23. Quick info on most Popular Transparent Huge Page Alerts on HANA DB ?

Most of the basis peoples would have experienced this alert on HANA Studio/Cockpit. As part of "HANA DB - Recommended OS settings", we would have definitely crossed this THP information.

Let's discuss this with two cases.

Case 1: If your OS is SUSE >=15 SP5 or RHEL >=9.2

There are three values which we can set -> madvise, always, never

Value should always be "madvise" - Not "Always" for our case 1.

The word "Active" in note 2031375 vers10 resolution statement denotes that it shouldn't be "never" (disabled). It's an generic word. We should not confuse take this active word as an "always" value (denote).

As mentioned in Note 3523701 - Transparent Huge Pages (THP) Alert vers 5, reason for these alert is that the underlying check is not aware of these new allowance/changes in recommendation for SUSE >= 15 SP5 or RHEL >= 9.2.

 
Hence, we can ignore these alert ids 116 for time being. We can also disable the alert by following Note 3523701.
 
Further, an update to the alert handling will be made available in a future HANA revisions. You can revisit SAP Note 3523701 in future for the same.

✨In simple words, Just set "madvise" and ignore alerts if generated for our case 1 OS.

Note 2131662 clearly states that we need to set "madvise" only.

I have even seen scenario which no alerts generated for RHEL 9.2, However, After OS upgrade to 9.4, it generated alerts id 116. These are due to the condition that checks were not aware w.r.t OS/HANA. 

Case 2: If your OS is SUSE < 15 SP5 or RHEL 9.2

✨Value should always be "never" since older OS not suitable/compatible to handle Transparent Huge Pages.

We can check any older OS recommendation notes such as 1824819. It will state the same.

😌, I have handled these kind of alerts and explained to multiple basis persons without knowing what is THP at first?

Let's other basis peoples should not do the same.

Here's the simplest explanation which I understood.

1) Data is stored in memory - In memory HANA Database concept

2) A Set/Block of memory is Pages 

3) These pages will be increased/decreased for the DB operations accordingly.

4) However, HANA can't handle this kind of operations and crashed when doing commit.

SAP did some advancements in Case 1 OS to have "madvise" and avoid crashes during commits.

However, In  Case 2 - older OS, we need to set "never" to avoid crashes.

Hope you like this tick😊

Thanks for visiting !!!