Read only SSD cache not filled after reboot

[captainfred]

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

[b0wi]

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.

[brantje]

But a reboot is a proper shutdown, so it makes no sense that the cache is cleared upon reboot.

 

 

Posted via MyXpenology

[captainfred]

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.