If your organization or customer is using a RamSan to store data on, you better check the firmware version of it. Some models, like the RamSan-620 running on an outdated firmware version will not have redundancy when one of the Flash chips fails. The RamSan should automatically failover to another Flash chip like in RAID1 but this will not happen. The result is that the LUN will not be available because the whole flash card will fail . Not nice when multiple virtual machines for instance are located on it.
RamSan has been sending out warnings and advisories to install the most recent firmware. Unfortunately there is no mentioning of this issue on the website of Texas Memory Systems!
Version 4.5.0 has the described issue which is fixed in version 4.5.4. Make sure you are running the latest firmware version. Contact RamSan support for instructions to download and install firmware.