While using other servers like iSCSI server deadlock can occur on the host system that try to run the iSCSI target in a guest virtual machine. There are many flaws that can come within an OS to response to the virtual machine's request. Some problems are caused by cache manager component that gives some delays in the response related to an error. Till the time the error is coming the guest gets blocked and unstability occurs in the virtual machine itself. To solve this problem environment variables can be set by setting the variable VBOX_DISABLE_HOST_DISK_CACHE to 1.