I recently rebooted my Unraid server because I noticed high RAM usage from the logs. After the reboot, I noticed many recent files were missing, including a vdisk of an Ubuntu server I just stood up a couple days ago. 
 

This has happened to me before as well after a reboot. Has this happened to anyone else or does anyone know why files might be missing after a reboot? The majority of it is there but I would say, maybe the last couple of weeks are missing. 

That would normally mean you have something writing to a location in RAM.   Quite why I have no idea.

 

You are likely to get better informed feedback if you post your system’s diagnostics zip file.

Thanks for the reply. I'm not sure why either. After the reboot, the server was running fine for a little bit then spiked again in RAM and has been running high for a few days straight. 128GB RAM and it's been showing 70% usage. I'm attaching the diagnostics zip file.

ajrfcounraid-diagnostics-20220522-0912.zip

your syslog is being spammed with messages of the form:

May 20 11:59:45 AJRFCOUNRAID emhttpd: *** bug: 5366 /mnt/user/appdata ssdcache
May 20 11:59:45 AJRFCOUNRAID emhttpd: *** bug: 5366 /mnt/user/virtualmachines ssdcache

According you diagnostics you have shares configured to use a pool called ‘ssdcache’, but this does pool not exist.   That in itself is not necessarily a problem as then Unraid would simply write to the array instead, but think you have something (probably a docker) configured to use /mnt/ssdcache so this location is getting created in RAM which starts getting used,  and then anything written to it will get lost on reboot.

 

The only SSD device I can see seems to be part of the array as disk5 which is not what you want as having the SSD as part of the array will significantly impact its performance due to the overheads of updating parity for all writes

Much appreciated. I did have an SSD cache previously but replaced it. I'll reconfigure the array with the cache again and see if that solves the issue. Thanks!