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VMware guest experiencing slow IO performance during fstrim

This document (000019768) is provided subject to the disclaimer at the end of this document.


SUSE Linux Enterprise Server 15 SP1
SUSE Linux Enterprise Server 12 SP5


During fstrim, a VMware guest is experiencing slow disk I/O performance and throwing the following errors:
EXT4-fs (dm-8): discard request in group:201 block:25351 count:8651 failed with -5
sd 9:0:0:0: timing out command, waited 180s
sd 9:0:0:0: [sdd] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_OK
sd 9:0:0:0: [sdd] tag#0 CDB: Unmap/Read sub-channel 38 00 00 00 00 00 00 00 14 00
print_req_error: I/O error, dev sdd, sector 852457322



This issue has been resolved on VMware vSphere 6.7 Patch ESXi670-202008001, as referenced on VMware KB#79277.



This is caused by a bug on ESXi 6.7 U2 or later, for more details please refer to WMware KB#79277 :
In ESXi 6.7 U2 or later Linux VMs fails unmap and windows VMs can hang or have slow IO performance (79277)


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  • Document ID:000019768
  • Creation Date: 30-Oct-2020
  • Modified Date:31-Oct-2020
    • SUSE Linux Enterprise Server
    • SUSE Linux Enterprise Server for SAP Applications

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