SU537: [Impact: Medium] StorageGRID SG6000s may experience higher than normal read latency on flash read cache enabled volumes while running SANtricity OS 11.70.4 and 11.70.5 versions

Views:: 284

Last Updated:: 8/22/2023, 9:55:06 PM

免责声明：
联想凌拓科技有限公司（“Lenovo NetApp”）不对本页面中提供的任何信息或建议的准确性、可靠性或可维护性，或通过使用这些信息或遵守本文中提供的建议可能获得的任何结果，提供任何陈述或保证。本页面中的信息是按原样分发的，使用这些信息或实施本文中的任何建议或技术是客户的责任，取决于客户评估这些信息并将其整合到客户的运营环境中的能力。本页面及其包含的信息只能与本页面中讨论的 NetApp 产品结合使用。在任何情况下，Lenovo NetApp 均不承担因与使用或执行本页面上提供的信息有关的或导致的任何特殊的、间接的或随之而来的任何损失，或者因使用、数据或利润损失（无论是否在合同履行中）、疏忽或其它侵权行为导致的任何损失。

更多最新信息请参考 NetApp 官网支持公告

Summary

[Impact: Medium]

StorageGRID SG6000s may experience higher than normal read latency on flash read cache (FRC) enabled volumes while running SANtricity OS 11.70.4 and 11.70.5 versions.

Issue Description

In rare circumstances, StorageGRID SG6000 systems might experience higher than normal read latency on FRC enabled volumes while running SANtricity OS 11.70.4 and 11.70.5 versions. FRC is enabled and required for Cassandra volumes.

Symptom

StorageGRID appliances impacted by this may experience Cassandra read timeouts. This knowledge base article’s issue section outlines the commands that can be run on the controller shell to identify and quantify the latency.

How to Identify Exposure:

From https://aiq.netapp.com, go to the E-Series Daily_CSB AutoSupport.
Check the section CUMULATIVE-DRIVE-VOL-STATS.XML.
Search for UserLabel="StorageGRID-obj-00" to find the statistics for the volume with the Cassandra database.
Find the values for flashCacheReadHitBytes and readBytes.
Check the values in flashCacheReadHitBytes and readBytes for a percentage of 80% or more.
The calculation is (100*flashCacheReadHitBytes/readBytes).

Example:

<readBytes>957076294144</readBytes>
<flashCacheReadHitBytes>951014879744</flashCacheReadHitBytes>
100*951014879744/957076294144=99%

Workaround

Contact NetApp Support to determine if a downgrade of a SANtricity is necessary on StorageGRID appliances exhibiting higher than normal flash read cache latency.

Solution

Upgrade to StorageGRID Appliance 2023.08 or later.

NetApp provides no representations or warranties regarding the accuracy or reliability or serviceability of any information or recommendations provided in this publication or with respect to any results that may be obtained by the use of the information or observance of any recommendations provided herein. The information in this document is distributed AS IS and the use of this information or the implementation of any recommendations or techniques herein is a customer's responsibility and depends on the customer's ability to evaluate and integrate them into the customer's operational environment. This document and the information contained herein may be used solely in connection with the NetApp products discussed in this document.