captainfred Posted February 7, 2016 Share #1 Posted February 7, 2016 Hi, Is it normal for read only SSD cache to reset / go back to zero after a reboot? Seems to happen whatever version of XPEnoboot I use... DSM is 5.2 5592 Update 4. Hardware is HP MicroServer Gen8. Any fix for this? Thanks Link to comment Share on other sites More sharing options...
b0wi Posted February 8, 2016 Share #2 Posted February 8, 2016 Yes, see this movie for more information: SSD Cache tip #1, don't kill the power! I was doing some electrical work on the house and shut off the breaker for the circuit I was working on. I didn't know that same breaker also ran power to my office and that shut off the Synology disk station and SSD cache. The SSD memory is of course non-volatile, but the ~1GB of system RAM used to index into that cache is volatile. So upon powering back up, I found the SSD cache usage had reset back to 0%. The cache itself was still there and working, just that all the previously cached data had been lost. I didn't lose any data off the DiskStation, no errors reported aside from the notification of an improper shut down. If you do a proper shut down, the cache index data is saved to the hard drives and is restored upon powering back up. Time to start designing a backup power system for that NAS. Link to comment Share on other sites More sharing options...
brantje Posted February 8, 2016 Share #3 Posted February 8, 2016 But a reboot is a proper shutdown, so it makes no sense that the cache is cleared upon reboot. Posted via MyXpenology Link to comment Share on other sites More sharing options...
captainfred Posted February 10, 2016 Author Share #4 Posted February 10, 2016 Exactly. It didn't lose power at all. I just rebooted from within DSM. I also tested it (after building the cache a bit) with a proper shutdown and powered it back on and it still cleared it. I assume then this isn't supposed to happen? Tested it with XPEnoboot 5.2-5592.2 and 5.2-5644.4. Link to comment Share on other sites More sharing options...
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