 x FS7300 - 8.5.0.5 - Newly installed a couple of months ago

• Single FCM pool per array, reporting 178TiB used capacity out of 548TiB total - does not match SVC, is 100TiB less!

So as you can see, the SVC for some reason is adding approx 100TiB to it's used capacity compared to the backend storage. Are we right to assume the backend storage is correct, and when we get the SVC and FS7x00's upgraded to latest levels later this year, the SVC will report the used capacity correctly as per the backend FS7300's? And the reason for the discrepancy is that the SVC is back level to the FS7300 and can't correctly obtain the actual usage?

It does make it a little tricky to get the total usage stats for the customer, but as long as we know tro trust the backend rather than SVC stats, we can come up with the right total.

Thanks, Andy

Hi Hans, 

You were 100% correct, we'd forgotten to change the scsi unmap settings on the SVC for the new FS7300 storage arrays! I changed them on Friday, came back in to work on Monday and hey presto, the SVC was reporting the correct usage on the storage pools matching the backend FS7300 :-)

Thanks very much for the help,

Andy

------------------------------
Andy 91717

Original Message:
Sent: Thu June 15, 2023 08:42 AM
From: Hans Populaire
Subject: SVC Usable Capacity - Code level related?

One thing to check regarding capacity numbers is to compare the scsi unmap settings  (lssystem | grep unmap).

Maybe unmap is turned off on the FS7300.

------------------------------
Hans Populaire

Original Message:
Sent: Tue June 13, 2023 08:47 AM
From: Andy 91717
Subject: SVC Usable Capacity - Code level related?

Hi,

We have the following config on one of our customers and are a little confused as how the SVC is reporting Usable Capacity at a pool level compared to the backend FCM storage arrays. Is the reason why the usable capacity numbers are different due to the different code levels between SVC and storage arrays?:

SVC - 8.3.1.3 software level

• Two FS7200 storage pools, each reporting approx 342TiB used capacity out of 548TiB of total usable capacity (they are mirrors of each other through vdisk copies, hence the same usage) - This is working as expected
• Two FS7300 Storage pools, each reporting approx 278TiB used capacity out of 548TiB of total usable capacity - This is reporting incorrectly

2 x FS7200 - 8.3.1.5

• Single FCM pool per array, reporting 342TiB used capacity out of 548TiB total - matches SVC

2 x FS7300 - 8.5.0.5 - Newly installed a couple of months ago

• Single FCM pool per array, reporting 178TiB used capacity out of 548TiB total - does not match SVC, is 100TiB less!

So as you can see, the SVC for some reason is adding approx 100TiB to it's used capacity compared to the backend storage. Are we right to assume the backend storage is correct, and when we get the SVC and FS7x00's upgraded to latest levels later this year, the SVC will report the used capacity correctly as per the backend FS7300's? And the reason for the discrepancy is that the SVC is back level to the FS7300 and can't correctly obtain the actual usage?

It does make it a little tricky to get the total usage stats for the customer, but as long as we know tro trust the backend rather than SVC stats, we can come up with the right total.

Thanks, Andy

------------------------------
Andy 91717
------------------------------

Hiya - did you use the 7300 wizard to configure this backend storage?  Because that should have enabled it... It also does a lot of best practices in terms of presented volumes.

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

Original Message:
Sent: Tue June 20, 2023 05:38 AM
From: Andy 91717
Subject: SVC Usable Capacity - Code level related?

Hi Hans, 

You were 100% correct, we'd forgotten to change the scsi unmap settings on the SVC for the new FS7300 storage arrays! I changed them on Friday, came back in to work on Monday and hey presto, the SVC was reporting the correct usage on the storage pools matching the backend FS7300 :-)

Thanks very much for the help,

Andy

------------------------------
Andy 91717

Original Message:
Sent: Thu June 15, 2023 08:42 AM
From: Hans Populaire
Subject: SVC Usable Capacity - Code level related?

One thing to check regarding capacity numbers is to compare the scsi unmap settings  (lssystem | grep unmap).

Maybe unmap is turned off on the FS7300.

------------------------------
Hans Populaire

Original Message:
Sent: Tue June 13, 2023 08:47 AM
From: Andy 91717
Subject: SVC Usable Capacity - Code level related?

Hi,

We have the following config on one of our customers and are a little confused as how the SVC is reporting Usable Capacity at a pool level compared to the backend FCM storage arrays. Is the reason why the usable capacity numbers are different due to the different code levels between SVC and storage arrays?:

SVC - 8.3.1.3 software level

• Two FS7200 storage pools, each reporting approx 342TiB used capacity out of 548TiB of total usable capacity (they are mirrors of each other through vdisk copies, hence the same usage) - This is working as expected
• Two FS7300 Storage pools, each reporting approx 278TiB used capacity out of 548TiB of total usable capacity - This is reporting incorrectly

2 x FS7200 - 8.3.1.5

• Single FCM pool per array, reporting 342TiB used capacity out of 548TiB total - matches SVC

2 x FS7300 - 8.5.0.5 - Newly installed a couple of months ago

• Single FCM pool per array, reporting 178TiB used capacity out of 548TiB total - does not match SVC, is 100TiB less!

So as you can see, the SVC for some reason is adding approx 100TiB to it's used capacity compared to the backend storage. Are we right to assume the backend storage is correct, and when we get the SVC and FS7x00's upgraded to latest levels later this year, the SVC will report the used capacity correctly as per the backend FS7300's? And the reason for the discrepancy is that the SVC is back level to the FS7300 and can't correctly obtain the actual usage?

It does make it a little tricky to get the total usage stats for the customer, but as long as we know tro trust the backend rather than SVC stats, we can come up with the right total.

Thanks, Andy

------------------------------
Andy 91717
------------------------------