Write Back Status: Disabled

[gwijnants]

Hi all,

We have 2 MSA2060 with the same configuration.

1 diskgroup with 1 pool. I see that the Write Back Status is disabled for controller A. I have searched online for some help why it is disabled. The best thing I can find is to reboot the controller, but after reboot and even firmware update on both of our MSA2060 the Status stays disabled.

Is it because our virtual pool space high threshold has been exceeded? A configuration issue? I can't believe that both MSA2060 have the same hardware issue.

Below some info.

Best Regards,

Guy

# show disk-groups
Name Size Free Pool Tier % of Pool Own RAID Disks Chk Status Current Job Job% Sec Fmt Health
---------------------------------------------------------------------------------------------------------------------------
dgA01 19.1TB 94.4GB A Standard 100 A RAID6 10 512k FTOL VRSC 0% 512e OK
---------------------------------------------------------------------------------------------------------------------------
Success: Command completed successfully. (2023-10-25 15:06:31)
# show pools
Name Serial Number Blocksize Total Size Avail Snap Size OverCommit Disk Groups Volumes Low Thresh Mid Thresh High Thresh Sec Fmt Health
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------
A **confidential info erased** 512 19.1TB 94.4GB 0B Enabled 1 1 50.00 % 75.00 % 97.75 % 512e Degraded

Reason
Action
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
The virtual pool space high threshold has been exceeded.
- Add a disk group, or remove data from the pool to reduce the space usage below the high threshold. Do not shut down or remove the controller modules until space usage is below the high threshold.

-----------------------------------------------------------------------------------------------------------------------------------------------------------------------
Success: Command completed successfully. (2023-10-25 15:06:33)
# show cache-parameters
System Cache Parameters
-----------------------
Operation Mode: Active-Active ULP
PI-Format: Disabled
Cache Block Size: 512

Controller A Cache Parameters
-----------------------------
Write Back Status: Disabled
Cache Flush: Enabled

Controller B Cache Parameters
-----------------------------
Write Back Status: Enabled
Cache Flush: Enabled

Success: Command completed successfully. (2023-10-25 15:06:37)
#

[JonPaul · Accepted solution]

@gwijnants 
Is your Pool Overcommitted?
In the event that a Pool is overcommitted and the Pool High Threshold is exceeded the controller will go into WRITE-THROUGH mode to protect data in flight.  The high threshold is automatically set to 200GB or (400GB in IN210R004 firmware) below the pool capacity.
I can see from the below that the Pool Overcommit is enabled but only by adding up the volume capacity will you be able to determine if the Pool is overcommitted.
You can see some detail on this in the MSA 2060 Best Practices Guide:  https://www.hpe.com/psnow/doc/a00105260enw
Look for "Threshold"

[gwijnants]

Hi JonPaul,

Thank you for the solution! Indeed the pool was overcommitted. After adding capacity the status went back to Active.

Best Regards,

Guy

[Sunitha_Mod]

Hello @gwijnants,

That's awesome! 

We are extremely glad to know the problem has been resolved.