HP StorageWorks MSA2312fc HP StorageWorks 2312fc and 2324fc Modular Smart Arra - Page 35

LED Description 10 Cache Status 11 Host Activity Definition Green - Cache is dirty (contains unwritten data) and operation is normal. The unwritten information can be log or debug data that remains in the cache, so a Green cache status LED does not, by itself, indicate that any user data is at risk or that any action is necessary. Off - In a working controller, cache is clean (contains no unwritten data). Blinking green - A CompactFlash flush or cache self-refresh is in progress. Indicates cache activity. (See also If the controller has failed or does not start, is the Cache Status LED on/blinking?) If the LED is blinking evenly, a cache flush is in progress. When a controller module loses power and write cache is dirty (contains data that has not been written to disk), the super-capacitor pack provides backup power to flush (copy) data from write cache to Compact Flash memory. When cache flush is complete, the cache transitions into self-refresh mode. If the LED is blinking momentarily slowly, the cache is in a self-refresh mode. In self-refresh mode, if primary power is restored before the backup power is depleted (3-30 minutes, depending on various factors), the system boots, finds data preserved in cache, and writes it to disk. This means the system can be operational within 30 seconds, and before the typical host I/O timeout of 60 seconds at which point system failure would cause host-application failure. If primary power is restored after the backup power is depleted, the system boots and restores data to cache from Compact Flash, which can take about 90 seconds. The cache flush and self-refresh mechanism is an important data protection feature; essentially four copies of user data are preserved: one in each controller's cache and one in each controller's CompactFlash. Blinking green - At least one host port has I/O activity. Off - Host ports have no activity. HP 2312fc and 2324fc Modular Smart Array user guide 35