On Wed, Aug 21, 2019 at 3:35 PM Xinhuan Zheng <xzheng at christianbook.com> wrote: > Hello Everyone, > > We are using CentOS 5 system for certain application. Those are VM guests > running in VMware. There is datastore issue occasionally, causing all file > systems becoming read only file systems. > - Xinhuan Zheng > Orthogonal consideration: I don't know the version of vSphere you are using and if you are using or not VMware Tools inside your guests. But installing VMware tools in vSphere 4 or higher has the effect to change disk timeout for the guest to 180 seconds, from its default of 30 seconds (that I think is the same for RH EL/ CentOS 5,6,7) This may or may not help you in case of short time storage problems. Eg on a 6.5 infrastructure with an old legacy CentOS 5.9 VM I have VMware Tools: Running, version:8305 (Unsupported older version) and inside guest # service vmware-tools status vmtoolsd is running # # find /sys/class/scsi_generic/*/device/timeout -exec grep -H . '{}' \; /sys/class/scsi_generic/sg0/device/timeout:180 /sys/class/scsi_generic/sg1/device/timeout:180 # See also: this if you have access to Red Hat Customer Portal (disk scsi timeout and how to set it in RH EL 5): https://access.redhat.com/solutions/301963 Similar considerations for RH EL 6 and 7: https://access.redhat.com/solutions/2470541 This publicly accessible for RHEL 5 https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/5/html/Online_Storage_Reconfiguration_Guide/task_controlling-scsi-command-timer-onlining-devices.html this related to vSphere: https://kb.vmware.com/s/article/1009465 this for APD (All Paths Down) timeout that defaults to 140 seconds for block storage https://kb.vmware.com/s/article/2032934 HIH, Gianluca