Data Settings guidance for reader/writer threads change to 'disk i/o optimized' needs to be revised

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The guidance for choosing ‘Disk I/o optimized’ needs to be revised. Currently is says the following:

We want to be more nuanced about the guidance and not make a blanket suggestion to use this mode if using magma. Exact text/guidance TBD based on discussion with .

But in my opinion here are some scenarios for which we can recommended this setting ( please weigh in):

  • Durable write workloads where latency of such workloads is very important to the use case.

  • Very low residency ratio use cases with high speed NVMe disks and high write workloads?

  • What else?

cc

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Gary Gray
June 9, 2025 at 3:32 PM

The second part of this ticket is now part of a second PR, this one for the Magma the default storage engine. The perview of the changes are here: https://preview.docs-test.couchbase.com/docs-server-DOC-12489-magma_default_storage_engine/server/current/learn/buckets-memory-and-storage/storage-engines.html#storage-engine-magma

Basically, it just mentions you might want to use I/O optimized setting for Magma, and sends the user off to the already-edited page mentioned in my last comment. Note that the changes are in two different PRs, so the link on the preview page leads to the old content.

Gary Gray
May 29, 2025 at 2:06 PM

Note that this also needs to be cleaned up in the Magma section of the Storage Engines doc:

I’m tackling opart of this now because I am editing the section of the doc in question anyhow for an unrelated feature. I’ll need to do a follow-up PR to get the Magma section.

Sarath Lakshman
November 26, 2024 at 8:11 PM
(edited)

These are the scenarios to consider:

For Writes:

  1. If durable latency is more critical than write throughput, configure the writer threads to DiskOptimized.

  2. For write-intensive workloads, if you require increased throughput and the SSD is not saturated by the default settings, opt for DiskOptimized.

For Reads:

  • For low residency workloads, use DiskOptimized for better throughput and latency

  • This is particularly useful also for high-latency virtualized devices like EBS volumes on the Cloud. Higher I/O queue depth/concurrency is needed to saturate the disk IOPS/Bandwidth.

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Created November 26, 2024 at 7:37 PM
Updated June 9, 2025 at 3:32 PM
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