We may also see VMkernel logs a lot of SCSI reservation conflicts error, If storage is slow or any other underlying issue with Storage.
This behavior was hugely experienced from Linux virtual machines but windows virtual machines will not go into read only mode.You may see filesystem retries (scsi bus resets) in windows event logs. If the failover occurs before the timeout, everything will continue as normal without any issue to virtual machines. If the SCSI timeout occurs before the storage becomes available to esx host, which might make the linux file system to read only.
As per Redhat article ,When a storage failure occurs at the VMware Hypervisor level, It may takes longer sometime than the actual SCSI timeout to expire. This issue is caused due to the temporary disconnection to storage disks. We need to reboot the server always to fix the issues. Redhat Linux virtual machine running in VMware platform continuously facing issue of file system becomes read only mode and avoids the write operations at file system level. Diff VCenter 5.5 appliance and vCenter on WIndows.