topic set the global wafl.optimize_write_once flag to off in Netapp V9.3 (C-Mode) in ONTAP Discussions

set the global wafl.optimize_write_once flag to off in Netapp V9.3 (C-Mode)

Jas — Wed, 04 Jun 2025 12:24:18 GMT

I would like to update or print the flags which were available earlier in ( diagnostic previlage).

In the new Version of Netapp (V9.3), how can i check or update the below flags;

1, wafl.optimize_write_once flag to off

2, Set wafl_max_write_alloc_blocks to 256 on the aggregates

I would also like to check the status of these flags before update.

Appreciate your help..!

Re: set the global wafl.optimize_write_once flag to off in Netapp V9.3 (C-Mode)

paul_stejskal — Wed, 10 Jul 2019 14:43:10 GMT

Why are you looking to set this? Was it due to a prior bug?

Please open a case because we need to review those settings and those are very specific. Modifying non-publically available values without knowledge of what they do from Support/Engineering will cause system problems or unexpected situations we cannot guarantee will be safe or well functioning.

Re: set the global wafl.optimize_write_once flag to off in Netapp V9.3 (C-Mode)

Jas — Thu, 11 Jul 2019 04:50:01 GMT

We are Implementing Exchange on our Storage, The best practices of Exchange based on the Netapp Document: TR-4221

I want to update the flags based on the above recommendations, let me know how can i proceed.

Re: set the global wafl.optimize_write_once flag to off in Netapp V9.3 (C-Mode)

paul_stejskal — Thu, 11 Jul 2019 14:25:15 GMT

Hmm, that seems odd. I think that's more a recommendation for FAS/spinning drives than AFF. Again, while this may seem like a simple request, I'd like to get a case opened so we can give it our best watchful eye. Since I don't see your system details I cannot provide guidance.

Thank you for following up.

Re: set the global wafl.optimize_write_once flag to off in Netapp V9.3 (C-Mode)

TMACMD — Tue, 16 Jul 2019 15:03:15 GMT

Open a Support Ticket Please!!!_____Open a Support Ticket Please!!!_____Open a Support Ticket Please!!!

It is a VERY GOOD idea to open a case with NetApp to track this change on your system.

Get the Current Status:

With that said, those options are set in two different locations. One is on the node (before creating the aggr) and the other is on the aggr (after setting the node option and creating the aggr)

To set the ndoe option wafl.optimize_write_once, you need to do that from the NODE SHELL.

Get the Current Status: system node run -node * options wafl.optimize_write_once

Set the option to off: system node run -node * options wafl.optimize_write_once off

***If you do not need it set on all nodes, then be sure to specify nodes instead of using "*"

To modify the Aggregate option, (first be sure the NODE option is set on all controllers that WILL contain the Exchange AGGRs), create the aggregate (GUI or CLI) and then modify it with the option change:

aggr modify -aggregate <EXCH_AGGR_01> -max-write-alloc-blocks 256

To set the option wafl.optimize_write_once, you need to do that from the NODE SHELL.

Get the Current Status: system node run -node * options wafl.optimize_write_once

Set the option to off: system node run -node * options wafl.optimize_write_once off

Re: set the global wafl.optimize_write_once flag to off in Netapp V9.3 (C-Mode)

Jas — Wed, 17 Jul 2019 05:56:34 GMT

Thank you all for your Guidance.

I will for sure open a case before updating the parameters.