vSAN Performance issues with INTEL Optane Cache Drives
Article ID: 326779
Updated On:
Products
Issue/Introduction
Symptoms:
More IOPS and lower latency are expected utilizing Intel Optane NVMe based cache drives with vSAN.
This article is to inform of a setting change to increase performance with these drives if not running version 7.0U3c and later.
Environment
VMware vSAN 6.x
VMware vSAN 7.0.x
Cause
The latency caused by the log entry batch delay plus the actual time to write it to disk is shown in cache disk stats as WriteLE latency.
Every 1 second, the log flush timer is adjusted based on the number of writes that came into LSOM for this DG/cache during the prior second. With moderate IO this may result in some writes being delayed the entire default 1000us (1 ms).
Resolution
Upgrade vCenter and ESXi to 7.0U3c or higher.
If the upgrade is not possible and need to workaround, please contact Broadcom Support to investigate the issue.
Additional Information
Impact/Risks:
When utilizing non-Optane drives there may be negative performance impact for high I/O times and increased wear resulting in decreased life.
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