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Decide if we still need opensearch-madvise
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Description

In T264053, @EBernhardson created a small C program, elasticsearch-madvise to reduce kernel readahead settings, which greatly reduced I/O on our Elastic hosts. We're in the process of migrating to Opensearch, so we need to figure out whether we still need this optimization.

Creating this ticket to:

  • Figure out if the program is still needed (does the behavior still occur in Opensearch? Is there an easier way to do this with udev/sysctl or something?)
  • We still need it! Repackage for Opensearch! Happening in T387030

Event Timeline

bking renamed this task from Decide whether we need opensearch-madvise to Decide if we still need opensearch-madvise.Feb 12 2025, 10:39 PM
bking updated the task description. (Show Details)

Change #1119227 had a related patch set uploaded (by Bking; author: Bking):

[operations/puppet@production] cirrus: disable opensearch-madvise while we debate its future

https://gerrit.wikimedia.org/r/1119227

Change #1119227 merged by Bking:

[operations/puppet@production] cirrus: disable opensearch-madvise while we debate its future

https://gerrit.wikimedia.org/r/1119227

Gehel triaged this task as High priority.Feb 13 2025, 2:36 PM
Gehel moved this task from Incoming to Scratch on the Data-Platform-SRE board.
Gehel subscribed.

Moving to "Ops / SRE" column, this should be a purely SRE ticket, the Search Platform team should not need to be involved.

Based on this discussion, it seems like there are (or will be) better ways to approach this problem with Java and/or lucene properties. For the time being though, we will definitely need an opensearch-madvise. As such, we'll move forward with creating the opensearch-madvise package.

Looking back at T264053 , it appears that this repo is the source of the current Debian package. However, I'll wait for confirmation from my team before creating a new repo.

Per earlier IRC conversation, the latest elasticsearch-madvise repo is in Gerrit. I've imported it into a new repo hosted at Wikimedia's Gitlab .

Since we've decided to keep madvise, I'm closing out this ticket. Work on adapting and packaging opensearch-madvise continues in T387030

bking claimed this task.
bking updated the task description. (Show Details)

@Aklapper Thanks for pointing that out! It's something we should have on our radar, but until opensearch has completely replaced elasticsearch, I'd prefer to keep the gerrit repo open. Let me know if you prefer a different approach.