Skip to main content
NetApp Knowledge Base

CONTAP-377578: SAS drive reporting not ready status may cause high client IO latency

  1. Last updated
    May 6, 2025
  2. Save as PDF
Views:
47
Visibility:
Public
Votes:
0
Category:
ontap-9
Specialty:
core
Last Updated:
5/6/2025, 2:22:14 PM

Issue

If a SAS drive returns an IO with not ready status then ONTAP keeps retrying the IO to wait for the drive to become ready. In some cases it may take the drive too long to become ready which can lead to long latencies for client IOs. This happens because ONTAP is not temporarily offlining the drive from the RAID group when this IO status happens.
EMS log:
[?]  Mon Oct 21 08:38:25 +0900 [node1: scsi_cmdblk_strthr_admin: scsi.cmd.notReadyCondition:notice]: Disk device 0d.16.1: Device returns not yet ready: CDB 0x28:628b3180:0008: Sense Data SCSI:not ready - Drive spinning up (0x2 - 0x4 0x1 0x0)(5970).
Note:2/4/1(0x2 - 0x4 0x1 0x0) is a standard SCSI check condition. It means LOGICAL UNIT IS IN PROCESS OF BECOMING READY.
This might also cause long CPs as observed in the EMS log:
Mon Oct 21 08:40:21 +0900 [node1: wafl_exempt07: wafl.cp.toolong:error]: Aggregate aggr1 experienced a long CP.

 

Sign in to view the entire content of this KB article.

New to NetApp?

Learn more about our award-winning Support

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.