I am benchmarking with the YCSB tool doing 1k writes.
Below are my server specs
12 core hyperthreaded processor
From what we are seeing it looks like the kernel writing to the disk causes
Please let me know
From: Jeff Jirsa [mailto:jji...@gmail.com]
Sent: Friday, January 5, 2018 5:50 PM
Subject: Re: NVMe SSD benchmarking with Cassandra
Second the note about compression chunk size in particular.
On Jan 5, 2018, at 5:48 PM, Jon Haddad
Generally speaking, disable readahead. After that it's very likely the issue
isn’t in the settings you’re using the disk settings, but is actually in your
Cassandra config or the data model. How are you measuring things? Are you
saturating your disks? What resource is your bottleneck?
*Every* single time I’ve handled a question like this, without exception, it
ends up being a mix of incorrect compression settings (use 4K at most), some
crazy readahead setting like 1MB, and terrible JVM settings that are the bulk
of the problem.
Without knowing how you are testing things or *any* metrics whatsoever whether
it be C* or OS it’s going to be hard to help you out.
On Jan 5, 2018, at 5:41 PM, Justin Sanciangco
I am currently benchmarking NVMe SSDs with Cassandra and am getting very bad
performance when my workload exceeds the memory size. What mount settings for
NVMe should be used? Right now the SSD is formatted as XFS using noop
scheduler. Are there any additional mount options that should be used? Any
specific kernel parameters that should set in order to make best use of the
PCIe NVMe SSD? Your insight would be well appreciated.